PROCEEDINGS OF THE XI INTERNATIONAL CONGRESS OF ARACHNOLOGY BRISBANE MEMOIRS OF THE VOLUME 33 11 NOVEMBER, 1993 QUEENSLAND MUSEUM PART 2 PREFACE The preparation for this International Congress was superbly managed by two Organising Committees. All members worked very hard and ] am very grateful for their cooperation. The Western Australian Museum was the centre of the Scientific and Publications Committee of Dr Mark S. Harvey, Dr Bill F, Humphreys, and Dr Barbara York Main. This group, lead by Mark Harvey, formed a fine team who very capably managed all scientific and publication matlers from manuscript submission to acceptance through the Congress program and photographic awards. The local Organising Committee included Dr Valerie Davies (Secretary), and Ms Tracey Churchill, Ms Jan Green, Ms Judy Grimshaw, Mr Phil Lawless and myself. That group managed diverse aspects of Congress organisation. Mr David Nebauer assisted committee members during the registration process. My preparation was initially assisted by Ms Julie Gallon. {n July 1991, Mr Philip Lawless took up the reins from Julie and proved to be a very dedicated and astute lieutenant, Emeritus Professor George Davies assisted the Secretary throughout the entire Congress period. Delegates from Russia, Kazakhstan, The People’s Republic of China, Madagascar, Mexico, Hungary, India, Belgium, North America, Germany, and Namibia were provided with varying degrees of sponsorship by the Queensland Museum Board of Trustees and sponsors. Their travel arrangements, often highly complex and problem-rich, were very capably managed by Ms Joanne Lavelle, then of State of Corporate Travel. Many a Congress delegate will no doubt fondly remember the Committee reception at the International airport. Several appreciated the kind hospitality of Mr Tony Luck, Microrim (Australia), of Camira, in an ‘Aussie barbeque’ before the Congress, Organisation of the Post-Congress tour to Cape Tribulation, was greatly facilitated by the much appreciated contributions of Ms Linda Stanley, Ms Esther Cullen, and Cliff and Gail Truelove. Editorial assistance was provided by Ms Gudrun Sarnes, Philip Lawless and Mr Neale Hall. The Congress organisers very gratefully acknowledge the financial donations of Australian Geographic Magazine, Wester Australian Museum, Amalgamated Pest Control, Australian Museum, Museum of Victoria, South Australian Museum, Commonwealth Bank, University of Queensland-Entomology & Zoology Departments, Griffith University—School of Australian Environmental Sciences, QANTAS Airlines, Australasian Arachnological Society, CSIRO, Division of Entomology, and the British Council. Financial support was also received from International Conference Support (loan) and the Australian Tourist Commission. The Queensland Museum Board of Trustees provided generous support for the Congress and the publication of these proceedings. Robert J. Raven Chairman, XIIth International Congress of Arachnology October 11, 1993 u F 5 y Ey A e tu Dr Joachim Adis Mg Rache) Allan Dt Andrew Austio Dr Léon Baer Mr Alberta Baran Dr Timothy Beaton Ms Emily Bolts Dr Allen Brady Ms Cathy Car De bames Carico Mr Refyn Cattey Ms Tracey Churchill Drjon Caddington Dr Valerie Davies Frof Genege Davies Dr Christa Deeleman Di Ene Duffey Mes Rita Doftey Dr William Ebeciarit Dr Janet Edmunds Prof Malcolm Edmunds Dy Mark Elgur Mr Theodore Evans Dr Peter Farweather Mr Richard Favtder Dr Martin Filmer Or Lyn Forster Dr Ray Forsiec Dr Rosemary Gillespie Mg Maureen Glover Dr Michael Gray. Ms Jao Green Ms Judy Grimshaw Or Charley Griswold Dr Crating Guerero-Treso Ms Grace Hall M3 Myriam Hoquin Or Mark Harvey Or johannes Hensohet Mr David Hirst a6 a7 110 99 33 11a 7 58 64 28 1d ey Dr Hubert Hofer Mr Chnis Holden Dr Peter Horak Dr Gustayo Hommiga Dr Peter Hudson Br Bill Humphreys Dr Gleny Hunt Ms Heli Hurme Dr Robert Jackson Dr Rudy Jacque Ms Sarth Kanko MrJoseph Koh Dr Akio Kondo De Peer Koomen Dr Seppo Kopunen Mk Salla Kuponen Prof. Ou Kraus Dy Margaret: Kraus 4 DreChnssan Keopf Mr Phibp Lawless Dr Pekka Lehriien Mr Peier Lanklater Dr Adan Locket Mr Man Longhatrom Mr Roger Lowe Or Volker Mahner| Prof, A,R.(Bert}Main Dr Barbara York Main Dr Patrick Maze Ms Sylyut Marc-Mallet Mr Roland Mckay Mr Grahant Milledge Dr Gary Miller Mrs Patneia Miller William Miller Dr Monika Miiller Me John Murphy Mts Frincea Murphy De Hitctsuge Ono Dr Visdimir Ovtsharenko Dr §, Pulanichamy Dr Ralph Platen Prof, Norman Plaimek Dr Gary Polis Dr Simon Palland Or Willian Preston Dr Robert Raven Dr George Roderick Dr Christine Rollard DrJéteme Rovner Mrz Phylhs Rovner Mp Ferenc Sumu Dr Petee Subwendingsr. Or Paul Selden Dr Givi Steswon Dr Keith Sondertand Mg Katherine Suter Mrs Valerie Suter Dr Rober Suter Dr Hirahurmi Suzuki 15 Dec lobo Talent 415 Dr Koichi Tanaka HTL Dr Chingys Tarahaey 66 40 Mr Phil Taylor Ms Margaret Tin 114 Drtohuo Trurusuyy a6 47 36 Dr Gabriele Uhr Dr Ignavio Vazquez Or Lenoy Vincent Mr Gor Vink Dr Fri Vofiath Ms Julianne Waldock Mr Doug Wallace DrFnedrich Wallenstein Dr Mary Whitehouse Mc Grahem Wishart Mrs Gwen Wishart 100 Dr Jorg Wunderlich 104 Dr Fredeno Ysnet CONTENTS PART 1 (Issued 30 June, 1993) Bruce, N.L. Two new gencra of marine isopod crustaceans (Cirolanidae) from Madang, Papua New Guinea ......, | CANNON, L.R.G, New temnocephalans (Platyhelminthes): ectosymbionts of freshwater crabs and shrimps ........... 17 CHIMONIDES, P.J. & Cook, P.L. Notes on Parmularia MacGillivray (Bryozoa: Cheilostomida) from Australia ......-..-.......600.- Al Cook, A.G. Two bivalves from the Middle Devonian Burdekin Formation, north Quecnsland ....:..:.- ttre eA? SHort, JW. Cherax cartalacoolah, a new species of freshwater crayfish (Decapoda: Parastacidae) fro northeast Australia ..........5.4.. Stee wer as Molde apo hp eS oe mobs wm Each let fates of 55 Hooper, J.N.A., KELLY-BorGES, M. & RIDDLE, M. Oceanapia sagitraria from the Gulf of Thailand ............ 0000.0 00c ccc eec epee cseaeesucvuess 61 RICHARDS, 8.J. & JOHNSTON, G.R. A new species of Nyctimystes from the Star Mountains, Papua New Guinea ................-. te ee to Van Dyck, S. The taxonomy and distribution of Petaurus gracilis (Marsupialia: Petauridac), with notes on its ecology and conservation status .6 0.0.0.0... cee cg stat bee etseceteaeucesvssuys ee 77 Dwyer, P.D. The production and disposal of pigs by Kubo people of Papua New Guinea ........... 000.000: +. 123 Davip, B. & Dace, L. TWO CAVES 22. ee ee eee ee eee ee, bie 9 he ote dey, Defect ate taglert ele telat VAM EL db elie alle o alte 143 Couper, P.J, A new species of Lygisaurus de Vis (Reptilia: Scincidae) from mideastern Queensland .,..,........ 163 Davirs, M., WATSON, G.F., MCDONALD, K.R., TRENERRY, M.P. & WERREN, G. A new species of Uperoleia (Anura: Leptodactylidae: Myobatrachinae) from northeastern Australia. ,167 DAVIES, V.T. HAND, S. First skull of a species of Hipposideros{Brachipposideros) (Microchiroptrea: Hipposideridae), from Australian Miocene sediments... 0.20.00. 020 ccc cece eee e ence peeyte be ep eeete:e 179 HAND, S., ARCHER, M., GODTHELP, H., Ricu, T.H. & PLEDGE, N.S. Nimbadon, a new genus and three new specics of Tertiary zygomaturines (Marsupialia: Diprotodontidac) from northern Australia, witha reassessment of Neohelos ..... 193 HEALY, J,M., LAMPRELL, K.L. & STANISIC, J. Description of a new species of Chama from the Gulf of Carpentaria with comments on Pseudochama Odhner (Mollusca: Bivalvia: Chamidac) ........0.5 0-05 ccc cece cece e. 211 Hunt, G.S. A new cayernicolous harvestman from lava tube caves in tropical Australia (Arachnida: Opiliones: Phalangodidac) ........, opt ah Et tape ta fale, i 2 217 INGRAM, G.J., NATTRASS, A.E.O. & CZECHURA, GV. Common names for Queensland frogs ...........4. aw alata! tpl iimotictllate oie slate ng oYeepe+$h} 221 JAMIESON, B.G.M. Spermatological evidence for the taxonomic status of Trapezia (Cmustacea: Brachyura: Heterotremata) . 2.0.0.0. ee cet bee eeeeees pr fet eee oh eee, cae eee JAMIESON, B.G.M. A taxonomic revision of the eastem Australian earthworm genus Perissogaster Fletcher (Megascolecidae: Oligochaeta) .................. bees ge lee ie srigurer hess KELLY, S.R.A. On the alleged occurrence of the Early Cretaceous ammonite Simbirskites in Queensland ......- -.--245 LAMBKIN, K.1. New information on the Australian small bittacids (Mecoplera) ..........-.....0-2-00-000 secu ee 253 Leacu, G.J, & Hines, H.B. Frequency of obseryation of bird species in sub-coastal farmland in southeast Queensland ........ -.259 Limpus, C.L., Couper, P.J. & Courer, K.L.D. Crab Island revisited; reassessment of the world’s largest Flatback Turile rookery after IWE]VE YCATS 6. ee ee cee te dence teen e ee tasers vbegeens note at os O39 (feo ale olf 277 PATERSON, R.A,, QUAYLE, C.J. & VAN Dyck, S.M. A Humpback Whale calf and two subadult Dense-beaked Whales recently stranded in southern Queensland ...........0. 00g acer eecece platelatecistt clas sie ealle belles sick fp Moline’ , 291 QuickKE, D.L.J. & INGRAM, S.N. Braconine wasps of Australia 2.2... 0.65505 cee ec cee eee eee e epee ceeegias sac Berls 12. 299 RICHARDS, S.J. & ALFORD, R.A. The tadpoles of two Queensland frogs (Anura: Hylidae, Myobatrachidae) ............005. the ttae dT INGRAM, G.J., COUPER, P.J. & DONNELLAN, S. A new two-toed skink from castern Australia ...........6.0.502.0.- NS FS CAS: tee ee a 34] WEBSTER, G.D. & JELL, P.A. Early Permian inadunate crinoids from Thailand ....... 0.00.00... cece cee eens niworts dae 349 WILLIAMS, S., PEARSON, R. & BURNETT, S, Survey of the vertebrate fauna of the Dotswood area, north Queensland ........-.,..5 he tot asa. 361 WILLIAMS, S., PEARSON, R. & BURNETT, S. Vertebrate fauna of three mountain tops in the Townsville region, north Queensland: Mount Cleveland, Mount Eljiot and Mount Halifax ...... 2.00.00. ccccuceseucueeeeeecetes ++. 379 NOTES ARNOLD, P. First record of ctenophore Coeloplana (Benthoplana) meteoris (Thiel, 1968) from Australia ...,.,,.. 16 CATTERALL, C.P. A record of the Common Planigale at Myora Springs: the first dasyurid from North Stradbroke Island .. 2... 2.0.0... 0.0 e cee eee ees faba os nde sundehectiolg teeta ctieta tity tebe tsle tet 54 Porter, R. & HUSBAND, G. A record of communal egg-laying in the skink Carlia tetradactyla ........0..0.0025, biereeeee eee 6D SHEA, G.M. New records of Lerista allanae (Squamata: Scincidae) ...... 0.2.0.0... 0c cece eevee ee eens -., +220 JeLL, P.A, & LAMBKIN, K.J. Middle Triassic orthopteroid (Titanoptera) insect from the Esk Formation at Lake Wivenhoe ..,,... 258 SIMPENDORFER, C.A. Pandarid copepods parasitic on sharks from north Queensland waters ....,....- asa Sst oss shige: 290 NaTIRASS, A.E.O. & INGRAM, G.J. New records of the rare Green-thighed Frog... ... 22.0... cece ee eee ev vey euceenees 348 JELL, P.A. + Late Triassic homopterous nymph from Dinmore, Ipswich Basin ............0000eecue uv aces +, 360 PART 2 (Issued 1] November, 1993) PROCEEDINGS OF THE XII INTERNATIONAL CONGRESS OF ARACHNOLOGY INVITED PAPERS SELDEN, P.A. Fossil arachnids-recent advances. and future prospects .............020. 0008 ote rewPose et 3he 389 Po.is, G,A, Scorpions as mode] vehicles to-advance theories of population and community ecology: the role of scorpions in desert communities ....,. 02.00.00. 00000 cece eee ce eee eens revees 401 ELGAR, M.A. Inter-specific associations involving spiders: kleptoparasitism, mimicry and mutualism ..:.,....... 41] CONTRIBUTED PAPERS Apts, J. & MAHNERT, V. Vertical distribution and abundance of pseudoscorpions (Arachnida) in the soil of two different neotropical primary forests during the dry and rainy seasons ...........,......... 431 AUSTIN, A.D. : Nest associates of Clubiona rabusta L. Koch (Arancae: Clubionidae) in Australia ............-.... 44] Bakr, L. AND JocQue, R. A tentative analysis of the spider fauna of some tropical oceanic islands. ........-.--.--. 00.005 . 447 BENTON, T.G. The reproductive ecology of Euscorpius flavicaudis in England ...- 16. essere cree eee ene e nee 455 CANARD, A. & STOCKMAN, R. Comparative postembryonic development of arachnids ..............0 6-200 0 eee eee 461 CaTLeY, K.M, Courtship, mating and post-oviposition behaviour of Hypochilus pococki Platnick (Araneae, Hypochilidae) ........ eeithe deuce be Lee Bae ode eo Be Lee ke Ate 469 CHURCHILL, T.B. Effects of sampling method on composition of a Tasmanian coastal heathland spider assemblage ..... 475 Davies, V. Topp. A new spider genus (Araneae: Amaurobioidca) from rainforests of Queensland, Australia .......-... 483 DEELEMAN-REINHOLD, C.L. An inventory of the spiders in two primary tropical forests in Sabah, North Bomeo........-.....-.- AQ] DuFrey, E. A review of factors influencing the distribution of spiders with special reference to Britain . oe. ADT EDMUNDS, J. The development of the asymmetrical web of Nephilengys cruentata (Fabricius) .... - .. Lopetapates 503 EpMmunps, M. Does mimicry of ants reduce predation by wasps on salticid spiders? ...........2..-2.. 20. .00000e 507 FAIRWEATHER, P.G. Abundance and structure of fossorial spider populations ... 2... 66 c ee ee ee eee ees $13 GILLESPIE, R.G. Biogeographic pattern-of phylogeny in a clade of endemic Hawaiian spiders (Araneae, Tetrapnathidae) .. 6.6.6... cece eee eee reeset eres atetheqreg tes reetts 519 GROMOV, A.Y. A new species of Karschiidae (Solifugae, Arachmda) from Kazakhstan . 2.00.2 ye rite cies ree 527 Hirst, D.B. A new species of Amaurobioides O.P,.-Cambridge (Anyphaenidae: Arancae) from South Australia... .529 Hormica, G, Implications of the phylogeny of Pimoidae for the systematics of linyphiid spiders (Araneae, Araneoidea, Linyphiidae) .... 6.62. ee ee ete ete eee 533 HUMPHREYS, W.F, Criteria for identifying thermal behaviour in spiders: a low technology approach ,..,....)-+,--)--, 343 Hunt, G.S. & MAuRY, E.A, Hypertrophy of male genitalia in South American and Australian Triaenonychidae (Arachnida: Opiliones: Laniatores) ©0002...) 26... c eee ee ete eee eben creer eer eeees 551 JACKSON, R.R. & WILCOX, R.S. Predator-prey co-evolution of Portia fimbriaia and Euryattus sp., jumping spiders from Queensland . . .557 JocquE, R. “We'll meet again”, an expression remarkably applicable to the historical biogeography of Australian Zodariidae (Araneac) .. 22. eee ee nee eet eer eee beep ees 61 Konbo, A., CHAKI, BE. & Fuxuba, M. Basic architecture of the ovary in the golden silk spider, Nephila clavata - 22.00.66... eee eee 565 Koomen, P. & PEETERS, T,M.J. New prey records for spider hunting wasps (Hymenoptera: Pompilidae) from The Netherlands ..,.... 571 KOPONEN, S. Ground-living spiders (Araneae) one ycar after fire in three subarctic forest types, Québec (Canada) . . 575 Kraus, O. & KRAUS, M. Divergent transformation of chelicerae and original arrangement of cyes in spiders (Arachnida, Araneae)... 1... ee tere er eet eas OiSn teste ee 7 579 LEHTINEN, P.T. ‘ Polynesian Thomisidac -a meeting of old and new world groups ....-. 65-6004. cee eee eee eee eens 585 Locket, N.A. Scorpion distribution in a dune and swale mallee environment ..........-..05 6-462 -s sees e eee 593 Main, B.Y. From flood avoidance to foraging: adaptive shifts in trapdoor spider behaviour 61... 66 cee eee eur es 599 MARC, P. Intraspecific predation in Clubiona corticalis (Araneae; Clubionidae) .., 0.00.) 065) eee see eee ees 607 MULLER, M.C. & WESTHEIDE, W. Comparative morphology of the sexually dimorphic orb-weaving spider Argiope bruennichi (Araneae: Ataneidae) . 02... eee cece pee etn e ea tbecvesuceuctnsvecs ts PLATEN, R. A method to develop an ‘indicator value’ system for spiders using Canonical Correspondence Analysis (COA), 3 stb bsnl nhs pa lay dewaabels tails be Boe ees cae ticle slates ROLLARD, C. The spiders of the high-altitude meadows of Mont Nimba (West Africa): a preliminary report , ROVNER, J.S. Visually mediated responses in the lycosid spider Rabidosa rabida: the roles of different pairs Of eyes .. 0... ek cee cece cece tee cneaeeutetbtenbeees SUNDERLAND, K.D. & Toppina, C.J, The spatial dynamics of linyphiid spiders in winter wheat ...............-.,. seihan genes SUZUKI, H. & Konbo, A. Morphology of the embryos at germ disk stage in Achaearanea japonica (Theridiidae) and Neoscona nautica (Araneida€) ... 2.2... 0.00 cee eect eeueeucesceceeces TARABAEY, C.K. An experiment on colonization of karakurt (Latrodectus tredecimguttatus, Black Widow spider) on island territories in Kazakhstan ..... 2.00... 000 cc eee uceeeusucetcutvauccsen TARABAEY, C.K., ZYUZIN, A.A. & FYODOROV, A.A. Distribution of Latrodectus (Theridiidae), Eresus and Siegodyphus (Eresidae) in Kazakhstan and Central Asia . 0... 0.0 cece cee eee cu ceca tapeencbetbiercsens TSURUSAKI, N. Geographic variation of the number of B-chromosomes in Metagagrella tenuipes (Opiliones, Phalangiidae, Gagrellinae) ©. ....... 00.0 ccc eee cece csvactecececuces URL, G. Mating behaviour and female sperm storage in Pholcus phalangioides (Fuesslin) (Araneae) .. .. , WISHART, G.F,C. The biology of spiders and phenology of wandering males in a forest remnant (Araneae: Mygalomorphae) . 2.0... 0... cece cece cece eee cc eve ccecetcencuees ‘ WUNDERLICH, J. The Macaronesian cave-dwelling spider fauna ........0..0.00 00.00 cc cece cecueueccecues YSNEL, F. Relationship between food intake and spider size in temperate zones: experimental model for an orb-weaving spider ................04. ts ce ee ee stre tT: dap bbptesy ZYUZIN, A.A. Studies on the wolf spiders (Araneae: Lycosidae). I. A new genus and new species from Kazakhstan, with comments on the Lycosinae .. 0.02.00... ccc cee ce sete cecvcuses + Mesos 615 SBD nti 639 rioby atts 687 FOSSIL ARACHNIDS-RECENT ADVANCES AND FUTURE PROSPECTS PAUL A. SELDEN Selden, P.A.1993 11 11: Fossil arachnids—recent advances and future prospects. Memoirs of the Queensland Museum 33(2): 389-400. Brisbane. ISSN 0079-8835. Until 5 years ago, the arachnid fossil record was Sparse. 1t was dominated by a comparative wealth of forms in Carboniferous Coal Measure sediments, and near-modern forms from Palaeogene Baltic amber, Both these relatively well-documented sources and the few reported finds elsewhere in the record suffered from erroneous interpretations. In recent years, few interpretations of existing fossils and a few spectacular new finds have filled in the gaps in the record and changed our knowledge and views of the course of arachnid evolution. Particular examples are: Devonian pseudoscorpions and spiders, bouk-lungs in Carboniferous scorpions, Triassic mygalomorph spiders, and Jurassic and Cretaceous araneomorph spiders. Phylogenetic systematic analyses of exiant arachnids have produced evolutionary scenarios which conflict with the observed fossil record in paris, The newly expanded knowledge of the fossil record allows better tests for the cladograms. Future work on reinterpretation of known Carboniferous and Palaeogene fossils, on rare Mesozoic arachnids, and on arachnids in the earliest known terrestrial ecosystems in the Silurian will add to our knowledge of the fossil record of the arachnids and further enhance testing of phylogenctic hypotheses, [Ag/aspidida, Arachnida, Chelicerata, palaeontalogy, phylogeny, Pycnegonida. Faul A. Selden, Department of Geology, University of Manchester, Manchester M13 9PL, United Kingdom; 10 November, 1992. For most of this century, one name dominated the literature on fossil arachnids, that of Alexander Petrunkevitch (1875-1964), Petrunkeviteh (1955; in Stgrmer, 1955) sum- marized the arachnid fossil record to mid-century (Fig. 1) in the ‘Treatise on Invertebrate palaeontology’ and although he published on amber spiders after 1955, the broad view of the fossil record of chelicerates remained little changed until about a decade ago. Few workers either published on fossil arachnids or disputed Petrunkevitch’s assignments during his lifetime. Only recently, during restucy of the fossils, have many errors and misinterpretations in his work come to light, In the fossil chelicerate record published 1n the ‘Treatise’ (Fig. 1), the Merostomata (essentially aquatic chelicerates) are sepatated from the Arachnida. Second, most of the arachnid side consists of dashed lines converging towards the base of the Cambrian, indicating lack of fossil record and uncertainty of affinities respectively, Third, apart from one dubious palpigrade and some scorpions, there are no other records of Mesozoic (Triassic-Cretaceous) arachnids. Fourth, there is a clear pattern in the temporal distribution of the fossils: a concentration of records in the Upper Carboniferous, and many inodem groups also occur in the Palaeogene (early Tertiary). The former records are from the Coal Measures of Europe and North America, for example: Mazon Creek, Ilinois: Coseley, England; and Nyrany, Czechoslovakia. The Palaeogene occurrences are mainly from Baltic amber. Although Trigonotarbida and a ques- tionable record of Araneae had been known from the Devonian Rhynie Chert of Scotland since Hirst (1923), they were omitted from the diagram. (In addition, Petrunkevitch knew of undescribed Lebanese amber opilionids and some Cretaceous spiders trom Manitoban amber). Petrunkeviich developed theories on the evolu- tion of arachnids, which resulted in his superor- dinal classifications of 1945 and 1949. He recognized a number of ‘evolutionary trends’, such as the movement of the mouth rearwards from the Xiphosura to the arachnids, and the teduction of the metasoma to a tail or pygidium. One of the most important characters used in his classifications 1s the width of the connection be- tween prosama and opisthosoma, i.e. reduction of the first abdominal somite to a pedicel Petrunkevitch (1945) divided the class Arachnida into two subelasses, Latigastra and Caulogastra, on the basis of a broad or a narrow prosoma-opis- thosoms connection respectively. Later, Petrunkevitch (1949) added the subclass Soluta to the scheme to include solely his new order Trigonolarbida which he considered exhibit beth wide and narrow junctions. Another subelass, the 390 Pseudoscorpionida Palpi gradida Schizomida Thelyphonida Ipugida Ricinuleida Xiphosurida Qranelda Jurassic || tine {|_| | FIG, 1. Stratigraphic ranges of Chelicerata and Aglaspidida and presumed phylogenetic relation- ships (from Stgrmer, 1955). Stethostomata, was created at this time to accom- modate the orders Anthracomartida and Hap- topoda which supposedly have a broad prosoma-opisthosoma junction and a unique coxosternal region. Petrunkevitch’s (1949) clas- sification scheme, used in the ‘Treatise’, has not stood the test of time. Weygoldt and Paulus (1979) noted its use in some textbooks but pointed out severe deficiencies in the scheme when other characters are taken into account. Petrunkevitch was a devout proponent of the idea of the ‘decoupling’ of macroevolution and microevolution. He envisaged major features (those which define higher taxa) originating by mutation or other accelerated evolution, whereas minor morphological differences (those which separate species, for example) could provide only long, slow evolution and rarely produced higher taxa (Petrunkevitch, 1952, 1953). Petrunkevitch (1955) envisaged extinction occurring when irre- MEMOIRS OF THE QUEENSLAND MUSEUM versible evolutionary trends took groups down blind alleys—useful trends which proved lethal when taken to extreme or when environmental conditions changed. Characters could therefore be described as ‘major’ or ‘minor’, depending on the taxonomic rank they diagnose. Provided the ‘rank’ of a character is not decided a priori, there is no problem; however, difficulties arise when character states do not clearly change at taxon boundaries. For example, in a diagnosis of the subclass Soluta Petrunkevitch, 1949 is: ‘ab- domen composed of 8 to 11 segments’ (Petrunkevitch, 1955, p. P107). Petrunkevitch described this variability as the character being in a ‘labile’ state. So, the subclass Soluta is diag- nosed on the labile condition of the abdominal segmentation, the presence of either a broad or a narrow junction between the opisthosoma and prosoma (see above), and the overall resemblance of the coxosternal region to that in spiders [my italics]. Petrunkevitch (1955) argued that solutes are not spiders because of the com- bination of characters in the group, and addition- ally they showed a single series of marginal plates on the opisthosoma. Obviously, such a group could also be considered a collection of quite different animals placed together through their shared possession of a spider-like coxosternal region. Restudy of fossil solutes reveals that the prob- lem lies mainly in Petrunkevitch’s inability to correctly interpret fossil material. The number of segments in the Soluta is invariably 11 (Shear et al., 1987) but the number Petrunkevitch inter- preted in each specimen differed according to its preservation. Thus, where a 2-segmented pygidium was preserved, then 2 additional seg- ments were counted over specimens which did not preserve this organ, and the short first ab- dominal segment is not always visible in fossils. Similarly, the interpretation of the prosoma-opis- thosoma junction depended on how closely these tagmata were conjoined in the fossil. Petrunkevitch described Trigonomartus pus- tulatus, and noted (1913, p. 104): ‘The cephalothorax being much harder, kept more or less its shape, and what appears on it as a median crest was in reality a median groove. The ir- regular, polygonal depressions were evidently thickened areas of the chitin and formed in life low elevations.’ But, two pages before he had diagnosed the new genus thus: ‘Carapace trian- gular with a median crest in the posterior half, covered with irregular polygonal depressions.’ Thus he had recognized that the fossils were FOSSIL ARACHNIDS external moulds but diagnosed the genus as if they were casts, The error perpetuated until 1955 When, in the ‘Treatise’ (p. P112), the diagnosis became ‘Carapace triangular, high, with median crest and a pustulose surface, without eyes. Ab- domen with pustulose surface’ Thus, pustules were recognized but the median crest remained, without explanation for the emendation. Further- more, eyes exist in Trigonomartus (Petrunk- evitch, 1913, pl. 9, fig. 49, in the same place as in Aphantomartus (Pocock 1911, PL. Hl. fig. 6). These two genera were synonymized by Selden and Romano (1983), As well as misinterpreting fossils, Petrunkevitch produced some illogical taxonomic arguments. In 1945, he erected the Aphantomartidae for eophrynids with 7 ab- dominal] tergites (ie. Aphantomartus areolatus Pocock. 1911). In 1949, he crected the Trigonomartidae, and, recognizing that Aphan- tomartus had & abdominal tergites, not 7, he stated (p. 256): “This means that the Family Aphantomartidae becomes a synonym of Trigonomartidae, the number of abdominal seg- ments having served as the only character of distinction.” Why not place the contents of the new ‘Trigonomartidae’ in the existing Aphan- lomartidae? Aphantomartidae has priority and was redefined by Selden and Romano (1983). Furthermore, illustrations purporting to differen- liate Aphantomartus and Trigonomartus ({Petrunkevitch 1955, figs 80, | and 3) are un- Tepresentative and merely emphasise different characters of the same genus. Fig. 80, 3 is not Aphantomartus areolatus, as stated in the text, but a copy from Pruvost (1919, fig. 42) of A. pococki, with eyes drawn on incorrectly! Consideralso the Phalangiotarbida, Kjellesvig- Waering redescnibed this proup just before his death in 1979, and the MS was being prepared for posthumous publication (see Kjellesvig-Waer- ing, 1978). In the MS, Kjellesvig-Waering, a renowned taxonomic ‘splitter’, reduced Petrunkevitch’s 10 genera and 13 species to four genera and five species. He stated in the introduc- tion to his MS: ‘Seldom, ifever, has a fossil group with such uncomplicated, mostly easily deter- minable morphological characters, been sub- jected to such misunderstanding and careless and erroneous work as has the order Phalangiotarbida Haase, 1890. The main reason for this state has been the complete failure of some of the workers in this group to understand fundamental paleon- tological principles of preservation, for example, molds and casts, external and internal, along with results of compaction and consequent reflection Of impression of ventral into dorsal surfaces and vice versa,’ Kjellesvig-Waering’s conclusions on functional morphology and phylogeny. both in this MS and his other work, are not without dispute, but his long experience with the taxonomy of fossil chelicerates was generally reliable. Kjellesvig-Waering wrote in his MS: ‘The question of whether Phalangiotarbida Haase, 1890, or Architarbida Petrunkevitch, 1945 is the proper name for this order of arach- nids has not been settled, although it is difficult to understand why any question should have arisen in the first place.” What Petrunkevitch did was to substitute an existing name with one based on better preserved specimens of the order: ‘What is more reasonable than to regard the Family Architarbidae as the most characteristic one of the Order and to emphasize this fact by using a proper derivative of the generic name for the Order?’ (Petrunkevitch, 1945, p. 11). The above examples show that much work is needed on fossil arachnids already in collections, in addition to siudy of the many new fossils wwailing description, THE FOSSIL RECORD (Fig. 2) ARACHNID RELATIVES The extinct aglaspidids are probably not chelicerates since they bear neither chelicerae nor other features which would ally them with the Chelicerata over any other arthropod group (Briggs et al., 1979), The fossil record does not help to determine the systematic position of the enigmatic pycnogonids. Chelicerae are not a pre- requisite for achelicerate. Sanctacaris Briggs and Collins, 1988 from the Middle Cambrian Burgess Shale of British Columbia lacks chelicerac. but was included in the phylum because of a com- bination of characters unique to Chelicerata: six pairs of prosomal appendages, cardiac lobe, prosoma and opisthosoma, and anus at rear of last trunk segment, Sancfacaris was described as sister to all other chelicerales, but may not be the oldest chelicerate because a dubious xiphesuran carapace of Lower Cambrian age, Eolimulus alavas (Moberg, 1892) was recorded from Oland, Sweden. Xiphosura are the most primitive chelicerales in existence and, though previously allied with the Eurypterida in the Merostomata_ most authors place Xiphosura with either the Scorpionida (Bergstrom, 1979, 1981; Bergstriim etcl,, 198(, van der Hammen, 1985, 1986) or as sister t all other chelicerates (except 392 Sanctacaris) (Grasshoff, 1978; Boudreaux, 1979; Paulus, 1979; Weygoldt and Paulus, 1979; Weygoldt, 1980), thereby rendering Meros- tomata an unnatural group. SCORPIONS Scorpions are the arachnid group with the ear- liest known ancestors; the most ancient known scorpion is Dolichophonus loudonensis (Laurie, 1889) from the Llandovery of the Pentland Hills, near Edinburgh, Scotland. Kjellesvig-Waering (1986) proposed a controversial classification scheme. Stockwell (1989) produced a more ac- ceptable classification scheme of Scorpionida which included fossils, but it has yet to be pub- lished formally. A linchpin of Kjellesvig- Waering’s classification was the supposed Devonian gilled scorpion described as Tiphos- corpio hueberi. Restudy of this material (Selden and Shear, 1992) revealed that it is not a scorpion but an arthropleurid myriapod! The early Silurian record of scorpions could be interpreted as representing the earliest terrestrial animals since all modern scorpions are terrestrial. However, all Silurian fossil scorpions occur in marine or marginal marine sediments, and mor- phological features suggest an aquatic mode of life. Petrunkevitch (e.g. 1953) considered all fos- sil scorpions were terrestrial, but other workers (e.g. Wills, 1947; Stormer, 1970; Rolfe and Be- ckett, 1984; Kjellesvig-Waering, 1986) argued for an aquatic habitat for Silunan scorpions at least. Evidence for aquatism among fossil scor- pions are: gills and digitigrade tarsi, as well as the absence of terrestrial modifications such as coxal apophyses, stigmata, book lungs, trichobothria, highly developed pectines and plantigrade tarsi. There is overlap in the ranges of aquatic and terrestrial scorpions but the first terrestrial forms probably appeared the Devonian (Selden and Jeram, 1989). It is not easy to decide whether a given fossil had an aquatic or terrestrial mode of life; the original environment of the enclosing sediment is commonly the best clue, but a recent find is worthy of especial note: well preserved book lungs in a Carboniferous (Visean) scorpion from East Kirkton, near Edinburgh, Scotland (Jeram, 1990). Few new records of fossil scor- pions have turned up in recent years although in MEMOIRS OF THE QUEENSLAND MUSEUM the otherwise sparsely recorded Mesozoic, scor- pions reported from the Triassic of France (Gall, 1971), and the Cretaceous of Brazil (Campos, 1986) are currently under study. PSEUDOSCORPIONIDA Many pseudoscorpions are known from the Tertiary (mainly in ambers, e.g. listed in Schawaller (1982, table 1), and some are known from Cretaceous ambers of Lebanon (Whalley, 1980) and Manitoba (Schawaller, 1991). How- ever, the most important fossil pseudoscorpions are well preserved specimens of Dracochela deprehendor (Shear et al., 1989; Schawaller et al., 1991), in the Upper Devonian mudstones of Gilboa, New York. Only protonymph and tritonymph are known which, though modern in many aspects, cannot be assigned with con- fidence to extant taxa because both diagnostic characters in the fossils and cladistic assessment of extant forms are lacking. SOLIFUGAE The Carboniferous solifuge, Protosolpuga car- bonaria Petrunkevitch, 1913, was described as being in a very poor state of preservation. It is impossible to judge the validity of the identifica- tion from the published photograph and drawing. The only reliable fossil solifuge is Happlodontus proterus Poinar and Santiago-Blay, 1989, from Oligocene Dominican amber. OPILIONES Until recently, Opiliones had a fairly typical arachnid fossil record, being known only from Upper Carboniferous strata and Tertiary ambers. In 1985 a specimen was discovered in Lower Carboniferous rocks of East Kirkton, near Edin- burgh, Scotland (Wood et al., 1985), and a year later, one was described from the Lower Cretaceous of Koonwarra, Victoria, Australia (Jell and Duncan, 1986). Both of these unnamed specimens are long-legged opilionids but no fur- ther identification is possible (pers. obs.). The order Kustarachnida Petrunkevitch, 1913 is included with the Opiliones, following Beall (1986). FIG. 2, Current knowledge of the fossil record of Aglaspidida, Pycnogonida and Chelicerata; data in Selden (1993). Solid lines denote actual occurrence in the stage(s) concerned; interrupted lines indicate presumed occurrence in intervening stages. ? denotes doubtful record. Note that taxon ranks are not equivalent; occurrences of important genera Sanctacaris (most plesiomorphic chelicerate) and Atfercopus (oldest and most plesiomor- phic spider) are shown separately. Stratigraphic resolution is to stage; abbreviations in second column refer to standard stage names (see e.g. endpapers of Briggs and Crowther, 1990). FOSSIL ARACHNIDS ue) im AXVLLY3L ' have secanvndbaveseh saved noni Loverofontyafivsvifiesvafescielateaf vee aa _ EpIUaziyos tf irr fe se vesvafennnn vsrsefessaufsany (BAdAIquiy \6Adoun, verre tana staafovesforsvaloonerfoonnetorevefoevenfoverefontesfunefyeved ovefeovestvonsafvonvaferrefonteaf ietvetoava Povsoftontefevenfoveiebeaisaf ieesfernnndreven aeydiowojeBAW aeyduoWionsiydr sovvaBovvsy onnonfonvea Bones Puno if yatet vate seater 1} ieee il epiquejousby | | epiysujoUnay ivan fovea fontsafiaieifeiecal (peubicjed epiya|si0unseuy ty en oe oy ot {i io savafessenfvorvaforone] veep eenof ere layNUoRy itd Bpiquejo|Buejeyg — it sate Jiervaferrsef rere love perene epjuoidossapnasy ane BErErPE ecezerstere 11 wna —_|Nvarrs] wwonoa [ono [ww ssssafoibof ietvafsAvnifvessfevsey osvendboave fades cdnafoson hover Bttefoviaa i) SNOwIS4INOBY WI PHALANGIOTARIIDA The situation of the phalangiotarbids has been described above. This group is only known from the Upper Carboniferous but fossils are widespread in European and North American coalfields. RiciNuLe! Ricinulei are known only from the Upper Car- boniferous of Europe and North America, and the New and Old World tropics at the present day (their range extends outside the tropics mainly by cavernicole species), A recent revision of the fossils (Selden, 1992) revealed a greater diversity in the Carboniferous than today, but based on an essentially similar body plan, It appears that the group has remained in warm, humid habitats (equatorial forest litter and caves) throughout its geological history. Mrres The oldest mites are Actinedida (Prostigmata) from the Lower Devonian Rhynie Chert of Scot- land (Hirst, 1923). Other Devonian Ac- tinotnchida are known from Gilboa, New York (Norton et al,, 1988, 1989: Kethley e¢ al, 1989), A few Jurassic and Cretaceous Actinotrichida are known (e.g. Bulanowa-Zakhavatkina, 1974; Krivolutsky and Ryabinin, 1976; Sivhed and Wallwork, 1978), but the majoncy of fossil mites are oribatids from Ballic amber (e.g. Koch and Berendt, 1854; Sellnick, 1918, 1931). Anac- tinotnchida are very poorly represented in the fossil record; there are no fossil Opilioacarida or Holothyrida and only a few, somewhat suspect, records of Ixodida (e.g. Scudder, 1890) and Gamasida (e.g. Hirschmann, 1971), Fossil mites are probably found routinely in palynological preparations but are unreported. With the growth of micropalaeontological techniques in the study of fossil arthropods it is likely that many more fossil mites will be identified, PALPIGRADI The preservation potential of palpigrades is even lower than thal of mites. Their small size, thin cuticles and interstitial habitats makes them difficult objects of study when Recent or fossil. Sternarthron zinteli Haase, 1890, from the Juras- sic lithographic limestone of Solnhofen, Ger- many, is doubtful; the only good fossil palpigrade is Palaeokoenenia mordax Rowland and Sissom, 1980, from the “Onyx Marble’ quarries (Pliocene) of Arizona. MEMOIRS OP THE QUEENSLAND MUSEUM Harroropa This monotypic order was established by Pocock (1911) on the basis of the subdivided tarsus of the first leg, Petrunkevitch (1949) cleaned and reexamined the specimens, and redefined the order based on 2 new interpretation of the abdominal segmentation. The group would repay restudy along with Anthracomartida and Trigonotarbida. ANTHRACOMARTIDA Together with Haptopoda, this order forms Petrunkevitch's 1949 subclass Stethostomata. In a discussion of the rationale for separating Stethostomata from Soluta (Shear and Selden, 1986: Shear et al., 1987), it was concluded that the only feature separating anthracomartids from trigonotarbids is two versus one rows of marginal tergal plates on the opisthosoma. Again. thiscom- mon Upper Carboniferous group needs careful restudy. TRIGONOTARBIDA Trigonotarbids are the best Known extinct arachnid group on account of their excelleni preservation in the Devonian Rhynie Chert of Scotland and Gilboa mudstones of New York and are among the first known land animals (Jeram ef al,, 1990). First described from Upper Car- boniferous rocks (Buckland, 1837; Fritsch, 1901; Pocock, 1902, 1903, 1911), Hirst (1923) described the first Devonian specimens (from Rhynic), and Stgrmer (1970) described forms from the Middle Devonian of Alken-an-der- Mosel, Germany. Trigonotarbida is one of the few arachnids groups found relatively frequently in Palaeozoic terrestnal rocks of from Argentina (Pinto and Hiinicken, 1980), Spain (Selden and Romano, 1983), Czechoslovakia (Oplusul, 1985), and Germany (Jux, 1982). The exquisite preservation of the Rhynie Chert meant that Hirst (1923) could describe minute details of the trigonotarbids from that deposit. Trigonotarbids from Gilboa (Shear et al., 1987) nat only confirmed Hirst’s observations but also uncovered further morphological features of these interesting animals, Later work has shown that some of the species described as trigonotar- bids in 1987 were really spiders or other pul- monate arachnids (Selden et al., 1991), but the systematic position of the Trigonotarbida, sister to all other pulmonates, was strengthened, A togonotarbid and centipedes, found together with early land plants in Silurian (basal Pridoli) sedi- ments at Ludford Lane, Ludlow, England (Jeram FOSSIL ARACHNIDS 39 et al., 1990), pushed back the earliest record of land animals by around 16 million years and indicated that tngonotarbids were among the ear- liest terrestrial animals. ARANEAR Great sindes have been made recently in spider systematics (Coddington and Levi, 1991) and concomitantly, new finds of fossil spiders have added to the geological record. The oldest spider is Affercopus fimbriunguis Shear, Selden and Rolfe, 1987, from Gilboa; supposed spiders from Rhynie (Hirst. 1923) and Alken-an-der-Mosel (Stormer, 1976) have been disproved (Selden et al., 1991). Attercopus ts sister to all other spiders; the patella-tibia joint is a rocking joint but in a more plestomorphic state than other spiders, lack- ing the “compression zone Y~ of Manton (1977). Autapomorphies of the Affercepus clade are: fimbriate paired claws. spinules on the palpal femur, and lack of trichobothna; the latter feature is puzzling. In spite of descriptions of Devonian and Car- honiferous araneomorph spiders (Archaeo- metidae Petrunkevitch, 1949; Pyritaraneidae Petrunkevitch, 1953), none of those seen by the author could be proved to be a spider at all. Petrunkevitch seemed to concur with Frisch (1904) and Pocock (1911) in their placement of fossils in the Araneomorphae without question, even if he disagreed with their detailed descrip- tions, All of these authors seemed to place fossils in Araneomorphae on the basis of their general resemblance to particular groups of araneomorph spiders rather than real characters. For example, Petrunkevitch (1953:107) defined Pyritaraneidac and redefined Arachaeometidae as araneomorph spiders with segmented opisthosomae, diffenng from each other by their latengrade and prograde legs respectively. Nowhere is the identification as arancomorphs guestioned. Eskov and Zonshtein (1990a) considered segmentation of the opis- thosoma in the Pyritaraneidae to be an artifact, but agreed that this family belongs in Araneomor- phae. Selden er al. (1991) studied Archaeometa nephilina Pocock, 1911 in the British Museum (Natural History) anda plaster cast of A. devenica Stormer, 1976 from the Senckenberg Museum, concluding that neither species was a spider and that A. devonica may not be an arachnid at ail. Carboniferous Arthrolycosidae Fritsch, 1904 and Arthromygalidae Petrunkeyitch, 1923 in the British Museum (Natural History) can be placed with the mesotheles because of the distinct ter- gites on their opisthosomae, Eskoy and Zonshtein W (1990b) argued fora new group of Carboniferous ‘Jabidognathous Jiphistiomorphs® on the evidence that the fossils lacked chelicerae yet any spider with orthognath chelicerae would have them preserved if the carapace and palps were. This argument presupposes that orthognath chelicerae are always porrect, which they may not be, To argue morphology from preservation (or lack of it!) is a dangerous practice. Until recently, no mygalomorph spider was known earlier than the Tertiary. Eskoy and Zonshtein (1990a) described some mygalomorphs from Siberia and Mongolia, plac- ing them in the modern Mecicobothriidae, Atypidae and Antrodiaetidae, They are excep- tionally well preserved, but poorly illustrated and described; in contrast, the line drawings are of high quality. In 1992, with the description of a Triassic mygalomorph, Rosamygale, our knowledge of the antiquity of mygalomorphs was more than doubled (Selden and Gall, 1992). This was placed in the extant family Hexathelidac, and suggests a widespread distribution of the family across Pangaea before nfling of the supercon- tinent. Hexathelids show many plesiomorphic characters among mygalomerphs but neverthe- less, mygalomorphs may yet be found in Palaeozoic rocks, Mesozoic spiders have only recently been dis- covered. The oldest fossil araneomorph is Juraraneus rasnitsyni Eskoy, 1984. placed in a new family, Juraraneidae. in the Aranevidea. Juraraneus, like the mygalomorphs described by Eskov and Zonshtein (1990). is well preserved but rather poorly documented for such an impor- tant Gnd, so itis difficult to be sure whether the placement is justified. Eskoy (1987) has also described Archaeidae from the Jurassic of Kazakhstan from where Filistatidae are currently being desenbed (Eskov, 1990). Recent finds of Cretaceous araneomorphs have emphasized the diversity of a spider fauna of modem aspect during this period, Unfortunately, some show little morphological detail (Jell and Duncan, 1986). but Selden (1990a) described specimens from the Lower Cretaceous of north- east Spain, beautifully preserved in lithographic limestone. The specimens included a deinopoid and a tetragnathid, so both cnbellate and ecribel- late orb-web weavers Were in existence at this time. In broad terms, by the Tertiary, the spider fauna was almost identical to that of today. and only 3 families are known to have become extinct since jhe Palaeogene (Eskov, 1990). 396 Uropyci Well preserved uropygids are found in Coal Measure rocks in Europe (e.g. Brauckmann and Koch, 1983) and North America, All are placed in the modern Thelyphonidae, SCHIZOMIDA Three species of schizomids are known from the Pliocene ‘Onyx Marble’ quarries of Arizona and one from the Oligocene of China (Lin et al., 1988). AMBLYPYGI Fossil amblypygi are known from the Coal Measures of Europe and North America and from Tertiary ambers (e.g. Schawaller, 1979). Amblypygi may be present in the Devonian of Gilboa;: a possible pedipalp tarsus was figured by Shear etal. (1984) and Ecchosis pulchribothrium Selden and Shear, 1991 may belong in this group (Selden et al., 1991). ARACHNID PHYLOGENY Selden (1990b) discussed three recent phylogenetic hypotheses with the evidence of the fossil record (Fig. 3). A cladogram which ac- curately reflects evolutionary events predicts that successive dichotomies should occur in ascend- ing chronological order, and a complete fossil record should show this. Weygoldt and Paulus’s (1979) analysis (Fig. 3c) predicts that palpigrades should occur in strata at least as old as Devonian because the more derived mites and pseudoscor- pions occur in beds of that age. In their scheme, Opiliones occupy a derived position. Van der Hammen (1989; fig. 3b) suggested that Opiliones should occur the Cambrian since they are tenta- tively shown as sister group to Xiphosura + Scor- piones. Shultz (1989, 1990; Fig. 3a) also placed Opiliones in a position which predicts their presence in Silurian times. Since scorpions were aquatic then, so would opilionids have been. None of the phylogenetic analyses (Fig. 3) in- corporated extinct groups, Whilst it is impossible to include ancestors in cladistic analyses, there is no reason why well known extinct groups should not be included, say at the Carboniferous level. Apart from the enigmatic palpigrades and the highly derived Schizomida, for which fossil evidence is lacking, all arachnid orders were in existence by that time. MEMOIRS OF THE QUEENSLAND MUSEUM Pseudascorparins / Palporadi Araneae Ainblypyat Urapyat % Sehigurtuda Opiliones Scorpones 4 SY * Solitugae Z sf c a Ka ya er / fr i ra wa < a Ves Shultz 1996 F i - a hey fi ms e 2 > = 3 2 = z 2 3 > = $ A a RF & ¢ - # 6 8 @ & @ z «O& c a & é < = =] < = Ss - r ~ f ys ‘ he vy Y ‘ \ _" yf a i ¥ vd ‘. Pa Pay SS \ a \ / ~. Z SN van der Hammen 1989 y Scorpions Vropyal Amblypyus Preudascarnianes / Xiphosura buryprerida Solltuqae Recirnuley nies Optliones Weygoldt ana Paulus 7979 FIG. 3. Cladograms of relationships among the arach- nid groups as viewed by a, Shultz (1990); b, van der Hammen (1989); andc, Weygoldt and Paulus (1979). Interrupted lines indicate uncertainty. FUTURE PROSPECTS Work in progress includes: palaeophysiology of early terrestrial chelicerates—aquatic and ter- restrial adaptations in eurypterids, scorpions, and other Siluro-Devonian arachnids; palaeobiology of the Trigonotarbida; and Cretaceous spiders from Canadian amber and the Santana Formation of Brazil. FOSSIL. ARACHNIDS Much of Petrinkevitch’s work needs revision. A new phalangiotarhid fauna has been collected in recent years from a coal mine tip in Somerset, England (Beall, 1991). Carboniferous Anthracomartida and Haptopoda need to be res- tudied. particularly in relation to the now ex- tremely well known and possibly related trigonotarbids, The identity of described Amblypygi is in little doubt, but modem descrip- tions would be helpful. In need of critical ex- amination are: the single fossil solifuge Protosolpuga from Mazon Creek, the supposed palpigrade Sternarthron from the Jurassic of Ger- many, and the amber spiders described by Petrunkevitch (e.g. 1942, 1950, 1958). The prob- lem with these spiders is that over the years some of the supposed ‘amber in collections has dis- coloured, which suggests 11 may not be truly Palaeogene but rather more recent copal or other TeSiNs, Successful palaeoarachnology requires knowledge of both Recent arachnids and under- standing of styles of fossil preservation. Much previous work suffered from erroneous inter- pretations of one sort or another. Goals for future work are: to understand the origin of the present- day diversity of arachnids and the relationships among the various groups, and the reconstruction of ancient terrestrial ecosystems. LITERATURE CITED BEALL, B.S. L986. Reinterpretation of the Kustarach- toda. (Abstract). American Arachnology 34: 4, 1991. 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A terrestrial fauna from the Scottish Lower Carboniferous, Nature 314: 355-356. SCORPIONS AS MODEL VEHICLES TO ADVANCE THEORIES OF POPULATION AND COMMUNITY ECOLOGY: THE ROLE OF SCORPIONS IN DESERT COMMUNITIES GARY A. POLIS Polis, G.A. 1993 1111: Scorpions as model vehicles to advance theories of population and community ecology: the role of scorpions in desert communities. Memoirs af the Queensland Museum 33(2): 401-410, Brisbane. ISSN 0079-8835, The diversity (5-16 species) and abundance (0.2-1.0 individuals/m*) of scorpions suggest that they may be quile ecologically important in desert communities. Ecological importance is considered in lerms of population energetics (the quantity of cnergy and mass flowing through populations) and of regulation of community structure and dynamics (influence on the distribution and abundance of other species). The energetic analysis provided three conclusions: 1) Scorpions monopolise a relatively large share of animal biomass, particularly relative to vertebrates and other arthropods, 2) This relative success is due to a suite of autecological traits (very low metabolism and very bigh assimilation efficiency leading to low energy requirements; and great tolerances fo water stress, heat and starvation) thatallows scorpions to prosper under the unpredictable and low food avgilability conditions that characterise deserts, 3) However, these traits lessen their impact on energetics, prey and competitors. Thus the importance of scorpions relative to homeothermic vertebrates is Jess than an analysis of density and biomass suggest because scorpions require and process prey in quantities relatively low to their biomass. Nevertheless, as a group, scorpions are probably important conduits of energy flow in deserts. Research on the interactions among scorpions and between scorpions and spiders strongly Suggests that scorpions can play key roles in the structure and dynamics of their communities. Studies in the deserts of California, Baja Califomia and Namibia show that intraguild predation by scorpions is a major force determining the (temporal and spatial) distribution, abundance and age structure of populations of thei competilors/prey.[Araneue, Scor- pionida, age structure, distribution, intraguild predation, population and community ecal- ogy. Gary A. Polis, Department of Biology, Vanderbilt University, Nashville, Tennessee 37235, U.S.A.; 26 October, 1992. Ecology is a rapidly developing area with a great deal of internal argument and disagreement. As in other fields, theory has advanced far more rapidly than empirical work. Consequently, much theory is controversial and in need of empirical evaluation, Scorpions possess a number of char- acteristics that make them Ideal models to test and advance ecological theory. Thus, it is relatively easy to collect rapidly great amounts of data and to manipulate experimentally individuals and en- tire populations. Research on scorpions has con- tributed to many areas of population, behavioral and community ecology: e.g., the evolution of life history theory (Polis and Farley, 1980), the evolu- tion and ecology of age-structured populations (Polis, 1984a, 1988; McCormick and Polis, 1986a), the dynamics of cannibalism (Polis, 1980a, 1981, 1984b), the dynamics of intraguild predation (Polis and McCormick, 1986b, 1987, Polis er al., 1989), the evolution and ecology of foraging strategies (Polis, 1980b; Bradley, 1988), patterns and processes in biogeography (Due and Polis, 1986) and the patterns and processes affect- ing community and food web structure (Bradley, 1983; Polis, 1991). In this paper | evaluate the ‘ecological importance’ of scorpions. Throughout, I indicate how research on scorpions has advanced our general understanding of ecology, Although scorpions occur in almost all non-boreal habitats. I focus on desert scorpions because much evidence suggests that they may be particularly important components of arid ecosystems and are a relatively ‘successful’ group. They are diverse. some taxa are extraordinarily abundant, and, as a group, they form a large proportion of the biomass of all desert arthropods and easily ex- ceed the biomass of all desert vertebrates. Their success arises partially because they exhibit several physiological and ecological traits that pre-adapt them to the Jow and unpredictable food levels of deserts. ‘Ecological importance’ can be expressed in terms of either energetics and nutrient cycling 402 {the quantity of matter and energy flowing through a population or functional group) or regulation of community structure and dynamics (the impact on diversity, distribution and abun- dance of other populations). ENERGETICS AND NUTRIENT CYCLING The importance of desert scorpions on energy and nutrient cycling is a function of the quantity of prey biomass captured. The amount of cap- tured biomass is a function of the density, popula- tion biomass, metabolism and efficiency of energy transfer. ] now present a very rough ap- proximation of the relalive importance of scor- pions to the flow of energy and nutrients in desert ecosystems. To approach this question, data were compiled from the literature reporting the diver- sity, density and biomass of various groups of desen taxa (see Polis, 1990, 1991b; Polis and Yamashita, 1991 for additional details). These data are not without bias and other problems. For example, studies are nal usually conducted in areas where the focal taxon is absent or care; nor are rare species studied as often as common ones. Consequently, the statistics presented here over- estimate density and biomass and should be taken as a first approximation of actual parameters. However, the data are instnictive and suggest that scorpions could be a major link in the flow of energy through desert communities. [Group [Density (nosh) | Diversity (na. species) [nm _| 14 | is [ose ‘(ares ina | Lizards 36.8243 tae | Insects _|35.t00%54.600 __|[s9zz796_ 10 | ‘Termites _[9,025.000+2,793,000 [91215 | Mammals 28.5421.3 eee te 241.810+ 336.850 sake 7_| [Millipedes [11502214 f2aeor | Spiders [32208800 |sdae267 | | ee TABLE 1. Estimated average density and diversity of Major taxa of desert macrofauna reported from the literature, Diversity 1s the mean number of species per taxon from local sites in different deserts. Density statistics were standardized to 4 per hectare basis, Means are reported with their standard deviations; n = sample size. Note that these statistics should be viewed as very rough approximations rather than absolute values, Note that data on ants were insuffi- cient to include here (see Polis and Yamashita, 1991 for further details). MEMOIRS OF THE QUEENSLAND MUSEUM How do desert scorpions measure against other groups of consumers for these parameters? First, scorpions are relatively speciose in deserts. On the average, 7.1 species co-occur in desert throughout the world (range: 2-16 sympatric species, typically, 5-9 species; Polis, 1990) (see Table 1 for comparison with other desert taxa). Furthermore, populations are often quite dense, averaging>3200 individuals/ha with several species maintaining populations 5000-10,000/ha (e.g., Shorthouse. 1971; Lamoral, 1978; Polis and Farley, 1980; Polis and McCormick, 19868; Bradley, 1986; Polis, 1990). On the average, scor- pions are reportedly more dense than all other macroscopic animal taxa in these deserts except ‘insects’, lermites, and isopods (ants are undoub- tedly also more dense) (Table 1). Since scorpions are among the Jargest of all terrestrial arthropods (adults of most desert species=0.5-10g; Polis and Farley, 1980), these high densities produce rather large estimates of standing biomass (= density of individual species x mass of indiyidual animal). Each species population of desert scorpion averaged 7.15 kg/ha. Only termites (and probably ants) support a greater population biomass per Prat ation per Biomass (kg/ha) | per taxon Allvenebrates || All arthropod [Atmacrofouna | ——idsse di TABLE 2. Estimated population biomass for various taxa taken from literature, Population biomass per Species is average wet weight of one species per hectare, This statistic was sometimes reported: how- ever, il was often calculated by multiplying the average mass of an individual times the density. Population biomass per taxa is calculated as the product of population biomass per species and average diversity of that taxon. Note that data on ants were insufficient to include. Additional information is reported in Polis and Yamashita (1991). n refers to the number of species in a particular taxon for which biomass data exist. Note that these statistics are only gross approximations of reality, SCORPIONS AS MODEL VEHICLES species or per taxon (from the ordinal level down) than scorpions (Table 2). When the biomass of all scorpions living sym- patrically in desert areas is calculated (= mass of individual species x average number of sympatric species), scorpions as a group exhibit a greater biomass (= 50.8kg/ha) than all other taxa except termites (=113.4Kg/ha) and the sum of all other insects (=521.2kg/ha; Table 2). Note also that the population biomass of scorpions is higher than any one group of vertebrates (e.g., mammals and lizards average 39.9 and 6.8Kg/ha) or all ver- tebrates combined (47.7kg/ha). Overall, scor- pions form 6.7% of the biomass of all macrofauna species combined, 7.1% of the biomass of all macroarthropods and 106% of the biomass of all vertebrates. Thus it would appear that they are important conduits for energy transfer in deserts. However, two characteristics lessen their importance. First, they exhibit the highest ecological (production) efficiencies (percent assimilated energy incor- porated into new biomass) of all taxa that live in the desert (Table 3). Second, they exhibit meta- bolisms that are extremely low relative to other poikilotherms and endotherms (Table 4). Al- though these features are powerful adaptations that allow efficient use of food and partially ex- plain the success of scorpions in deserts, they also function to decrease the amount of energy trans- Group P/A% Insectivorous mammals Small mammals ‘Other’ mammals ‘Homeotherms’ 3.1 Fish Social insects Terrestrial invertebrates* Solita Solita herbivorous insects detritivorous insects Solitary carnivorous insects Spiders Scorpions TABLE 3. Ecological (Production Efficiency) of various animal taxa. This efficiency is equal tothe proportion of assimilated energy that is incorporated into new biomass (=Production/Assimilation). Note that the highest efficiencies are found in carnivorous insects, spiders and scorpions. *Terrestrial inver- tebrates do not include insects or arachnids. (primari- ly from Humphreys, 1979; see Polis and Yamashita, 199] for further details). 403 ferred. Thus a gram of scorpion does not process as much food as a gram of arthropodivorous vertebrate. Overall then, desert scorpions are less important in energy and nutrient cycling than their diversity, abundance and biomass suggest. How much energy do desert scorpions process? We have two estimates. Polis (1988) calculated that average populations of Paruroctonus mesaensis used 9000 grams of prey/ha/year. The Australian Urodacus yaschenkoi requires 7900g/ha/year; this translates into 98,400 ants or 31,570 medium sized spiders eaten per hectare per year (Shorthouse, 1971; Marples and Shor- thouse, 1982). It is uncertain exactly how such figures for individual scorpions or for the sum of all sympatric species of scorpions compare to those for vertebrates. This is an interesting ques- tion to pursue. INFLUENCE ON COMMUNITY STRUCTURE AND DYNAMICS The second measure of ecological importance is to determine how a taxon influences the dynamics, distribution and abundance of other taxa. In theory, scorpions can influence desert communities in many ways: as predators affect- ing characteristics of their prey, as prey of other predators and as competitors of other arthropodivores. One of the basic questions in ecology is: ‘What factors determine the distribution and abundance of species?’ To approach this question, re- searchers often focus on groups of similar species that use similar resources; especially those resources the supply of which may be limiting and in demand (e.g., food). Such species groups Metabolic rate (ml/O2/gm/hr) Homeotherms (basal rates) rodents elephant Birds Poikilotherms (at 25°C) Insects Spiders 2.3-4,7 1.665 + 1.25 0.92 + 0.92 0.057 + 0.048 TABLE 4. Metabolic rates of various animal taxa. The data are taken from many sources. The sample size for insects is 82 species; for spiders, 8 species; and for scorpions, 7 species. (see Polis and Yamashita, 1991 for further details). 44 are called guilds (= a group of species that use resources in a Similar way and are thus potential competitors}. For example, guilds of desert granivores (birds, ants, rodents} all eat seeds, regardless of specific differences in resource ac- quisition. One approach to study guilds is to describe their pattems or structure. By guild structure, we mean the diversity and abundance of species members; spatial and temporal patterns and resource use (i.e., niche characteristics). However, such descriptive studies, although common, are not fully satisfying because they do not directly ad- dress the processes that prochice the observed patterns. An aultemative approach is to determine if guild members interact, and if so. can such interactions significantly shape guild stricture. There are several possible ways that guild members can interact. These range from cooperation and mutualism to competition and ever predatiors, Such predation among guild members is culled intraguild predation (Polis and McCormick, 1987; Polis ef al. 1989). Intmguild predation is an ubiquitous interaction among many as- semblages of potential competitor bul has received little formal attention from cither theorists or empiricists (Polis et al, 1989). One major theme of my research with scor- pions has been to analyze the characteristics and significance of intraguild predation. Many scor- pion prey items (other scorpions, spiders and solpugids) are also polential competitors with scorpions (Polis, 1990: Polis, 1991a. b: Polis and Yamashita, 1991)_1 present information on three systems; in each, scorpions frequently eal species in the same guild of arnhropodivorous predators and such intraguild predation significantly affects the distribution, abundance and population dynamics of these potential competitors. I used scorpions in these studies 4s models to delineate the charactenstics and dynamics of intraguild predation. These studies illustrate how scorpions have proved to be extraordinarily amendable for ecological research: large amounts of data can be collected, interactions (e.g., feedings) observed and quantified relatively easily, and individuals or Whole populations manipulated experimental- ly, For example, in the first study, field data were collected on 130,000 individuals, 2000 feedings and 6000 individual scorpions were manipulated in controlled field experiments. MEMOIRS GF THE QUEENSLAND MUSEUM INTERACTIONS AMONG SCORPIONS IN THE COACHELLA VALLEY Four species of desert scorpion co-occur in sandy habitats on the floor of the Coachella Val- ley (Riverside County, California). Three are in the family Vaejovidae (Paruroctonus mesaensts Stahnke, P. lutealus Gertsch and Vaejovis con- fusus Siahnke); ane (Hadrurus arizonetisis Ewing), the luridae (Polis and McCormick, 19869, 1987). Paruroctonus mesaensis form >95% of all individuals and occur at densities in the range of 0.2-0.5 individuals/ha; the other three species are relatively rare. Each species requires 2-5 years to mature and is composed of several distinctly sized year classes. Size changes Breatly, &.g., P, mesaensis increase 60-80 umes in weight from 0.03g (instar 2) to 2.0-2,5g (non- gravid adults). The year classes and species over- lap to various degrees in use of insect and arachnid prey; average overlap among all species is moderate to high (0.67 [prey size] and 0.43 [prey taxa]). Thus, the scorpions potentially com- pele for food. Extensive intraguild predation occurs among the four species; Table 5 presents a matrix of who eats Whom, Several factors characterize this in- traguild predation: 1) Each species was both an intraguild predator and prey. Such mutwal preda- tion occurs simply because the predator scorpion was always larger regardless of the species com- bination involved (n= 170 scorpion-scorpion predations). Thus scorpions of all species are vulnerable as they grow from small juveniles to full size adults and predatory reversals (mutual predations) are common, For example, young P. mesaensis scorpions are eaten by relatively larger adult P. lutealus and Vaejovis confusus; adult P. mesaensis prey on the (now) relatively smaller adults of these species, Thus age/size is a key PREY Hudtrurus 0.0 [Ptweotus foo [33.3 Jor 67 |467_| Pmesaenis fa sso [as | ta2_| vagjvie fon foo jaa [ao fizo | TABLE 5. Scorpion-scorpion predation in the Coachella Valley. The entries represent the percentof the diet that each species forms.as prey for each of the four scorpion species, The diagonal represents. in- Iraspecific predation (cannibalism) (from Polis & Mc- Cormick, 1987). H.ariz=Hadrurus arizonensis; Plat = Paruroctonus luteolus; P.mes= Paruroctonus mesaensis, V.con =Vaejovis confiisus. SCORPIONS AS MODEL VEHICLES determinate of intraguild predation: adults are the predators and immature individuals are the prey significantly more frequently than expected by chance. 2) The most common species (P_ mesaen- six) was the predator in 91% of all intraguild predations observed, Its average overlap in prey use (= 0.44) with other scorpion species was second highest. 3) Intraguild predation, atleastby P_mesaensis, ts significantly more frequent when prey availability was low: when <1% of the ulation was feeding, heterospecifics formed 35% ofall diet items, In contrast when the percent feeding was >S%, only 3.2% of all prey were other species of scorpion..4) Mortality caused by intraguild predation was generally an inverse function of the density of both P, luteolus and V. confusus, this resulted because much of the sur- face activity of these twospecies ocerred during (less productive) periods when /. mesaensis was absent from the surface. 5) Intraguild predation is Important in scorpion population dynamics. When analyzed as percent mortality of small species (here = total number of individuals eaten by P. mesaensis divided by the total number ever observed), intraguild predation by P. mesaensis killed 8% and 6% of all P. luteolus and V. can- Jusus ever observed, Cansuch high rates of montality cause the rarity of these species? It is only possible to approach this question using field experiments. Removal of >6000 P. mesaensis (=3.2Kg) from 300 (100m) quadrats over a 29 month period demonstrated that the rarity of these species is caused substan- ually by intraguild predation from P-_ mesaensis. 6) Both P. duteolus and V. confisus (but not H. arigonensis) increased significantly (600% and 135%) in removal as compared with 60 control quadrats. It was speculated that the rarity of the largest species (H. arizonensis) is a result of a bottleneck in adult recruitment; predation by P. mesaensis killed >10% of all newborn H. arizonensis observed during the study, 7) The age structure of these smaller species was significant- ly different in removal areas: first year juveniles were. 1.75 to 2.85 more abundant in removals versus controls. This suggest that the numerical response by the rarer species would be even more dramatic if this experiment continued beyond its 29 month period, Note that a plausible alternative hypothesis exists: removal of P. mresaensis relaxed exploitation competition and thus al- lowed the observed increases in density. A robust test failed to detect competition in this system {Polis and McCormick, 1986b, 1987). Thus, intraguild predation by P. mesaensis sig- 405 nificantly depressed the abundance of the rarer species. Does intraguild predation likewise affect their distribution? Since predation is apparently a key factor in the population dynamics of these species, natural selection is expected ta favor adaptations that reduce the probability that an individual will encounter its predator. Indeed prey oflen avoid places and tmes that their predators frequent or where the probability of predation is high (see Polis and McCormick, 1987). Typically, the large predatory entity (c.g., scorpion species and/or age class) occurs i productive periods und microhabitats whereus smaller entities coexist by spatial segregation in a heterogeneous habitat and by temporal dis- placement. The temporal and spatial distribution of smaller age classes and specics of Coachella Valley sceor- pions reflect avoidance (in ecological and/or evolutionary time) of larger age classes and species. The overall distribution of P. luteolus and V. confusus tend to place these species on the surface during Limes (in winter, late fall) and in places (off sand) characterized by relatively low surface populations of adult P. mesaensis. These umes and microhubitats support significantly less prey than those used by adult P. mesaensis; con- sequently P. mesaensix has a feeding rate (2.95%) siznificuntly greater than all other species com- bined (1.70%). Further, the minority of P- lureclus and V. confusus (hat forage when and where P. mesaerisis is active suffer a dispropor- lionately greater chance of being eaten by P- mesaensis, Intraspecific predation (cannibalism) has produced similar patterns of temporal dis- tribution, feeding and mortality patterns among age classes of P. mesaensis (Polis, 1980, 1984a), Thus, intraguild predation is an important fac- tor limiting the abundance and shaping the dis- tribution of these scorpiuns, Many other assemblages of desert scorpions exhibit pallerns ihat suggest that scorpion-scorpion predation 1s 4 major process shaping distribution and abun- dance (Polis and MecConnick, 1987; Polis, 1990, butsee Bradley, 1988). INTERACTIONS AMONG SCORPIONS, SPIDERS AND SOLPUGIDS IN THE COACHELLA VALLEY Scorpions also frequently eat competitors other than other scorpions. For example, the diet of the scorpion P, mesaensis consisted of 8% spiders and 14% solpugids (Polis and McCormick, 1986b). Does such intraguild predation sig- 406 nificantly affect the distribution and abundance of these unrelated taxa? Spiders responded in the above experimental removal of >6000 P. mesaensis by doubling in removal quadrats as compared to controls. Surprisingly, neither sol- pugids nor all insects combined increased sig- nificantly (all p>.05) in removal plots. These taxa did not increase either because individuals dis- persed from removal areas, because the increase of spiders and smaller scorpions compensated for the removal of P. mesaensis by eating surplus arthropods, or simply that scorpions exerted little impact on insect populations. The first explana- tion is likely true for widely foraging solpugids and is possible but unlikely for the more sessile insects. The second explanation is unlikely: the biomass increase of spiders and scorpions repre- sented <10% of the removed P. mesaensis biomass. The third explanation, difficult to ac- cept, is nonetheless a real possibility: P. mesaen- sis may take such a small proportion of all insects that its removal does not affect insect density. INTERACTIONS BETWEEN SCORPIONS AND SPIDERS IN THE NAMIB DESERT Predation by scorpions on spiders also appears to be a key determinant of spider densities in the Namib Desert (Polis and Seely, unpublished re- search, 1988, 1989). Both the scorpion Uroplec- tes otjimbinguensis (Karsch) (Buthidae) and the spider Gandanimeno echinatus (Purcell) (Eresidae) live under loose bark on larger Acacia trees and are the major arboreal predators of insects on such trees. Populations of G. echinatus are severely reduced when they co-occur locally on Acacia erioloba trees with the scorpion U. otjimbinguensis. This system is a model example how predator-prey interactions are complicated greatly by patterns of local distribution. Not all suitable patches (Acacia trees) contain the full array of local species capable of existing within the patch. Trees grow along the banks of dry rivers (e.g., the Kuiseb) and become less dense and more sporadic with increasing distance from the river bed. The local abundance of scorpions and spiders on each tree is a function of differen- tial dispersal, extinction and a predator-prey relationship with U. otjimbinguensis scorpions eating G. echinatus spiders, Although both species are found on river trees, U. otjimbinguen- sis is, with no exceptions, the numerically dominant species (10-50 scorpions/trees) and G. echinatus is relatively uncommon (5-20/tree). MEMOIRS OF THE QUEENSLAND MUSEUM This occurs because scorpions are effective predators on these spiders. However, this outcome is more variable on isolated trees further from the river and along smaller washes entering the river. On some trees close to the river, the abundance of scorpions and spiders is similar to that found in the river. How- ever, some trees have no scorpions and great numbers of spiders (50-400/tree); some trees have neither scorpions nor spiders; and some, no scorpions and few (<20) spiders. Overall, trees without scorpions support significantly more spiders (112.3+60.6, n = 21) than trees with scorpions (24.5+14.3, n =20) (p <0.001; only experimental trees scored). This variation in abundance and these distributions exist because neither U. otjimbinguensis nor G. echinatus dis- perse far from the river, yet spiders disperse fur- ther than scorpions. Dense spider populations occur only in more isolated trees where scorpions are absent. In trees quite distant from the river, neither species occur. Does intraguild predation by U. otjimbinguen- sis scorpions on G. echinatus spiders produce such patterns of distribution and abundance? Ad- ditions of Uroplectes over a one year period to scorpion-free trees (n = 11) highly significantly (p <.001) reduced G. echinatus populations to 42% of that on control trees (n = 12). Removal of scorpions from trees (n= 8) also produced a high- ly significant, 2.9 times increase in G. echinatus as compared to control trees (n= 12) with their full complement of scorpions, These experiments showed that intraguild predation was concentrated on young spiders and could significantly alter age distributions (p <.001 for each of the following comparisons): The smallest size class of spiders on experimental trees represented 49% of the population (n = 728 spiders) one year after scorpions were removed compared to only 31% (n = 221) on control trees where scorpions remained; similarly, the smallest size class formed 48% of all spiders (n = 903) on trees where scorpions were not present compared to 34% (n = 820) on those trees to which scor- pions were added. Thus differential dispersal and semi-deter- ministic biotic interactions combined with differ- ing isolation of patches are major determinants of the distribution, abundance and age structure of these species. In general, historical and stochastic dispersal events in patchy environments are a paramount factor explaining the distribution and abundance of predators and their prey and species of competitors (Polis, 1991b; Polis and SCORPIONS AS MODEL VEHICLES Yamashita, 1991). Such conditions can produce local extinclions or great variance in abundances via deterministic biotic interactions, but promote global coexistence. [ suspect that such situations are normal among many species living in the notoriously heterogeneous desert. Many such as- semblages occur in patches; differential disper- sal, local extinctions and ‘hide-and-seek’ dynamics are undoubtedly extremely important in determining the exact structure of local as- semblages. Unfortunately, little research has focused on these provesses. The system with scorpions and spiders on Acacia trees is ideally suited to analyze such processes and represent another example of the use of scorpions to ad- vance our comprehension of ecological proces- ses. INTERACTIONS BETWEEN SCORPIONS AND SPIDERS ON ISLANDS IN THE GULF OF CALIFORNIA This system shows several of the same general processes as the one on Acacia trees in the Namib and illustrates the importance of predator-prey interactions occurring between spatially struc- tured populations. Spider, scorpion and/or lizard populations on small islands (approximately <1km*) are 1-3 orders of magnitude more dense than on larger islands (approximately 1- 1000km*) and the mainland; si ignificant negative relationships occur between island size and den- sity for each of these taxa. For example, the scorpion Centruroides exilicauda is 2-25 times more abundant on small islands. Three major variables likely explain the great variance in spider abundance; 1) the presence of scorpion predators (often absent from small islands): 2) the dispersal and colonizing ability of spiders relative to scorpions (better colonizers of small islands as. compared to scorpions); and 3) differential ener- gy flow from marine to terresirial systems (much ereater to small islands). This research has been in progress for four years (1989-1992) in the Midrift area of the Gulf on 41 island and 6 mainland sites between Bahia de Los Angeles (Baja Califomia del Norte, Mexico) and Guaymas (Sonora, Mexico) (Polis unpublished). Scorpion and spider abundance were quantified at each site: spiders were counted on >4000 cacti (one sample unit) and >8000m* of supralittoral shoreline (another sample unit). In- sect abundance was estimated at these sites for > 1000 trap days. Small islands ( Ura lizards> Scorpions> Nest predators >Songbirds, Colonization would be deterministic if particular taxon were always present or absent for all islands ofa particular size class. In fact, incidence values for smaller island size classes are neither 0 nor 100%, suggesting that presence or absence of a particular laxon is somewhat stochastic. Thus some small islands exhibit high densities of spiders because scar- pions are absent whereas other similar sized is- lands exhibit Jow densities of spiders because SCOrpions are present. An integration of colonizing abilities, produc- 199) duis with lizards Regression fs fx25- Inara —_ aes | | iz ae Scorpion presence 90559] Lispnsene || [eacus voume ||) nab Izonn [Tora thismodet=070| | | | 199} dete with fizards [uf SS [MS |P Regression 33.43 [1.09 [11.01 | 0.0008, Exfor wisi loo | | | [rot tas | Penmeter: Arta |] Jae | 0.0083 } (Scorpionpresence | | | ~—_—*S.80_| 0.00985 | [Lizwrdpresence | | S| (3.78 _| 0.9687) aetannala— Lti TABLE 6. Multivariate regression of factors that may influence spider abundance on islands in the Gulf of California in 1990 and 1991. The maximum R im- provement technique is used; this produces the best model given ull the independent variables. Inde- pendent variables include lizard presence, scorpion presence, perimeter: area ratio of island, mean cactus volume/istand and prey availability/istand, The best two Variable model includes perimeter: area ratio and scorpion presence. Three variable models are presented with lizards. The effect of lizards is always non-significantly weak, regardless of what higher order model is used. MEMOIRS OF THE QUEENSLAND MUSEUM fivity and predation is required to understand the distribution and abundance of these taxa. Each factor varies more of less regularly with island size: generally, as size increases, secondary productivity decreases, predation increases and the importance of differential colonizing ability diminishes. Multivariate analysis allows statisti- cal dissection to determine the relative contnibu- tion of each of these factors to the observed Vanance in spider density. This analysis (Table 6) shows that spider density is 4 significant positive function of prey availability and significantly depressed in the presence of scorpions. Arthropodivorous lizards are a seemingly unim- portant factor, explaining almost none of the variance in spider abundance on Midrift islands. In summary: Productivity sets potential maxi- mal population size. Small islands are much more productive than larger islands because of the rela- live greater input of marine allochthonous productivity from drift and marine birds, Colonizing ability establishes the insular species combinations; species-area relations show that larger islands are more diverse and support more types of predators. The realized abundance of terrestrial taxa is limited by (intraguild) preda- tion. For example, if scorpion predators are ab- sent, spiders are dense on small, high productivity islands. When scorpions are present, spider den- sity is lower (but still higher than on large islands and the mainland) and the density of scorpions is relatively high. As island size increases, produt- tivity decreases because nest predators are present (thus bird colonies disappear) and alloch- thonous detrital input decreases as a function of island Perimeter : Area ratio. Eventually, as is- Jand size increases (with decreases in produc- uvity and increases in predation), the abundance of spiders, lizards and scorpions decreases until abundance on very large islands approaches that of the mainland. Strong predation from many sources occurs on the relatively low productivity mainland; consequently, populations of spiders, scorpions and lizards are quite low. CONCLUSIONS This paper presents various types of data to evaluate the ‘ecological importance’ of scorpions in deserts. Ecological importance was first con- sidered in terms of population energetics (the quantity of energy and mass flowing through scorpion populations) and second, in terms of the regulation of community structure and dynamics (how imtraguild predation by scorpions influen- SCORPIONS AS MODEL VEHICLES ces the distribution and abundance of their com- petitors/prey). The energetic analysis provided three conclusions: 1) Scorpions are quite diverse and abundant in deserts, They monopolize a rela- tively large share of animal biomass in desert communities, particularly relative to vertebrates aml other arthropods. 2) Their relative success is due to a suite of autecological traits that are particularly suited to the harsh and vanable climatic conditions of deserts. These traits (very low metabolism and very high assimilation ef- ficiency leading to low energy requirements: and freat tolerances to water stress, heat and starva- tion) preadapt ther to prosper successfully under the unpredictable and low productivity food availability that characterize deserts. 3) However. these traits (low metabolism and high assimila- lion efficiencies) lessen their impact on ener- getics, prey and competitors. Thus the importance of scorpions relative to homeother- muc vertebrates is Jess than an analysis of density arm biomass suggest because scorpions require and process prey in quantities relatively low to their biomass. Nevertheless, as a group, Scorpions are probably important conduits of energy flaw in deserts. The research on the interactions among scor- pions and that between scorpions and spiders strongly suggests that scorpions can play key roles in the structure and dynamics of the com- munities in which they live. These studies showed that intraguild predation by scorpions was a major force determining the (temporal and spatial) distribution, abundance and age structure of populations of their competitors/prey. How- ever, a8 an important caveat, these interactions must be viewed in the context of the environment in which they occur. Dispersal ability, spatial structure and productivity are just some of the possible important factors that moderate the predator-prey interaction between scorpions and their intraguild prey. The role of all ecologists is to integrate these factors to produce a synthetic understanding of the processes and dynamics that structure natural communities. I suggest that scorpions are pur- ticularly suited for this task and will continue to be a productive vehicle to advance the theoretical and empirical body of ecology. ACKNOWLEDGEMENTS This paper highlights the results of 10-15 years of scorpion research. It is impossible to thank individually all the wonderful people that have contnbuted their time and energy to this work. Key colleagues include Sharon McCormick, Mary Seely, Steve Hurd, Rick Fleet. Mike Qin- lan, Tracey Wadsworth, Victor Fet, Chris Myers, Denise Due, Tsunemi Yamashita and Sharon Lee-Polis, Bill Humphreys’ careful reacting has improyed this paper greatly, | thank the fine stalf at the Queensland Museum [especially Robert Raven) and the Western Australian Museum for orchestrating such a great congress and for providing suppor for my attendance, LITERATURE CITED BRADLEY, R.A. 1983. Complex food webs and manipulative experments in ecology. Oikos 41: 150-152. 1986. The relationship between populavon density of FPeruroctonus utahensis (Scorpionida: Vaejovidae) and characteristics of its habitat, Journal of Arid Environments | 1: 165-171. 1988. The influence of weather and biotic factors on the behaviour of the scorpion (Parurnctome 1 pais Journal of Animal Ecology 57; 533- 1. DUE, A.D. & POLIS, G.A. 1985. Biology of the inter- tidal scecpion, Vaejovis lineralis. Journal of Zoe- ogy 207: 563-380, 1986. Trends in scorpion diversity along the Baja Cahforma peninsula. American Naturalist 1238; 460-468. HUMPHREYS, W.F, 1979, Production and respiration in animal populations. Journal of Animal Ecology 48: 427-454, LAMORAL, B. 1978. Soil hardness, an important and limiting factor in burrowing scorpions of the genus Opisthophthalmus C.L. Koch, 1837 (Seor- pionidae, Scorpionida). Symposium of the Zoologi¢al Society of London 42: 171-181. MARPLES, T.G. & SHORTHOUSE, DJ. 1982. An energy and water budget for a population of arid zone scorpion Urodacus yaschenkoi (Birula 1903), Australian Journal of Ecology 7: 119-127, MCCORMICK, S.J. & POLIS, G.A, 1990. Prey, predator: and parasites. 294-320, In Polis, GA, (ed,) "Biology of Scorpions’. (Stanford University Press: Stanford, California). POLIS, G.A. 1980a. The significance of cannibalism ars the population dynamics and surface activity of a natural population of desert scorpions. Behavioral Ecology and Sociobiology 7: 25-35, 1980b, Seasonal and age specific variation in the surface activity of a population of desert seer- pions in relation to environmental factors, Jour- nal of Animal Ecology 49; 1-18 1981. The evolution and dynamics of intraspecific predation. Annual Review of Ecology and Sys- lemiilics 12: 225-251. 1984a. Age structure component of abche wadih and intraspecific resource parlilioning: can age 410 groups function as ecological species? American Naturalist 123: 541-564. 1984b. Intraspecific predation and “infant killing” among invertebrates. Pp. 87-104. In Hausfater, G. and Hardy, S. (eds). ‘Infanticide: Comparative and Evolutionary Perspectives’. (Aldine Publ. Co.: New York). 1988. Exploitation competition and the evolution of interference, cannibalism and intraguild preda- tion in age/size structured populations. 185-202. In Persson, L. and Ebenmann, B. (eds), ‘Size Structured Populations: Ecology and Evolution’. (Springer-Verlag: Heidelberg). 1990. Ecology. Pp. 247-293. In Polis, G.A. (ed.), ‘Biology of Scorpions’. (Stanford University Press: Stanford). 1991a. Complex trophic interactions in deserts: An empirical critique of food web theory. American Naturalist 138: 123-155. 1991b. Desert communities: an overview of patterns and processes. Pp. 1-26. In, Polis, G.A. (Ed), ‘The Ecology of Desert Communities’. (University of Arizona Press: Tucson). POLIS, G.A. & FARLEY, R.D. 1980. Population biol- ogy of a desert scorpion: survivorship, micro- MEMOIRS OF THE QUEENSLAND MUSEUM habitat, and the evolution of life history strategy. Ecology 61: 620-629. POLIS, G.A, & MCCORMICK, S.J. 1986a. Patterns of resource use and age structure among species of desert scorpions. Journal of Animal Ecology 55: 59-73. 1986b. Scorpions, spiders and solpugids: predation and competition among distantly related taxa. Oecologia 71:111-116. 1987. Intraguild predation and competition among desert scorpions. Ecology 68: 332-343. POLIS, G.A., MYERS, C.A. & HOLT, R. 1989. The ecology and evolution of intraguild predation: potential competitors that eat each other. Annual Review of Ecology and Systematics 20: 297-330. POLIS, G.A, & YAMASHITA, T. 1991. The ecology and importance of predaceous arthropods in desert communities. Pp. 180-222. In Polis, G.A. (ed.), ‘The Ecology of Desert Communities’. (Univer- sity of Arizona Press: Tucson). SHORTHOUSE, D. 1971. Studies on the biology and energetics of the scorpion, Urodacus yaschenkoi (Birula, 1904). (Ph.D. dissertation, Australian Na- tional University: Canberra). INTER-SPECIFIC ASSOCIATIONS INVOLVING SPIDERS: KLEPTOPARASITISM, MIMICRY AND MUTUALISM MARK A. ELGAR Elgar, M.A. 1993 11 11: Inter-specific associations involving spiders: kleptoparasitism, mimicry and mutualism. Memoirs of the Queensland Museurn 33(2). 411-430. Brisbane. ISSN 0079-8835. Many spiders have life-styles that involve a relatively close and prolonged association with another species; for example, between a specialist predator and its prey species, or a species may rely on another for either protection from predators or providing a suitable place to live. In asymmetric relationships, where individuals of one species benefit at the expense of the other, each species may acl asa selection pressure on the other species. This can resultin the evolution of specific adaptations and counter-adaptations that are evident i at least three kinds of inter-specific associations between spiders. These associations, namely klep- toparasitism, mimicry and mutualism are reviewed here. Our understanding of the evolution of these fascinating systems remains limited, despite numerous anecdotal accounts, because only a few studies are expenmental. The purpose of this review ts two-fold: to illustrate the use. of comparative and experimental studies for understanding the evolutionary significance of these inter-specific relationships, and to highlight those gaps in our knowledge that might benefit from this approach.[/nter-specifiec associations, spiders, kleptoparastiism, mimicry, mulwalism. Mark A. Elgar, Department of Zoology, University of Melbourne, Parkville, Victoria 3052, Australia; 18 January, 1993, Individuals of one species can affect in- dividuals of another as. a result of competition, predation, parasitism or mutualism, The evolu- tionary implications of any association between two or more species depends critically on the frequency and nature of the interaction. For ex- ample, a species may be the prey of many species of generalist predators. While these predators may represent an important selective pressure favouring anti-predator responses in the prey species, the adaptations of the prey may have little impact on the reproductive success of the predators. In contrast, a predator that preys on only one species can be an important selective force favouring anti-predator adaptations in that species. In turn, the prey species anti-predator adaptations can exert a selective pressure on the predator, favouring improved predatory abilities. Thus, each species acts as a selection pressure on the other, favouring adaptations and counter- adaptations, perhaps leading to characteristics that are increasingly specific to the relationship. However, these improvements need not neces- sarily change the relative position of each protagonist (Dawkins and Krebs, 1979). The evolution of these specific adaptations and counter-adaptations depends on both the frequen- cy of the interactions and the effects of each protagonist, Host- parasite systems provide a rich seam of examples of such evolutionary processes (e.g. Endler, L986; Davies ef al., 1989; Toft eral, 199}), but there is also some evidence for similar processes in predator-prey systems (e.g. Brodie and Brodie, 1991; Endler, 1991). INTER-SPECIFIC ASSOCIATIONS IN SPIDERS Research on the behaviour and ecology of spiders has, with a few notable exceptions, focussed on issues involving single species (e.g. Humphreys, 1988), including foraging behaviour (Reichen and Luczak, 1982; Vollrath, 1987a; Uetz, 1992), habitat choice (e.g. Reichert and Gillespie, 1986), intraspecific competition (e.g. Reichert, 1982), courtship and mating (e.g. Robinson and Robinson, 1982; Elgar, 1992) and social behaviour (Buskirk, 1981; Elgar and Godfray, 1987; Uetz, 1988). Nevertheless, some spiders have relatively specific and prolonged relationships with other species. These relation- ships ofien involve predation or avoiding preda- tion, and perhaps a reason why inter-spevific interactions involving spiders have been neglected is that spiders are frequently perceived as generalist predators; cursonal or wandering spiders attack any vulnerable prey that they can find, while web-building spiders simply capture any prey thatis cayghtin their web. However. the view that spiders are generalist predators is mis- ale leading. Many spiders prey on only a few species. using foraging techniques that include building specialised webs; producing chemical com- pounds that attract prey; utilising the webs or capturing capabilities of other spiders: mimick- ing prey behaviour; and cooperative foraging (see reviews in Stowe, 1986; Nentwig, 1987). Clearly, the survival and reproductive success of both predator and prey will depend on their predatory and defensive behaviours, and the degree to which the predator depends on the prey as a source of food. Not all associations between spiders and other invertebrates are predator-prey relationships; some species depend on other species for protection [rom predators, or provid- ing suitable places to live, This review will focus on three interspecific relationships involying spiders: kileptoparasitism. mimicry and mutualism. A detailed understanding of the nature of these inler-specific associations wall bencfit fram both experimental and comparative studies. The former can provide insight into both the fitness effects of the association on individuals of cach species, and the importance of particular species’ uaits for maintaining the association. Compara- live studies can provide further insight into the selection pressures responsible for the evolution of the association; reveal the implications of these associations for other aspects of the species life- history charactenstics; and help formulate ideas that can be subsequently examined experimental- ly (see Harvey and Pagel, 1992 forreview). While emphasising the evolutionary dynamic nature of inter-specific associations, a central theme of this review is to illustrate the use of comparative and experimental studies for understanding these sys- tems, and also to highlight those gaps in our knowledge of arachnid inter-specific associations that might benefil from this evolutionary ap- proach. KLEPTOPARASITIC ASSOCIATIONS The webs of spiders are host to numerous in- sects, including flies, damselfies and wasps (see reviews in Vollrath, 1984, 1987b; Nentwig and Heimer, 1987). Mast descriptions of these guests are anecdotal, and consequently the nature of the relationship is poorly understood, The webs of many spiders are also host to numerous other spiders that obtain food from prey caught in the host's web. These spider guests, commonly referred to as kleptoparasites, are represented in at least four families, including the Dictynidae, MEMOIRS OF THE QUEENSLAND MUSEUM Mysmenidae, Symphytopnathidae and Theridiidae (Table 1). Of these spiders, the genus Argyrades (Theridiidae) is the best documented (see Vollrath, 1984, 19875). Evipence oF KLEPTOPARASITISM Argyrodes were originally described as com- mensals: Argyrodes benefit by feeding on the prey items that are caught in the host’s web, but the host is not disadvantaged hecause these prey items do not form part of its diet (e.g. Belt, 1874). However, subsequent behavioural and ecological studies revealed that individual Argyrodes remove prey that might otherwise be consumed by the predator. These observations suggesi that the relationship between Argyrodey and their hosts is more accurately described as klep- loparasilic rather than commensal (see Vollrath, 1984, 1987b). Th fact, kleptoparasitism may also be an inap- propnale descnption. A kleptoparasitic relation- ship implies thal one partner in the symbiosis henetits at the expense of the other, and that the kleptopurasite has certain characteristics that are adaptations to this lifestyle. Studies of several species associations leave little doubt that the latter contention is correct. Forexample, the sym- phytognathid Curimagua bayane inhabits the webs of a large mygalomorph Diplura, enher climbing about the funnel web or remaining on the host (Vollrath, 1978). After 4 Diplura has caught, masticated and enveloped a prey item in digestive fluids, the kleptoparasite descends to the prey item and imbibes the liquidized prey. Interestingly, the anatomy of the mouth of C. bayano apparently prevents it from being able to capture, hold or masticale its own prey, suggest- ing itis an obligate kleptoparasite (Vollrath, 1978), Several behaviours of Argyrodes appear to be adaptations that are specifically related t their kleptoparasitic lifestyle. These spiders can move throughout the web, apparently undetected by the host, and the attempts of the kleptoparasites to obtain prey items may vary according to the behaviour of the host (Vollrath, 1984, 1987b). There are several mechanisms by which klep- toparasitic Argyrodes avoid detection or capture by the host: many species drop from the web when challenged by the host, A. antipovdianus swings away trom the web when the host is agitated (Whitehouse, 1986), and A. ululans cuts holes in the tangle web of its social spider host Anelosimus eximias, forming a tunnel that ap- parently facilitates escape (Cangialosi, 1991). INTER-SPECIFIC ASSOCIATIONS Surprisingly, the evidence that the presence of Argyrodes has a negative effect on the reproduc- tive success of the bast has not been directly assessed, For example, there are no experimental evidence that the growth rate or fecundity of the host is reduced by the presence of Argyrodes (ar any other genera of Kleptoparasites). Instead, the negative impact of Argyrodes on its host has been inferred primarily from either the behaviour of the host (eg. Larcher and Wise, 1985}, or from estimales of the energetic costs denved from the loss of prey items obtained by Argyrodes. For example, the number of prey items consumed by Nephila clavipes is reduced with increasing num- bers of Argyrodes on the web (Rypstra, 1981), and A. wlulans removes around 26% of the prey items that are capght in the web of its hosi Anelosimus extmius (Cangialosi, 1990b), Vollrath (1981) examined the potential costs of Argyrodes by estimating the energetic tequire- ments of a single kleptoparasite. The daily energy requirements of the 3-4 mg A. élevares is 0.82 J, about 0.5% of the daily requirements of its 973me2 (Nephila clavipes) host, This proportion in- creases with larger numbers of kbeptoparasites per web; over 40 individuals have been counted on asingle Nephila web (although the average is 2.2 kleptoparasites per web), suggesting a poten- ually high energetic cost of this relationship (Vollrath, 1981). If kleptoparasites exact a cost on host reproduc- live success, then selection should fayour any trait that enables the hosts to reduce that cost. There are several mechanisms by which hosts might reduce the cost of kleptoparasttism: recovering the prey from the kleptoparasite; reducing the kleptoparasites access to the prey; or simply abandoning the web and building another elsewhere. Interestingly, hosts appear to be inet- ficient at recovering prey (Vollrath, 19792, b; Kypstra, 1981) although several host species reduce access to their prey by chasing the klep- loparasites (Cangialosi, 1990b) or concealing the prey in retreats (see Cangialosi, 1990b). Larcher and Wise (1985) demonstrated experimentally that hosts are more likely to abandon webs when Argyrodes are present than absent. Nephila clavipes relocates ils web when itis infested with Jarge numbers of kleptoparasites (Rypstra, 1981), although the behaviour of NV. clavipes may be a response to lower feeding rates, rather than to numbers of kleptoparasites, Social or communal spiders appear to have fewer defensive options against high klep- toparasite loads, and this cost may be higher if the 413 number of kleptoparasites per web is greater in larger colonies. For example, Nephila edulis builds webs in aggregations, and webs in ag- gregations have higher kleptoparasite loads and infestation rates than those found alone (Elgar, 1989), Re-locating a web away from an aggrega- tion may reduce kleptoparasite load. but the hast subsequently does not benefit from the foraging and predator defense advantages of living within an aggregation (e.g. see Uetz, 1988), Moving web sites to reduce kleptoparasile load may oot be possible for some socjal spiders, such as Anelosimus that build substantial, permanent webs, Indeed, high kfeptoparasite loads are apy parently responsible ter the demise of some Anelosimus colonics (Cangialosi, 1990bh) but nor others (Vollrath, 1982). Like their hosts, individual kleptoparasites may also react to variation in prey capture rates. The feeding rates of kleptoparasites are likely to he influenced by both the prey capture rate of the host and the number of other kleptoparasites on the web. Host web capture rales may vary accord. ing to both the location and the size of the web. The number of kleptoparasites increases with the web size of several hast species (e.g, Elgar, 1989; Cangliosi, 1990a), possibly because larger webs have higher web capture rates that can support more kleptoparasites, Web-building spiders relo- cate their webs according to prey capture rates (e.g. Gillespic and Caraco, 1987), and Argyrades may behave similarly by moving to different webs (but see Larcher and Wise, 1985). it would be interesting to establish experimentally whether the emigration rate of individual Ar- gyrodes increases as a result of lower web capture rates Or increased numbers of conspecifics. If the latter, it as possible that the distribution of Ar gyrodes within a population of hosts, particularly those hosts that aggregate, could be predicted by the ideal free distribution (see Milinski and Parker, 1991), A possible option fer kleptoparasites that ex- perience a low feeding rate is te capture and consume the host before moving to the web of another host (e.g. Tanaka, 1984). Some specics of Argyrodes are either obligate or facultative predators of their hosts (see Table 1), Predatory Argyredes can capture the host through mimick- ing aprey item (e.g, Whitehouse. 1986) or simply advancing toward the host and attacking it. Such a specialised form of predation is net uncommon in spiders. and has been recorded in several families (c.g. Jackson, 1987; Jackson and Bless, 1982; Jackson and Brassington, 1987, Jarman MEMOIRS OF THE QUEENSLAND MUSEUM TABLE 1: Spiders that are ‘eseinielt te to be kleptoparasites of web-building spiders. Families: Ag, Agelenidae; Am, Amaurobiidae: Ap, Aphantochilidae; Ar, Araneidae; Cl, Clubionidae; Co, Corinnidae; De, Deinopidae; Di, Dipluridae; Er, Eresidae; Gn, Gnaphosidae; Lin, Linyphiidae; Lio, Liocranidae; Ph, Pholcidae; Pro, Prodidomidac; Sa, Salticidae; Td, Theridiidac; Tm, Thomisidae; Ul, Uloboridae; Zo, Zodariidac, Agg, Ag- eaaies Soc, Social; Sol, Solitary, Web types: O, orb; T, tangle: S, sheet; F, funnel; Sp, space.Body sizes in Boiysie | Host, ues | sto Kleptoparasitic taxa Whee Source epopricusa [Family [Species [Size [Web _[Sociai| Pe" ¥*P Archaeadicryna ulova Griswold & Meikle- ee a ee O. sp. indet, O, lamareki a faatimancondide __| |r [soe [ra _}x_[ustsont.9e77_ Stegodyphus sarastnorum [soc _[10 [Kk [Sackson(1987)___| rine cobs [| [er [Sesion [Ise [x [oso ie) | tatstwcod [Tt [aes [fT lp | | | [Kitifiximguitina | | id Thelechoriskarsehi Myvmenopsisarcheri| | [ph | M. capue Ph || dar [M.cidreticola (| | foi M_cienga M. dipluroamiga M. M. M. hauscar urtiva gamboa M. manticola M. pachucutec M: palpalis AM, rihvalis M, sp. indet. Donopidae Cyrtophora Diplara ischnothele sp Co leetal. 1991) = eee | jo | | | a | [Ac |Cyriophora | S| ST [fis [| [ {x | Vollrath (1978) [Di |fichnothelexera | s(t _—‘[sol_[i4 ([K __| a ea a Vollrath (1978) K K Ce CC SCT pi fiwrumiemn | frst |p Po for TK cyte erat. 9g Po oye et at (1992) Poe Pf i | [oi [iscimortetereggae | | TK [Coyle erat. (1991) K Baert (1990) Coyle ér al. (1991) Baer (1990) Coyle ei al. (1991) Coyle e/ al. (1991) Coyle & Meigs 1989 Coyle etal. (1991) Oonapspulcher 20 [1s [Am [Amaurobinsfenesratis |e |v | | | K | Bristowe (1958) Salticidae Badwnna candida = = [xP [Jackson (1985) Symphytognathidae 13 Theridiidue 7 Argyrodes antipodianus [A-annipodionus |_| |_| A. antipodianus A. unitipodianus A. antipedianus Di Diplura sp. Cambridgea sp. Is | sol Stiphidian Badunmna longinguus A. antipadianus A. untipodianus A. untipodianus Td A.antipodianus | | ra aeanipodians _[30_a.s_ [A.antipodianus [30 |25 [Ar [Nephil edubs [21 | 3.0 Araneus crassa Sol Eriophora pustulosa Cyclosa trilobata Leucauge dramedaria Pholcus phalangioides K (8) Sol Oo Sol Q Sol Achaearunea T lar [Cyrophorahina tao [sor | [K a1 Jo Tage | [| etgar (1989) KP K Vollrath (1978) f_fsa_| _Txe Whitehouse (19884) Whitehouse (19883) KP. Whitehouse (19883) Whitehouse (19883) Whitehouse (19884 Whitehouse (1988) so | ter | Whitehouse (19883) Whitehouse (1988 a) Elgar er al, (1983) INTER-SPECIFIC ASSOCIATIONS 415 Pe, Body size Guests | Assoc Kleptoparasitic taxa [Body size _| S “ ee ee ead A. argyrodes a Cyrtophora citricola Vollrath (1984) A, atopus 2.4 3.4 Nephila clavipes Eo g |5 K Vollrath (1987) A. attenuatus 17.0 Eberhard (1979a) A. babowsiinart 37 Latrodectus es & Levi A. baboquivari 3.7 3.5 Ul Philoponella oweni Agg | KP Smith Trail (1980) A. cancellatus 32 3.8 Ag Agelenopsis F K (1963) celevs A, cancellatus 3.2 3.8 Ar Argiope aurantia 22 oO K IED} cas i A. cancellatus 3.2 3.8 Ar Araneus strix oO K (196a5 Be Levi A. cancellatus 3.2 3.8 Ar Mecynogea lemniscata Oo K (1960) elev A. cancellatus 3.2 3.8 Ar Metepeira labyrinthea oO Sol K (1963) STev A. cancellatus 3.2 3.8 Ar Nephila clavipes 25 oO Agg K AiOED & Len A. cancellatus 3.2 3.8 Ar Verrucosa arenta 9 oO K ti96d} elev A. cancellatus 3.2 3.8 Li Frontinella pyramitela K riDER ee T A 3 A. cancellatus 3.2 3.8 Ph Pholcus space | Sol K (1963) Solent A. cancellatus Theridion tepidariorum reas oe A. caudatus Argiope argentata Smith Trail (1980) A. cochleaforma A 2.7 3.7 Ar Argiope Exline & Levi (1962) Table 1. continued . cochleaforma Gasteracantha oO K C1863) f Levi A. colubrinus 25.0 none Eberhard (1986) A. cordillera Gasteracantha oO K 196% Se Levi A. cylindratus Araneus ventricosus (0) Sol K Shinkai (1988) A. dracus Nephila clavipes 25 [0 [Age Vollrath (1987) A. elevatus 3.4 Argiope argentata 16 Oo K Vollrath (1979) Exline & Levi A. elevatus 3.4 4.0 Ar Gasteracantha Oo K (1962) A, elevatus 3.4 4.0 Ar Nephila clavipes 9) A 5 _|K Vollrath (1979 A. fictilium 10.0 |5.0 |Ar — |Araneus fe) KP os & Levi A. fictilium 10.0 |5.0 Li Frontinella communis 4 S Age KP Wise (1982) A. fictilium 10.0 [5.0 [ul | Philoponelia oweni 6 lo [Age |__| KP [Smith Trail (1980) A. fictilium 10.0 EG & Levi A, fissifrons 7.0 Agelena limbata Tanaka (1984) A. fissifrons 7.0 Linyphia Tanaka (1984) A. fissifrons 7.0 Theridion japonicum T KP Tanaka (1984) A, fissifrons 7.0 Ul Philoponella sp. 3 Oo Age |3 KP Elgar (pers obs) A. fissifrons 7.0 Ul Uloborus varians oO KP Tanaka (1984) A. flagellum [| fnone _ | PTT berhara (1986) A. globosus Nephila clavipes Age | Hoke, & Levi A. incisifrons Cyrtophora hirta Sol K Elgar et al. (1983) 416 Table 1. continued Kleptoparasitic taxa A. incursus A. longissimus Social MEMOIRS OF THE QUEENSLAND MUSEUM Guests per web Assoc Source 5 KP Gray & Anderson (1989) Exline & Levi (1962) A, miniaceus Nephila maculata Robinson & Robinson (1973) A. nephilae Argiope Exline & Levi (1962) A. nephilae 1.7 Dis Ar Cyrtophora moluccensis _|19 Oo Agg K Berry (1987) A. nephilae 17 2.2 Ar Gasteracantha Oo K Cpe a Levi A. nephilae 1,7 2.2 Ar Neoscona oO K fen & Levi A-nephilae 17 |22 |Ar [Nephi re) K | hones & Levi A, nephilae Ar Nephila maculata 43 oO K oa O78) Argiope aurantia K Hoes} Sc Lew A. pluto 3.9 3%, Ar Metepeira labyrinthea oO Sol K en & Levi . i A, pluto 39 13.7 |Td — |Latrodectus T= [sol K fae) & Levi A. proboscifo 2.6 2.9 Ar Gasteracantha oO K Giesy & Levi = A. projiciens 4.0 3.2 Ar Metazygia sp. oO Sol KP Eberhard (1986) A. sp. A Ar Nephila clavipes 25 oO Age |2 K Rypstra (1981) A, sp. B Ar Cyrtophora moluccensis | 19 lo Agg KP Lubin (1974) A. sp. C Ar Gasteracantha Oo 23 Vollrath (1981) A. subdolus 2.6 2.8 Ul Philoponella oweni 6 Oo Agg K Smith Trail (1980) A. trigonum 4.2 2.5 Ag Agelena limbata 16 F Agg KP Suter et al. (1989) A. trigonum 4.2 ey Ag Agelenopsis F oy SeLevi A. trigonum 4.2 2.5 Ar Mecynogea lemniscata Oo KP Wise (1982) A. trigonum 4.2 2.5 Ar Metepeira labyrinthea oO Sol KP Cio) Wise: A. trigonum 4.2 Bd Lin Linyphia marginata 5 S KP Fading sey (1962) A. trigonum 42 |2.5 |Lin | Neriene radiata 5 s_ |Sol KP ‘ee & Wise A. trigonum 4.2 2.5 Td Latrodectus T Sol (1963) shel A. trigonum 4.2 Theridion zelotypum 4 \t KP ae & Levi A. trigonum Frontinella pyramitela 4 Ss KP Suter et al. (1989) A. ululans 4.0 Nephila clavipes 25 Oo Age K Exline & Levi (1962) A, ululans Anelosimus eximius [ T Soc K Cangialosi (1990a) “A; wavrauichi Exline & Levi sais (1962) “Two categories of relationship (‘Assoc’) are defined: ‘K’ is Kleptoparasite only, and ‘KP’ means that the guest may also capture the host. Some species of Argyrodes may be incorrectly categorised as ‘Kleptoparasite only , because their predatory behaviour has not yet been observed. Taxonomy of Argyrodes follows Levi and Exline (1962) and thus Argyrodes, Ariamnes and Rhomphaea are not distinguished. INTER-SPECIFIC ASSOCIATIONS —— Klepuoparasite i pe fier [atsaz6 | errr Hos TABLE 2: Differences in kleptoparasite and host body length according to whether the kleptoparasite does or does noi also prey on their host. Values are mean lengths + SE (sample sizes), Values compared using Ltest with pooled variance. Average host body size measures were obtained for Argyrodes that have multiple hosts. * p< 0,05; ** p < 0.005, and Jackson, 1986: Jackson and Hallas, 1990), A potential cost of this foraging strategy is that the kleptoparasite may become prey to the host. At least one host species has a relatively effective defensive behaviour: when the predatory Ar- gyrodes is detected, the host simply cuts the web thereby collapsing it and ensuring that the predator cannot proceed further (e.g. Eberhard, 1979b), Suter et al. (1989) report jhat female F. pyramitela can discriminate between conspecific males, prey items and predatory A. Irigonum, apparently using chemical cues, and respond ac- cordingly. COMPARATIVE PATTERNS. WITHIN ARGYROiES What evolutionary sequences. are responsible for the diversity of predatory specialisations in Argyrodes? Smith Trail (1980) stresses the im- portance of the kleptoparasites’ ability to identify the vibratory signals generated by the host, thus allowing them to stalk and safely capture the host. However, kleptoparasites that also altempt to capture their hosts nsk being captured themsel- ves. Consequently they may be more likely to attempt to capture vulnerable hosts, such as those that are smaller (e.g. Smith Trail, 1980; Larcher and Wise, 1985), moulting (e.g. Vollrath, 1984), of even the spiderlings of the host (e.g. Whitehouse, 1986). Ifrelative body size1s mmportunt in determining the outcome of attacking the host, then predatory species of Argyrodes may be larger than primaci ily kleptoparasitic species, or the former may tend to specialise on smaller hosts. These predictions are supported by comparative data of body length measures for 20 species of Argyrades (see Table 1). Species of Argyrodes were divided inio two groups, according to whether they preyed on their hosts: females of Argyrodes that are only klep- toparasitic are significantly smaller than those 417 that also prey on their hosts (Table 2). However. males of these two groups of species are not significantly different in body size (Table 2). Argyrodes that prey on their hosts also specialise on smaller hosts, compared with the size of the hosts of those species of Argyrades that are only kleptoparasites (Table 2). These comparative data show that, as predicted, the difference in size between Argyrodes and its host ts greater for those species that are primarily kleptoparasitic compared with those that are also predatory These comparative data suggest that selection has either Favoured larger body size for species that are both kleptoparasitic and prey on their hosts, of it has favoured a further reduction in body size in those Specics thal are primarily kKleptoparasitic. The hitter argument is consistent with the view that kleptoparasitism is a specialised foraging strlegy that evolved from a more general klep- toparasitic and predatory lifestyle (Vollrath, 1984), The evolutionary sequence leading to the diver- gence of these two foraging strategies within Argyrodes is not known; one may have evolved from the other, or both may have diverged from a common web-building ancestor (see Whitehouse, 1986). Thus, it is not possible, without an accurate phylogeny, to establish whether selection has favoured an increase in body size with the predatory hfestyle, or a decrease in body size 1s associated with 2 klop- toparasitic lifestyle, Indeed, the species placed within the single genus Argyrodes by Exline and Levi (1962) have been placed by others into three genera; the Ariamnes, the Rhamphaea, und the. Argyrodes, In this classification, the Ariamnes and Rhomphaea groups are primarily host- predators and the Areyrodes group are klep- toparasites (Whitehouse, 1987), Thus, the differences described above may be confounded by taxonomic associations (see below), Resoly- ing some of these issues is most likely achieved by experimental manipulation of individuals within a species that shows both kleptoparasitic and predatory behaviour. An additional pattern revealed by comparative analysis ulso deserves experimental invesligu- tion. The degree of sexual size dimorphism (male length/female length) covaries significantly with the foraging strategies of Argyrades, Males are smaller than females in those species that prey on their host, consistent with pattems of size dimor- phism in almost all other spiders (e.g. Elgar et al. . 1990; Elgar, 1991, 1992; Vollrath and Parker, 1992). However, males of those species of Ar- 418 Kleptoparasite* Agelenidae Agelena (2), Agelenopsis, Cambridgea, Stiphidion Amaurobiidae Argyrodes (4) Simaetha, Badumna (2) Argyrodes Amaurobius Oonops Araneidae Araneus (5), Argiope (4), Cyclosa, Cyrtophora (2), Gasteracantha, Leucauge, Mecynogea, Metazygia, Metepeira, Neoscona, Nephila (3), Verrucosa Argyrodes (18) Cyrtophora Mysmenopsis (2 Dipluridae Allothele Isela Diplura, Ischnothele Mysmenopeis Diplura Thelechoris Linyphiidae Frontinella (2), Linyphia, Neriene Pholcidae Pholcus Pholcus‘ Theridiidae Achaearanea, Theridion (3), Anelosimus, Latrodectus Uloboridae Uloborus, Philoponella TABLE 3: Summary of taxonomic distribution of spiders that are host of kleptoparasites (see Table 1 for further details). KP= Kleptoparasites and predators; K=kleptoparasites. * No. species in each genus in parentheses. gyrodes that are primarily kleptoparasitic are generally larger than their conspecific females (see Table 2). What factors are responsible for this reversal of size dimorphism patterns within this group of spiders? One explanation is that competition between males for access to females may be more intense for kleptoparasitic spiders, and consequently sexual selection has favoured large male size in these species (see also Whitehouse, 1988b). There is considerable variation in both the num- ber of species that are host to each species of kleptoparasite and the number of kleptoparasite species found on each web-building host species (see also Vollrath, 1984, 1987b). For example, Argyrodes cancellatus are found on the webs of at least ten different host species from five families (see Table 3), while the orb-weaver Nephila clavipes is host to at least seven species MEMOIRS OF THE QUEENSLAND MUSEUM t statistic 2.80.7 3.5413 1.89 0.57 | 2.7+0.7| TABLE 4: Mean host-ranges of Argyrodes that are either only primarily kleptoparasitic or they also prey on their host.* refers to Argyrodes. of Argyrodes. It is likely that both host-range and parasite-range will expand as more records be- come available. In contrast, many species appear to be host specific, with one species of klep- toparasite recorded from the web of only one species of host. For example, in certain Peruvian habitats, Argyrodes ululans is found only on the webs of the social spider Anelosimus eximius, despite considerable effort searching for this kleptoparasite on other potential hosts (Can- gialosi, 1990a). Vollrath (1984) argued that Argyrodes can be placed in two general categories; specialists that are host specific but behaviourally versatile, and generalists that invade the webs of many different species but use relatively few techniques to ob- tain food. Thus, Whitehouse (1988a) considers Argyrodes antipodianus a specialist, primarily because its behaviour is versatile, and adults are found primarily on the webs of Eriophora pus- tulosa. Dichotomies like these can be misleading because both host-specificity and behavioural versatility are most likely continuous rather than discrete variables; A. antipodianus is found on the webs of several other hosts (Table 1). Further- more, host-specificity may also vary between populations, depending on the diversity and abundance of potential hosts in different popula- tions. For example, A. antipodianus in Whitehouse’s (1988a) study may be found primarily on Eriophora pustulosa because that is the most common host in her New Zealand population. The host range of Argyrodes may vary accord- ing to whether the species is both kleptoparasitic and predatory or whether it is only klep- toparasitic. Purely kleptoparasitic Argyrodes may escape host-detection through specialised behaviours, but these behaviours may be effec- tive for relatively few host species. If so, the host ranges of primarily kleptoparasitic Argyrodes may be less than for species of Argyrodes that are also predatory. The comparative data provide little support for this prediction (Table 4); al- INTER-SPECIFIC ASSOCIATIONS though the hosi-range of primarily klep- loparasilic species is less than the range of predatory species, the difference is not statistical- ly significant. ‘The results of these inter-specific comparative analyses within the genus Argyrodes should be interpreted cautiously. These patterns may be confounded by an association between foraging Strategy and taxonomic affinity, and thus the dif- ferences in body size or host range may be due to olher, unknown features that differ between these two groups. This possibility is especially relevant given the ambiguity of the taxonomic arrange- ment of this genus. Furthermore, some species of Argyrodes may be incorrectly assigned to primarily kleptoparasite status simply through lack of observations. Thus, the patterns may change when more data and/or a more accurate phylogeny become available. Nevertheless, the patterns suggest several interesting questions that could be resolved by an experimental approach. Host Specincrry OF KLEPTOPARASITES Both Argyrades and Mysmenopsis belong to web-building families and thus are relatively close phylogenetically (Coddington and Levi, 1991). However, the range and taxonomic af- finities of their hosts are substantially different (Table 1). Argyrodes have been recorded on the webs of 29 host genera from eight families (Agelenidae, Amaurobtidae, Araneidae, Linyphiidae, Pholcidae, Psechridae, Theridiidae, Uloborndae), and some species have many hosts (see above). In contrast, 1! of the 14 species of Mysmenopsis are found on diplurid hosts, with the remaining species found on Cyrtephora {Araneidae) and Pholcus (Pholcidae). A com- parative analysis reveals a significant difference: every species of Mysmenopsis has only one host species, while the host range for Argyredes is 2.7 (+0.7, n=18) species, or 1.6 (+0.3) host families. Why is Mysmenopsis more host-specific than Argyrodes? There are several possible explana- tions. First, Kleptoparasitism may have evolved more recently in Mysmenopsis than inArgyrodes, and therefore the former kleptoparasite has had less time to expand its host range. Second, the present associations between Mysmenopsis and diplurids may have evolved from a common an- eestor and subsequently speciated as host/klep- toparasite pairs. Consistent with this is Coyle and Mcigs (1989) description of two sister species of kleptoparasites (Mysmenopsis monticala and M. Jfurtiva) that live on the webs of a pair of un- 419 described allopatric Ischnothele morphs that also appear to be sister species. Third, diplurids may be more sensitive to web invaders than the hosts of Argyredes, and thus the Kleptoparasitic be- haviours required to avoid detection by one host Species are not appropriate for another, In this regard, it is noteworthy that Arevrodes are not known to invade diplund webs, despite the bronx! taxonomic range of their hosts. The relatively permanent nature of the host's wed is a common characteristic of the hosts of all kleptoparasites (Table 1). Kleptoparasites that live on permanent webs may benefit by spending less time searching for new webs compared with those that are associated with hosts that frequent- ly move their webs. However, it may not be the permanent stnictare of the web that is important. but rather the tenacity of the web site. Por ex- ample, the large, nocturnal, Australian orb- weaver Eriophora transmarina builds anew web every evening and then destroys it the following dawn. Despite the temporary nature of its web, this. spider is also host to many individual Ar- gyrodes, probably because it has a high web-site tenacity (M. Herberstein, unpublished data). MIMICRY BY SPIDERS Many species of animals, including spiders, resemble other, unrelated species, These resemblances may be visual, chemical, be- havioural or acoustic and are usually referred to as mimicry. There are many different types of mimicry, which has precipitated some controver- sy over its definition (e.g. Endler, 1981: Pasteur, 1982). Two general forms of mimicry are distin- guished in this review: defensive mimicry and aggressive mimicry. In the former, the minvetic form is presumed to have evolved because the risk of predation (or parasitism) on the mimic is reduced as a result of its resemblance to the model. The lower mortality occurs because the receiver (the predator) does not usually prey on the model, and fails to distinguish between it and the mimic. Aggressive mimics resemble some feature of their prey species, thereby increasing the chance of capturing the prey model. Both forms of mimicry occur in several families of spiders, The relationship between mimic, model and receiver is asymmetnoc; only the mimic benefits and any improvement in the mimic will be favoured rapidly by natural selection. Both the model and the receiver may lose, in defensive mimicry, through increased attack rate and lost 420 MEMOIRS OF THE QUEENSLAND MUSEUM Source Po Fam | Sari [Species \Castianeiradubium ——_| Pachycondyla obscurtcornis | Reiskind (1977) Oliveira (1988) Pachycondylaunidentaia | Oliveira (1988) [Myrmecium velutinum __|Co Myrmecotypus cubanns Formicinae Myrmecotypus fuliginasus Jackson & Drummond (1974) Reiskind (1977) Ponerinae Micaria pulicaria Gn Micaria sp. Gn Micaria scintillans Formica fusca Bristowe (1941) Phrurolithus festivus Lio _| Formicinae Phrirolithus minimus Formicinae Martella furva Scat Martella furva Formicinae [Myrmicinge | Acundhiomyrmex niger __| Bristowe (1958) Reiskind (1970) Oliveira (1938) Camponatus planatus Myers and Salt (1926) Paclrycandyla villosa Oftveira (1988) Hingston (1927) Lasius niger Brnstowe (1941) Farmica fausea Bristowe (1941) [Sa [Formicinae _|[Campanowus brevis __| Reiskind (1977) Reiskind (1977) ONLY Myrmarachie elongata [sa | Pseudomynmecinae Edmunds (1978) Myrmurachne foenisex lsa_| Formicinae Oecophylla langineda Edmunds (1978) Myrmarachneformicaria _|Sa Formica rufa Bristowe (1941) = 3 & 8. Sa__| Formicinae Mynnarachne parallela im Myrmaraclue platuleoides Mynmarachine sp. arinda tinda . B) By velex occidenjalis = |c win jae eS |e |e Synayeles ovcidenteles — Sigl= = = = < < & & 3 : S 5 2 else S = 7 % ww we ws e Synemesyna sp, a ia Nemosyha americana | S 2 & E utler (1991) Cutler (1991) geles venator Engelhardt (1970) Reiskind (1977) Psendomyrmecinae | Preudontyrmes boopis Reiskind (1977) Synemosyna aurantiaca Sa Oliveira (1988) Synemoxyna smithi [Sa__|[Pscudomyrmecinae | Pseudomyrmaclongara —_| Myers and Salt (1926) memosyna smith Zuniga laeta Oliveira (1988) Zuniga magna Pachycondyla villosa Oliveira (1988) Anaten formearia [ta [Myrmicinae | Chelanercrocceiventre —_| Reiskind and Levi (1967) Hingston (1927) iegon___|Sa__[Formicinae | Camponatsacrapimensis_| Fsimunds (1978 Polyrhachis Jackson (1986) Reiskind (1977) yrmarachine parallela 8 [Ponerinae _| Puchyeondylastriarinodis _| Reiskind (1977) Sa Oecophyila smaragdina Hingston (1927) 5 Hingston (1927) Mathew (1954) tne ackson & Drummond (1974) | Pheidole indica Hingston (1927) Myers and Salt (1926) TABLE 5 (part). Taxonomic distribution of spiders that mimic ants, including those that also prey on the model. spiders observed with dead ants.Family abbreviations given in Table 1, food respectively (see Endler, 1991), and natural selection will favour models that have less resemblance to the mimic (although the strength of this selection will depend on the frequency with which the model is attacked). The degree of resemblance between model and mimic that evol- ves will depend upon the benefits to the mimic and the costs of mimicry to the model. The costs is the same individual. INTER-SPECIFIC ASSOCIATIONS Castianerra sp. 1Cl [Formicinne 7 Cosnioplasix sp. 1 t Cosmoplasis sp. 2 Myrmarachne sp. Ee nee Tre finer similis Formicinae PREDATOR Formicinae Anyejaed forticeps Tm __| Formicinae Bucranium a icinae Aphanochilus foyersi Zodarion Table 5. continued Visuar Mimicry: Spiwers or ANTS Spiders that resemble ants are an especially intnguing form of mimicry that is poorly under- stood. Many of these spiders not only have an extraordinary physical resemblence with their ant models, but also exhibit particular behaviours that improves the illusion remarkably, Ant- mimics, represented in at least six families of spiders and mimicking the four major subfamilies of ants (Table 5), fall into two categories: those that appear to have little behavioural interaction with the ants and generally avoid contact with them; and those spiders that specialise on captur- ing and eating their ant models, There are no clear taxonomic affiliations between the species of spider mimics and the species of ant models: ponerine, myrmecine and formicine ants are models for both clubionid, salticid and other spiders. Nevertheless. certain species of ants ap- pear to be models for spiders more frequently than others. For example, seven species of Cam- ponotus are models to spider mimics and one species, C. fernoratus, is a model for two corin- nids (Myrmecium) and the salticid Zuniga; five species of the ponerine genus Pachycondyla are models for five different spiders, and the weaver ant Oecophylla smaragdina is a model for three species from Australia and India, It is notobvious why spiders mimic these genera of ants more frequently than others. Some species of spiders mimic more than one species of ant. For example, the clubionid Cas- ifaneira rica resembles species of both ponerine ind myrmicine ants and the different mimetic forms depend upon developmental changes, colour variation in adult females, and sexual dimorphism (Reiskind, 1970). Male C. rica resemble Atta and Odontomachus, while females An} Taxs | Fam an cles Camponotus paria Iss [Formicinae | Camponotus fulvoptlosus Cunis (1988) Hingston (1927) Qecophylla smaragdina | Cooper et al. (1990) Hubronestex bradleyi jae eis —_J Dolichoderinae R. Allan (pers. comm.) Partie — Tage aches Hingston (1927) A2i Hingston (1927) Campononss detritis [Cunis Li988) Camponotus Wing (1983 Oecophylla smarapdina Cooper et al. (1990) Decaphyila smaragdine Hingston (1927): Mathew (1954) Cephatotes (= Cryptocerus) Bristowe (1941) Oliveira and Sazima (1984) resemble moderately large ponerines that are within the spiders’ colour range. Furthermore, different instars of these spiders mimic ant models of equivalent size: thus the small, black early instars mimic small myrmicine ants, while the older instars resemble medium sized attine ants. Such a close degree of resemblance at dif- ferent stages in the spiders’ development sug- gests that the selection pressure fayouring mimicry is very strong. Ant mimicry can provide at least three benefits, depending upon whether the spiders prey on their ant models. These benefits include protection from various predators, improved predatory suc- cess on the ant prey, and both, Ant-mimics that apparently do not prey on their models are mostly salticids, corinnids and a few gnaphosids (Table 5). Mimics that prey on their models are mostly represented by thamisids and zodarids, although there are also a few records of theridiids, corin- nids and salticids (Table 5), The record for the salticid species Myrmarachne (Hingston, 1927) is unusual and unlikely to be typical because other species of this large. ant-mimicking genus do not routinely prey on their model ants (e.g. Edmunds, 1978). Only a few genera of salticids are clearly regular ant-predators (e.g. Jackson and van Ol- phen, 1991. 1992). The theridiid Dipoena resembles the de-capitated head of a dead ant which are found in the refuse heap of the ant nest, Hingston (1927) suggests that mimicry in this species is aggressive because it allows the spider to live in the nestof the ants on whom it may prey. However, predation on these ant hosts by Dipoena was not observed. Perhaps the most vexing question concerning defensive ant mimicry by spiders is establishing the identity of the receiver (i.e. the predator or > 22 MEMOIRS OF THE QUEENSLAND MUSEUM [Spider Ant = [Family [Subfamily [Species Bourct ‘Gene tengges _pe__vspenfsh Robinson & Robinson (1971) Chrysilla lauta Sa____|notspecified | Jackson & van Olphen (1992) | Corythalia canosa Sa not specified Habrocestum pulex Sa Formicinae ., Prenolepis sp. Cutler (1980) Ponera pennsylvanica Cutler (1980) not specified Siler semiglaucus Sa not specified Natta sp. Sa Jackson & van Olphen (1992) Natta rufopicta Sa Jackson & van Olphen (1992) Sa Pystira orbiculata Jackson & van Olphen (1991) Jackson & van Olphen (1992) not specified Corythalia canosa Edwards et al. (1975) Euryopis californica Td Formicinae Camponotus Porter & Eastmond (1982) Euryopis coki Td Myrmicinae Pogonomyrmex Porter & Eastmond (1982) Euryopis funebris Td Formicinae Camponotus castaneus Carico (1978) Latrodectus hesperus Td Myrmicinae Pogonomyrmex rugosus MacKay (1982) Latrodectus pallidus Td Mynmicinae Monomorium semirufus MacKay (1982) Steatoda fulva Td Myrmicinae Pogonomyrmex badius Hdlldobler (1971) Achaearanea sp. Td Formicinae Oecophylla smaragdina Cullen (1991) Saccodomus formivorous Dolichoderinae | /ridomyrmex McKeown (1952) Strophius nigricans Formicinae Camponotus crassus Oliveira & Sazima (1985) Zodarion frenatum Formicinae Cataglyphis bicolor Harkness (1976) TABLE 6: Spiders that specialise on ant prey but are not ant-mimics.Family abbreviations given with Table 1, parasitoid). Despite widespread reports and descriptions of ant-mimicry by spiders, few studies have addressed this question quantitative- ly. The visual nature of ant-mimicry suggests that the spiders are gaining protection from visual enemies, including birds (e.g. Belt, 1874; Engel- hardt, 1970), wasps (e.g. Edmunds, 1993) and other spiders (e.g. Cutler, 1991). Itis unlikely that the visual resemblance to ants provides the spider mimics with protection from either their ant models or other species of ants, because ants perceive the environment primarily by chemical, rather than visual cues (see Hélldobler and Wil- son, 1990). Furthermore, many spiders that are either specialist predators of ants (see Table 6) or live in close proximity with ants (Table 7) are not necessarily visual mimics. Most of the diet of many spiders are other spiders (e.g. Bristowe, 1941, 1958; Reichert and Luczak, 1982; Nentwig, 1987). In contrast, ants are not a common prey item for most spiders, although a few spiders are specialist predators of ants (see Table 6). Thus, ant mimicry may pro- vide some degree of protection from other spiders. Experimental evidence of this possibility is provided by Cutler (1991), who examined whether ant-mimicry in the salticid Synageles occidentalis, a mimic of the ant Myrmica americana, reduces the risk of predation by two other spiders Tibellus (Philodromidae) and Phidippus (Salticidae). These spiders do not feed on the ant M. americana, but more importantly they were less likely to attempt to capture the mimic S. occidentalis than immature Phidippus (that are not ant mimics). Spiders are also prey to a variety of other inver- tebrates, especially pompilid and sphecid wasps (e.g. Coville, 1987), and acrocerid dipterans (e.g. Schlinger, 1987). These parasitoids are primarily visual hunters and many myrmecophilous arthropods gain protection against these enemies by associating with ants (e.g. H6lldobler and Wil- son, 1990). Thus, ant-mimicry may reduce the risk of predation by sphecid and pompilid wasps. Edmunds (1993) provides qualitative data sug- gesting that ant-mimics Myrmarachne are less likely to be taken by the predatory wasp Pison xanthopus than might be expected if this wasp was indiscriminate in its choice of prey. Finally, it is interesting to note that no species of lycosid have been reported as ant-mimics (see Table 5), perhaps because these spiders are generally noc- turnal foragers and are also seldom victim to sphecid wasps (see Coville, 1987). BEHAVIOURAL MIMICRY: COURTSHIP VIBRATIONS Some spiders are renowned for preying ex- clusively on other spiders. Notable among these INTER-SPECIFIC ASSOCIATIONS $23 —— 4g Tetrilusarientnus Formicinae Camponotus inci Noonan (1982) [Acartaucheniusscurritis {Lin _| Formicinae __|Teeramoriumeaespitum (| Briawe(1958) | Cochlembulus formicarius eal Formica obscuripes Evansia merens [tin | Formicinae | Formica i Formicinae Pogonomyrmex Porter (1985) vreasthenins biovatus Lin Formicinae Formica rufa PRrurolithus ——— aoe ——— uster [Pro ___|not specified _| Isa Dolichodenmae_| Tapinoma melanocep as, Shepard & Gibson (1972) TABLE 7: Spiders that have been found within or adjacent to the nests of ants, Family abbreviations given with Table 1. are the mimetid or pirate spiders that invade the webs and attack the owners of other species of spiders (e.g. Bristowe, 1941). Many of these spiders are aggressive mimics. For example, the mimetid pirate spiders Mimetus and Ero wait at the periphery of the web of the social spider Anelosimus studiosus (Brach. 1977). The mimetids then pluck on the web thereby attract- ing 4 host spider that 1s then captured and eaten. The salticid Portia is also well known for its ability to mimic the struggles of prey ensnared in the web of other spiders. The investigating host is then captured by Portia (Jackson and Hallas, 1990). Some species of Portia also mimic the male courtship behaviour of their prey species; a be- haviour that increases their chances of capturing the unsuspecting female (Jackson and Hallas, 1986). If prey populations suffer high frequencies of this form of mimiery, then Portia may act as a selection pressure favouring improved dis- criminatory abilities in the prey, thereby estab- lishing an an evolutionanly dynamic ‘arms race’ (sensu Dawkins and Krebs, 1979), Evidence of this form of frequency dependent selection is provided by Jackson and Wilcox (1990, 1993), in their study of the predatory-prey relationship be- tween two Australian salticids, Portia fimbriata and Euryattus sp. Euryattus females live in a nest comprising a rolled-up leaf, suspended from rock ledges and tree trunks by silk guylines. Portia fimbriata is a versatile predator of many salticids and in a Queensland population, it preys on female Euryallus sp. using vibratory displays that ap- parently mimic the courtship behaviour of Eurvattus males.This behaviour lures Evryartus females From their nest. and they are sub- sequently attacked by P. fimbriata. This specialised form of predation by P. fimbriata may be responsible for the improved ability of Euryat- tus to recognise and defend itself from I’. Jimbriata, compared with other salticids. For ¢x- ample, Eurvanus recognises P. fimbriata as a potential predator, unlike another prey species Jacksonoides queenslandica. Interestingly, this recognition ability is not present in another population of Euryatius in which P. finibriata are absent. Experimental trials reveal that P. fimbriata attacks and captures these ‘naive’ spiders more frequently than spiders from the population that is exposed to P. fimbriata (Jack- son and Wilcox, 1993). Iris still not clear whether the two populations of Euryattus are conspecifics or represent two different species. The more dis- tantly related the two populations, the less likely that the differences in behaviour are the result of the presence or absence of P. fimbriata. Never- theless. it appears to be a fascinating example of how the foraging behaviour of a predator has apparently acted as a selection pressure influenc- ing the defensive behaviour of its prey- CremicaL Mimicry: Mots AND ANTS Spiders produce a variety of chemicals that function to attract conspecifics. Female spiders from many different familtes produce pheromones that attract members of the opposite sex (e.g. Lopez, 1987; Pollard ef a/., 1987), and Evans and Main (1993) show experimentally that pheromones may be important for maintaining social cohesion in social spiders. Several taxa of spiders are capable of inter-specific chemical communication, of which the most familiar is the remarkable form of chemical mimicry by bolas spiders (see Stowe, 1986, 1988 for extensive reviews). Bolas spiders, comprising several genera within the Araneidae, do not construct 424 orb-Webs but instead swing at their prey a bolas (a droplet of adhesive) attached to the end of a silk thread. Bolas spiders are aggresstve mimics and prey exclusively on male moths; the spiders produce a chemical substance that mimics the sex pheromone of its moth prey species (see Eber- hard, 1977, 1980; Yeargan, 1988: Stowe, 1986, 1988; Stowe er ai., 1987). The exact source of the prey altractant compounds is not known, bul 3s likely to be emitted from the spider (Stowe ef al, 1987). The evolution of this specialised foraging technique is particularly intriguing because it in- volves two phases; the first compnses the produc- tion of moth-attracting chemicals (see also Horton, 1979), and the second is the adoption of a specialised use of silk together with the loss of the orb-web. Interestingly, anecdotal observa- lions sugges! that the spider swings the bolas in Tesponse to vibratory signals generated by the flying moths (Main, 1976). The mate location mechanism of at least seven families of moths are exploited by bolas spiders, but the range of moth prey species captured by each species of bolas spider vanes (Stowe, 1986, 1988; Stowe ef al., 1987), Some spiders capiure only one species of moth, while Mastophora cer- nigera is capable of capturing at least nineteen moth species (Stowe ef al.. 1987). There are no obvious taxonomic affinities between the di- ferent groups of bolas spider and their moth prey species (Stowe, 1986, 1988). The vanation in bolas spider prey-specificity is likely to be related to the bio-geographic distnbution of potential moth prey, the chemical compounds produced by the spiders and the chemicals used as moth sex- attractants, Furthermore, some compounds that attract certain species of moth may inhibit attrac- lion of other moths (Stowe et al., 1987). Since araneid spiders are capable of chemical mimicry of moths, it is nol unressonuble to expect that ant-mimicking spiders may be capable of preducing chemical compounds thal ‘appease’ ants. Many species of invertehrate myr- mecophiles produce chemicals that mimic ant communication chemicals (see Holhdobler and Wilson, 1990). The production of these chemi- cals can reduce the nsk of the ants attacking the myrmecophiles. One group of spiders thal are likely to be capable of chemical mimicry are those that live in ant nests (see Table 7). Little is known about these spiders, bul some earlier reports may have mistakenly recorded them living in ant nests, rather than adjacent to the nest (see Bristowe, 1941), Itas nol clear whether these Spiders prey on the ant larvae within the ant nest, MEMOIRS OF THE QUEENSLAND MUSEUM or simply take advantage of a safe reluge. Whatever the reason, ttis unlikely that they could remain in ornear ant nests without some chemical protection, because ants rarely tolerate foreign nest intruders. Porter (1985) provided qualitative evidence for the presence of ant recognition pheromones by introducing myrmecophilous spiders Masoncus into the nests of different ‘ogonomyrmes ants, Masoncus were not attack- ed if they were re-introduced into their original nests, but the spiders were attacked and killed within minutes if they were placed in the nest of foreign Pogonomtyrnex or other species of ants, It is not Known whether these spiders actively produce the appropriate pheromones, or whether they simply adopt it from the substrate of the nest. The predatory behaviour of two Australian spiders may also invelve chemical mimicry, The Australian basket-web spider Saccedamus for- inivorous (Thomisidae) builds a basket-like web that appears to attract wandering Iridomyrmex ants that may venture into the basket web (Mc- Keown, 1952). The spider also taps the ant with its legs, that may further mimic ant communica- tion, and eventually captures the unsuspecting ant Itremuins to be scen if 8. formiverous webs capture only /ride@myentex ants, and whether the ants are actively attracted to the basket-web, The extraordinary predatory relationship between an undescribed theridiid and its weaver ant Oecophyila smaragdina prey (see Cooper et al., 1990) may also represent an example of the use of chemical mimicry. This theridiid constructs a web made of several strands of silk suspended between vegetation and additional strands that are anchored to the substrate below. The anchor part is a small white bead of silk that is very attractive to the ants, If the web is complete and an ant bites the silk it is catapulted into the web above, where it is captured by the spider. The bead of silk is often placed near ant ‘highways’ and can sometimes attract the attention of many individual O. smaragdina that all attempt to bite the silk. MUTUALISTIC ASSOCIATIONS There are few examples of mutualistic associu- tions between species of spiders or even between spiders and other organisms, This is surprising, given the widespread occurrence of mutualistic associations in other taxa (e.g. Boucher er at., 1982; Smith and Douglas, 1987; Hélidohler and Wilson, 1990). but may reflect the predatory na- ture of spiders. Tietjen ef al. (1987) desenbe an INTER-SPECIFIC ASSOCIATIONS interesting example of a mutualistic association involying the social spiders Mallos gregalis. These spiders do not remove the remains of prey from their nest, and this debris becomes a nutrient base for various yeasts. The odour of these yeasts 18 apparently attractive to various flies, that settle on the prey carcasses and are then captured by the spiders. The association is likely to be mutualistic because the spiders provide food for the yeast and the yeast’s presence attracts food for the spider. The relationship between spiders that live in unis’ nests and their ant hosts may also be mutualistic for some species. For example, Shepard and Gibson (1972) found myr- mecophilous salticid spiders of the genus Cotimesa in 61% of 50 nests of the dolichoderine ant Tapinoma melanocephalum. Interestingly, ant nests with Cotinusa had more breed per nest, more workers per nestand more brood per worker than those nests without Cotinusa. Unfortunately, these differences were not examined statistically. and the greaier numbers of ants and brood in the nests with Cotinusa may be due to the larger size of the farmer nests. Nevertheless, Shepard and Gibson (1972) suggest that the spider uses the ant nest as a foundation for the construction of its web, and in return provides the ants with seme protection from predators or parasites. PSECHRUS AND PHILOPONELLA Many species of orb-weaving spiders in the genus Philoponella(Uloboridac) build their webs within the barrier webs of other araneid, theridiid, agelenid and psechrid spiders (Struhsaker, 1969; Lubin, 1986). These associations were thought to be commensal; Philoponella bas a place to build a web, but it was assumed that their presence has little effect on the host spider (e.g. Lubin, 1986), In Madang Province, Papua New Guinea a species of Philoponelia builds webs between the threads of the tangle web of a large psechrid Psechrus argentatus. Not all Psechrus webs have Philoponella, but as many as 15 males and females can be found on a single host web. Like many small uloborids. Philoponella is a com- munal spider, with several orb-webs sharing sup- port threads. A theridiid Argyrodes fissifrons also patrols the barrier web but is never found on the sheet web of the host spider. The number of both A. fissifrons and Philoponella on a single host web is positively correlated with the size of the host. The relationship between P. argentatuy and Philopenella appears to be mutualistic (Elgar, unpublished). The growth rate of P. argeniatus az was significantly reduced following experimen- tal removal of both A_fissifrons and Philoponelia from the barrier-web. The lower growth rate during the ten day experimental period may rep- resent a potential reproductive loss of around 30 eggs (estimated from the weights of egg masses). P. argentatus probably benefits by increased cap- ture rates as aresult of ihe increased area of tangle web generated by the webs of Philoponelia, in a way analogous to the webs of some social spiders (see Struhsaker, 1969; Uetz, 1958). The addition- al webs may increase the probability of arresting insects that then drop into the sheet web, without being caught in the orh-web of Philoponelia. It seems unlikely that P. argentatus benefits from the presence of A. fissifrons. In fact, A. fissifrons is move likely to have a negalive effect on the hast because it feeds on prey items caught in the barner web and also may prey on Philoponella: on two occasions, A, fissifrous were seen feeding on Philoponella, consistent with other reports of the foraging behaviour of this species (see Tabic 1). SOME CONCLUSIONS AND PROSPECTS The relationship between kleptoparasitic Ar- eyrodes and their hosts has been extensively ex- amined, yet the effects of the association on the fitness components of either Argyrodes or its host are presently unquantified. Consequently, it may be inappropriate to call these species klep- toparasites because (a) they may not take prey that the host would otherwise feed on and (b) their hosts may not suffer a fitness cost. Of course. many other well documented host-parasite sys- tems similarly fail to quantify the fitness effects of the presumed parasife (see Toff et af., 1991). Nevertheless, circumstantial evidence that the presence of Argyrodes has influenced the hinlogy of at least a few host species suggests that klep- poe werden is an evolutionarily dynamic relationship. Comparative analyses reveal inter- esting differences in the biology of klep- toparasites that do, or do not, also prey on their host. However, there are no obvious explanations for the evolution of this behaviour, There are interesting parallels hetween chemi- cal mimicry by the bolas spider and yibratory mimicry by the salticid Portia, both are examples of aggressive mimicry in which the mimic ex- ploits the mate-attracting mechanism of the modeL They alse illustrate the broad spectrum of sensory mechanisms that are exploited and the range of phylogenetic similarity between modcl 426 and mimic. The models are clearly disadvantaged by the mimics, and selection is likely to favour mechanisms that allow the victims to distingutsh between their conspecific mates and the spider predators. There is some evidence of this selec- tion for Euryettus, the model of Portia, but there are no data on the impact of bolas spiders on their model moth populations (but see Yeargan. 1988}, nor ts it known whether the ability of male moths to discriminate between conspecific female pheromones and bolas spider mimics has changed. One difference between these two mumicry systems ts that the victims of Portia are female, but the victims of bolas spiders are male. This difference may have implications for the relative strength of selection in these types of aggressive mimicry, and the degree to which the model and mimic have undergone an evolution- ary arms race. Defensive mimicry of ants by spiders is taxonomically widespread but has received little experimental attention, compared with studies of other invertebrate taxa (e.g. McIver, 1987), In almost all cases the receiver is not identified and the fitness cost to the ants, as a result of defensive mimicry by these spiders. has not been quantified. Nevertheless, the degree of visual mimicry in many spiders suggests that there has been strong selection for this form of protection against predators. The inter-specific variation in the de- gree of resemblance between spider mimics and their ant models suggests an evolutionary process reflecting differences in the discriminatory abilities of the receivers. These differences may alse reflect the frequency with which the spiders and ants co-oecur, and the kind of substrate on which both are found. Finally, ant mimicry by spiders that also prey on their models begs the question of whether specialisation on ant prey followed ant mimicry, or vice-versa. Mutualisms inyolving spiders have received little attention, compared with other inter- specific associations. There are several explana- tions: the Araneae may be characterised by an absence of mutualisms; these mutualisms simply have pot been detected; or non-mutualistic as- sociations may even have been incorrectly in- terred. For example, the impetus of my study of Psechrus, Philopenelia and Argyrodes was to reveal the fimess costs to the host of what ap- peared to be a kleptoparasitic relationship. The correct nature of the relationship between the species was only revealed experimentally, and this is likely to be true of many other inter- specific associations described im this review. 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Turelina similis (Araneae: Salticidae); an ant mimic that feeds on ants. Journal of the Kansas Entomological Society 56: 55-58. WISE, D.H. 1982. Predation by a commensal spider. Argyrodes frigonum, upon its host; an experimen- tal study. Journal of Arachnology 10: 111-116. YEARGAN, K.Y. 1988. Ecology of a bolas spider, Mastophora hutchinsoni: phenology, hunting tac- tics, and evidence for aggressive chemical mimicry, Oecologia 74: 524-530, VERTICAL DISTRIBUTION AND ABUNDANCE OF PSEUDOSCORPIONS (ARACHNIDA) IN THE SOIL OF TWO DIFFERENT NEOTROPICAL PRIMARY FORESTS DURING THE DRY AND RAINY SEASONS JOACHIM ADIS AND VOLKER MAHNERT Adis, J. and Mahnert, V. 1993 11 11: Vertical distribution and abundance of pseudoscorpions (Arachnida) in the soil of two different neotropical primary forests during the dry and rainy seasons. Memoirs of the Queensland Museum 33(2): 431-440. Brisbane. ISSN 0079-8835. Pseudoscorpions were extracted from 0-14cm soil depth in two dryland (upland) forests near Manaus, Brazil. In a primary forest on yellow latosol, about 1700 specimens per m* were obtained during the dry season and 1135 during the rainy season. They accounted for 10-15% of all arthropods extracted, excluding Acari and ColJembola. In a primary forest on white sand soil (campinarana), about 530 specimens per m” were obtained during the dry season and 480 during the rainy season. They accounted for only 3-4% of all arthropods extracted, again excluding Acari and Collembola. Significant but different correlations were found in both forest types between the abundance of pseudoscorpions and changing moisture, temperature and pH conditions in relation to soil depth and season. Neither during the dry season nor during the rainy season was the abundance of pseudoscorpions in mineral subsoils higher in response to the changing soil moisture content in organic layers. This was reported for arthropods from forests in the seasonal tropics where periods without precipitation occur, Results are discussed at the species level. They are compared with published data on the vertical distribution and abundance of pseudoscorpion species from the yellow latosol of a secondary dryland forest (dry season and rainy season) from the same region. In zwei Festlandwildern in der Umgebung von Manaus wurden Pseudoskorpione aus 0-14cm Bodentiefe extrahiert. In einem Primarwald auf gelbem Latosolboden wurden wahrend der Trockenzeit 1700 und wihrend der Regenzeit 1135 Individuen pro m~ nach- gewiesen. Sie reprasentierten 10-15% aller extrahierten Arthropoden, Acari und Collembola ausgenommen. In einem Primérwald auf WeiBsandboden (campinarana) wurden wiahrend der Trockenzeit 530 und wahrend der Regenzeit 480 Individuen pro m” nachgewiesen. Sie reprasentierten nur 3-4% aller extrahierten Arthropoden, Acari und Collembolen wiederum ausgenommen. Signifikante aber unterschiedliche Korrelationen ergaben sich in beiden Waldtypen zwischen der Abundanz der Pseudoskorpione und der sich andernden Feuchte, der Temperatur und dem pH in Bezug auf Bodentiefe und Jahreszeit. Weder wahrend der Trockenzeilt, noch wahrend der Regenzeit, war die Abundanz der Pseudoskorpione im mineralischen Unterboden als Folge auf die sich andernde Feuchte im organischen Ober- boden héher. Dies wurde fiir Arthropoden in Waldern der saisonalen Tropen, die Trocken- perioden durchlaufen, nachgewiesen, Die Ergebnisse werden auf Artniveau diskutiert. Sie werden mit publizierten Daten tiber die Vertikalverteilung und Abundanz von Pseudoskor- pionarten aus einem Sekundarwald auf gelbem Latosolboden im gleichen Gebiet verglichen. UPseudoscorpiones, abundance, seasonality, vertical distribution, Neotropics. Joachim Adis, Tropical Ecology Working Group, Max-Planck-Institute for Limnology, Postfach 165, D-2320 Ploen, Germany, in cooperation with National Institute for Amazonian Research (INPA), Manaus, AM, Brazil; Volker Mahnert, Muséum d'Histoire naturelle, Case Postale 434, CH-1211 Genéve 6, Switzerland; 23 November 1992. In those wet but markedly seasonal tropics where periods without precipitation occur, ter- restrial arthropods are reported to migrate to mineral subsoils in the dry season as a response to changing humidity in organic layers (Beck, 1964; Bullock, 1967; Goffinet, 1976; Lawrence, 1953; Levings and Windsor, 1984; Liebermann and Dock, 1982; Merino and Serafino, 1978; Petersen and Luxton, 1982; Rybalov, 1990; Strickland, 1947; Willis, 1976 and others). Central Amazonian dryland (= non-flooded upland) forests experience a rainy season (December-May; average monthly rainfall 211- 300mm) and a ‘dry’ (= drier) season (June November; average monthly rainfall 42- 162mm). Annual precipitation is 2105mm (based on 75 years of records from the meteorological station at Manaus, cf. Ribeiro and Adis, 1984). About 75% of the rainfall (1500mm) is recorded during the rainy season. This had no observable difference in vertical distribution of terrestrial arthropods in primary forests on yellow latosol 432 DRY SEASON Nim?: 7025 6351 259.8 1059 45 41%) 2 1,703.3 = N/m 035° 35-70 70-105 105-140 Soil Depth (cm) [["]-nymphs MEMOIRS OF THE QUEENSLAND MUSEUM RAINY SEASON N/ me : 4331 3321 2406 129.9 45 4(%) 5 = N/m =1,135.7 30 15 0-35 35-70 7.0-10.5 10.5-44.0 Soil Depth (cm) [__]=adults e—e=soil moisture content FIG, 1. Distribution of pseudoscorpions in soil and soil moisture content (both in %). Samples taken every 3.5cm to depth of 14cm in dry season and in rainy season in primary dryland forest on yellow latosol near Manaus, Brazil. Total catch each season = 100%. Abundance for each soil layer (N/m? ) and for total catch/ season (SN/m’). and on white sand soil (Adis ef al., 1989a, b, unpublished data; Morais, 1985). However, results were based mainly on data for orders. Evaluation of sampling data at the species level is now possible for pseudoscorpions, since iden- tification has been completed by the second author. STUDY AREAS PRIMARY ForREST ON YELLOW LATOSOL Sampling was carried out during the rainy (March) and dry seasons (October) of 1987 in a dryland terra firme forest at the Ducke Forest Reserve (= Reserva Florestal A. Ducke, 2°55’S, 59°59’ W) of the National Institute for Amazonian Research (INPA, Manaus), situated on the Manaus-Itacoatiara highway (AM-010; cf. Penny and Arias, 1982). The area sampled was classified as high terra firme forest (Takeuchi, 1961; cf. Brinkmann, 1971) with several species of large, broad-trunked trees (with or without buttresses). The trees reached 44m in height (average height: 22m) and formed a closed canopy. Approximately 235 species, representing 43 families of trees, were recorded in the study area. Most frequent were Leguminosae, Rosaceae, Lauraceae, Sapotaceae and Lecitidaceae. The forest had a patchy understorey and a scanty herb layer. Guillaumet (1987), Lech- thaler (1956), Prance (1990), Prance et al. (1976) and Rodrigues (1967) provide detailed botanical descriptions of the forest. Microclimatic data are given by Decico et al. (1977), Marques et al. (1981) and Ribeiro and Nova (1979). The soils near the Ducke Forest Reserve were described by Falesi and Silva (1969) as deep, yellow latosols, strongly weathered, excessively to very strongly acidic, of heavy texture in all profiles (A-C: 0- 110cm) and with clay content of the B horizon varying from 50-70%. In the study area, where entomological long-term investigations have pre- viously been undertaken (Adis and Schubart, 1984; Morais, 1985; Penny and Arias, 1982), the soil carried a 1-3cm thick humus layer (Ao), in- terspersed with fine roots and a thin leaf litter, covering most of the surface. For further details on the study area see Penny and Arias, 1982. During the 1987 rainy season, 322mm of rain were recorded in March (data from the meteorological station at Ducke Forest Reserve, provided by M. de N.G. Ribeiro at INPA, Manaus). On the day of sampling (March 20, 1987) soil moisture content (= weight difference between wet and dried soil samples in%) was 20.0% at 0-3.5cm (= humus layer), 17.5% at 3.5-7cem, 15.5% at 7-10.5cm and 17.7% at 10.5- 14cm soil depth, respectively (= mineral subsoil) (Fig. 1). Soil temperature at 10 a.m. decreased from 25.2°C in the top 3.5cm to 24.5°C at a soil NEOTROPICAL PSEUDOSCORPIONS 433 ORY SEASON % Nim@ {000 17033 === tridens2 =b6t==] 1,159.7 T minor 27 B brown) 5.8 gat |. schusteri 62 105.9 A. gracilis 3.7 624 P. hemadentatus ye 60{%) RAINY SEASON % 10u0 N/m 1,435.7 T minor 8 browni a2 Bl.A A gracilis 16 33.7 | schuslen $7 19.2 t_ tenuis 0.4 4.8 = ee 20 40 60 BO) FIG. 2, Dominance (%)and abundance (N/m*) of species of pseudoscorpions extracted from Im? of soil (Q-14cm depth) during dry season (October 1987) and rainy scason (March 1987) in primary dryland forest on yellow latosol near Manaus, Brazil. Total catch of each season = 1049. (See text for further explanation). depth of 14cm. The soil pH increased fromm 3.3 im the top 3.5cm to 3.8 in the Jower layers (3.5.- i4cm). During the 1987 dry season, 139mm of rain were recorded in October (data from the meteorological station at Ducke Forest Reserve), On the day of sampling (October 14, 1987) soil moisture content increased from 13.6% in the top 3.5em to 19.1% at a soil depth of 14cm (Fig. 1) and the soil pH increased from 3.3 to 3.8, Soil temperature at 11 a.m. varied slightly (24.6- 24.7°C) from the surface to 14cm. Primary Forest on Waite Sanp Sou. Sampling was carried out during the rainy season (March) and the dry season (Angust) of 1988 in a dryland campinarana forest of the Biological Reserve INPA/SUFRAMA (approx. 2°30'S, 60°10" W), at km 45 (formerly km 62) on the Manaus Boa Vista highway (BR -174), Cam- pinarana (= caatinga arbérea) was classified as a low, relatively light forest on white sand soil with thin-stemmed trees 10-20m high, with occasional large, broad-trunked individuals. with or without buttresses, a patchy understorey and no herb layer (Guillaumet, 1987; Anderson, 1981: Lisbda, 1975). Data on geomorphology and soil genesis ure found in Chauvel et al. (1987). Floral inven- tories have been given by LisbOa (1975). Braga (1979), Anderson er al. (1975), Anderson (1981) and Guillaumet (1987), while the mieroclimatic data were provided by Ribeiro and Santos (1975). In the study, area, the white sand soil carried a humus layer that was 10-Ilem thick (Ao), penetrated by a matting of roots and a thin, sur- face-covering leaf litter. During the 1988 rainy season, 293mm of rain were recorded in February and 280mm in March (data from the meteorological station of EMBRAPA/UEPAE, km 54). On the day of sam- pling (March 18, 1988) soil moisture content (= weight difference between wet and dried sui! samples in %) increased from 20.1% in the top 3,5cm to 26.2% at 10.5cm depth (= humus layer) and dropped to 9.9% at 10.5-14cm (= white sand soil) (Fig. 4). Soil temperature at 1) a.m. decreased from 24.7°C in the tap 3.Scm to 24.5°C at a soil depth of 14cm. The pH of the soil was 3.2 (0-3.5em), 3.3 (3,.5-7em), 3.6 (7-10,.5cm) and 3,7 (10.5-14cm), respectively. During the 198% dry season, 77mm of rainfall were recorded in August (data from the meteorological station of EMBRAPA/UEPAE, km 54). On the day of sam- pling (August O5, 1988) soil moisture content decreased from 21,9% in the top 3.S5cm to 9.5% at 10.Scm depth (= humus layer) and to 9.3% at 10.5-l4em (= white sand soil; Fig, 4). Soil temperature al 3 p.m. decreased from 27.1°C in the top 3.5em to 25,5°C at a soul depth of 14cm. The pH of the soil was 3.6 (0-3.5cm), 3.5 (3.5- 7em), 3.5 (7-10.Scm) and 3,6 (10,5-14cm), respectively. The relative light intensity on the forest floor was about 2.1% (210 Ix; comparative value-in the open airat3 p.m., 10.000 Ix (overcast sky); cf. Brinkmann, 1970, 1971). METHODOLOGY In both study areas, six soil samples were taken along a transect al random intervals with a split corer (a steel cylinder with lateral hinges; diameter 21em, length 33cm) which was driven into the soil with a mallet. Bach sample was taken toa depth of 14cm and was then divided into four subsamples of 3.5cm cach. Animals were ex- tracted from subsamples following a modified method of Kempson (Adis, 1987). All pseudo- scorpions Were separated by species [adults (males and females), nymphal mstars} and their 434 DRY SEASON RAINY SEASON 2 N/m”: 105.9 144 4.8 1p eobisium schusteri |= Nim? = 105.9 = Ninf = 192 50 Nim?; 1347 16.4 770 4.8 100 Brazilatemnus br owni ® 2 2_ Dn = N/m= 149.1 = N/m* =8 1.8 io) _— Cc a 50 oO [= i) ao T, ir 1, 1) Nim"; 48.1144 4.8 241 4.8 100 Albiorix gracilis = Nim = 625 = Nim?= 33.7 50 a -35 -7.0-105 -14.0 -3.5-70 -105 14.0 Soil Depth (cm) MEMOIRS OF THE QUEENSLAND MUSEUM DRY SEASON RAINY SEASON Nim?: 100 168.4385 48 107 28.9 Tyrannochthonius minor = N/m?=2117 : = N/m =139.6 50 ea | N/m2:2310 567825501059 -2262264.7235.8129.9 1004 Microblothrus tridens 2 a = Nim@= 1,159.7 2 = N/m*= 856.6 -3.5-7.0 -105-140 -3.5 -7.0 -10.5 44.0 Soil Depth (cm) =nymphs’ [__] = adults FIG. 3. Vertical distribution of five species of pseudoscorpions in soil (7). Samples taken every 3.5cm to depth of 14cm during dry season and rainy season in primary dryland forest on yellow latosol near Manaus, Brazil. Total catch each season = 100%. Abundance for each layer (N/m2 ) and total catch per season (% N/m‘). abundance was calculated for 1 m7. Vertical dis- tribution of adults and nymphs in relation to changing conditions of soil moisture content, temperature and pH was statistically evaluated with the linear correlation test (Cavalli-Sforza, 1972), using the original field data. RESULTS PRIMARY ForREST ON YELLOW LATOSOL Pseudoscorpions accounted for 10-15% of all arthropods extracted from 1m’ soil of 14cm depth (10,000-12,000 ind./m?, Acari and Collembola disregarded) in the study area (Adis et al., un- published data). During the dry season, about 41% of all 1,700 (+71) pseudoscorpions were collected from the top 3.5.cm, 37% from below the humus layer (3.5-7cm) and 22% at 7-14cm depth. About 54% of all specimens collected represented juvenile stages (Fig. 1: nymphs). Decreasing abundance of pseudoscorpions at greater soil depths was significantly correlated with increasing soil moisture content (adults and nymphs: P<0.01, r = -0.998, nymphs only: P<0.05, r = -0.956; n = 4). During the rainy season, vertical distribution was similar (Fig. 1): NEOTROPICAL PSEUDOSCORPIONS DRY SEASON 95 Nim@:| 2550 1443 624 721 60 = Nim? = 533.8 Percentage 0-85 45-70 70-105 105-140 Soil Depth (cm) =nymphs [__]= adults #©—e = soil moisture content 435 RAINY SEASON 75 Nim: 530 337 433 60 = Nim = 481.2 45 0-35 35-70 70-105 105-140 Soil Depth (cm) FIG. 4. Distribution of pseudoscorpions in soil and soil moisture content (both in %), Samples taken every 3.Scm to depth of 14cm during dry season and rainy season in primary dryland forest on white sand soil near Manaus, Brazil. Total catch cach season = 100%. Abundance for each soil layer (N/m?) and total catch / season (=N/m* ). 38% of the 1,100 (+46) pseudoscorpions were recovered from the top 3.5 em, 29% from 3.5- Jem and 33% from 7-l4cm soil depth. About 61% of the total catch were nymphs. Decreasing abundance of pseudoscorpions at greater soil depths was significantly correlated with decreas- ing soil temperature (adults and nymphs: P<0.01, r= +0.993, nymphs only: P<0.05, =+0.956; n= 4). Six species of pseudoscorpions were collected in both seasons (Fig, 2). All were previously reported from soils of Amazonian dryland forests (Mahnert and Adis, 1985), Syarinidae were most abundant, with Microblothrus tridens Mahnert (dry season: 116055 ind/m*, rainy season: 860 +24 ind./m?), Jdeobisium se husteri Mahnert and /deoblothrus tenuis Mahnert accounting for 74-78% of the total catch (Fig. 2), Chthoniidae was the next most abundant family, with Tyran- nochthonius (T.) minor Mahnert (= Lagynoch- thonius minor (Mahnert)): dry season; 2) 2+17.4 ind./m’, rainy season: 140+ 14 ind./m?) and (dry season only) Pseudochthonius homodentatus Chamberlin representing 12-13% of the total catch, Less abundant (>10%) were Miratemnidae (Brazilatemnus brownt Muchmore ; dry season; 149+ 20 ind./m’, rainy season: 82+ 13 ind. /m*) and Ideoroncidae (Albiorix gracilis Mahnert), Few differences in dominance were found for species captured during both seasons, however their abundance varied (Fig. 2). Except for A. gracilis, vertical distribution of pseudoscorpions in the soil differed between species but not within species when comparing different seasons (Fig, 3). J, schusteri and B. browni were only found at 0-7cm soil depth, with abundances being greatest in the top 3.5cm. This is also true for 7) minor which lived, like A. gracilis, to a soil depth of 10.Scm. However, occurrence was restricted to the upper 7cm in 7, minor during the ramy season and in A, gracilis during the dry season (Fig. 3). /. fenuis was found only at a soil depth of 3.5-7em (= below the humus layer) during both seasons, whereas M. tridens occurred in all soil layers (0-14cm). During the dry season, significant correlation was observed between decreasing abundance of 7. minor and greater soil depths (Fig. 3) and the ) At this locality, B. browni is apparently smaller. It may haye adapted lo its environment, thus representing an eCO-Species. 436 MEMOIRS OF THE QUEENSLAND MUSEUM DRY SEASON % — Nim@ RAINY SEASON % Nim@ 100.0 533.8 400.0 484.2 ET minor ieee] 43.3 230,9 ESS brown SS] 350 168.4 eS =M. tridlens 30.6 163.6 T. minor HHH] 32.0 154.4 B.browni W 914.3 28,0 134.8 |. schuster} 5.4 28.8 |. schusteri 3,0 14.4 ; P homodentatus 1.8 9.6 iu] A. arboricola 1.0 4.8 A A. arboricola 09 4,8 i T. rotundimanus 1,0 4.8 q] P crassifemoratus 0.9 4.8 y T T T = al 20 40 60 (%) 20 40 60 (%) FIG. 5. Dominance (%) and abundance (N/m*) of species of pseudo scorpions extracted from 1m? soil (0-14cm depth) during dry (August 1988) and rainy (March 1988) seasons in primary dryland forest on white sand soil near Manaus, Brazil, Total catch of each season = 100%. (See text for further explanation). increased soil moisture content (P<0.05; adults and nymphs: r = -0.959, adults only: r = -0.968; P< 0.10; r=-0.936 for nymphs only; n=4, respec- tively). Similar results were recorded from A. gracilis (P<0.05; adults and nymphs: r = -0.969, nymphs only: r=+0.974; n=4). During the rainy season, decreasing abundance of T. minor and B. browni (Fig. 3) was significantly correlated with increasing pH values at greater soil depths (T. minor: P <0.05, r=-0.970 for adults and nymphs, r=-0.951 for nymphs only and P <0.01, r=-0.994 for adults only; B. brown: P<0.01, r = -0.998 for adults and nymphs and r = -0.995 for nymphs only; n = 4, respectively). In M. tridens, the increasing abundance of nymphs at greater soil depths was significantly correlated with decreas- ing soil moisture content (P<0.05, r= -0.977; n= 4). The decrease in abundance of adults, however, was significantly correlated with the decrease of the soil temperature at greater soil depths (P<0.05, r = +0.962; n = 4). This was also ob- served for nymphs of 7. minor (P<0.05, r = +0.951; n = 4). Neoteny and potential par- thenogenesis were confirmed for M. tridens, with sexually mature tritonymphs (= males) being ab- sent (cf. Adis and Mahnert, 1990a; Mahnert, 1985). PRIMARY ForEsT ON WuiTE SAND SOIL Pseudoscorpions accounted for 3-4% of all arthropods extracted from 1m? soil of 14cm depth (14,000-15,000 ind./m?, Acari and Collembola disregarded) in the study area (Adis et al., 1989a, b). During the dry season, about 48% of the total 530 (+ 22) pseudoscorpions were collected from the top 3.5cm, 27% from 3.5-7cm, 12% from 7-10.5cm (= humus layer) and 13% from the white sand soil layer (10.5-14cm). About 66% of all specimens collected represented juvenile stages (Fig. 4: nymphs). Decreasing abundance of pseudoscorpions at greater soil depths was significantly correlated with decreasing soil moisture content (P<0.05; adults and nymphs: r = +0.965, adults only: r = +0.952; n=4) and decreasing soil temperature (P<0.05; adults and nymphs: r = +0.967; n=4). During the rainy season, vertical distribution was similar but more pronounced (Fig. 4): 73% of the 480 (+ 27) pseu- doscorpions were taken from the top 3.5cm, 11% from 3.5-7cm, 7% from 7-10.5cm and 9% from the white sand soil layer (10.5-14cm). About 68% of the total catch were nymphs. No significant correlation was found between the vertical dis- tribution of pseudoscorpions and changing con- ditions of soil moisture content, soil temperature and pH. Seven species of pseudoscorpions were ob- tained during the dry and six species during the rainy season (Fig. 5). All were previously reported from soils of Amazonian dryland forests (Mahnert and Adis, 1985). Chthoniidae were most abundant, with Tyrannochthonius (T,) minor Mahnert (dry season: 231413 ind/m’, rainy season: 154415 ind. /m?), T. (T.) rotun- dimanus Mahnert and Pseudochthonius homodentatus Chamberlin accounting for 33- 45% of the total catch (Fig. 5). Syarinidae was the next most abundant family with Microblothrus tridens Mahnert (dry season: 164+ 10 ind./m’, rainy season: 135+8 ind./m*) and Ideobisium schusteri Mahnert (dry season: 2943 ind./m?, rainy season 14+4 ind./m’) accounting for 31- 36% of the total catch. The Miratemnidae were represented by Brazilatemnus browni Muchmore (17-35%; dry season: 9146 ind. /m*, rainy season: 168+ 16 ind./m? ). Less abundant (< 1%) NEOTROPICAL PSEUDOSCORPIONS DRY SEASON 2 Nim ws 68 9.6 Li Ideobisium schusteri = Nim*=268 =Nim@= th.4 Nin? 681144 192 96 120.3 48 241 19.2 100 Brazilatemnus browni a = Nim? = 913 = Nin? = 168-4 o ec 5 so oO —_ fet Oo -35 -70 405 140 Soil Depth (cm) 3.5 -70 405 44.0 [ej] =nymphs [J = adults RAINY SEASON 16.4 437 DRY SEASON RAINY SEASON 2 Nim”; 154.052.919.228 1299 24.1 “3 Tyrannochtonius minor = Nim? =230.9 = Nim = 154.0 Nim? 24) 722192 481 770 244 96 244 1 m Microblothrus tridens = Nim@= 163.6 = Nim@= 134.8 -35 -70-10.5-14.0 Soil Depth (cm) -3.5-7,0 405-140 FIG, 6, Vertical distribution of four species of pseudoscorpions in soil (9%). Samples taken every 3.5cm to depth of I4cm during dry and rainy seasons in primary dryland forest on white sand soil near Manaus, Brazil. Total catch of each season = 100%. Abundance given for each soil layer (N/m*) and for total catch per season (=N/m*). were Ideoroncidae (Albierix gracilis Mahnert) and Chernetidae (Pseudopilanus crassifemoratus Mahnert), The same four species (T. minor, B. browni, M. tridens and I. schusteri) were the most abundant in both seasons, however, their dominance in the total catch per season varied (Fig. 5). In two species, vertical distribution dif- fered with the seasons. During the rainy season, T. minor and [. schusteri were found only from 0-7em and in the top 3.5cm of soil, respectively. Both species were found throughout the 0-14em soil sample during the dry season (Fig. 6). Their abundance was greatest in the top 3.5em, inde- pendent of seasons. This is also true for B. brawni Which, together with M_ tridens, occurred throughout the 0-14cm soil sample during the dry season as well as the rainy season, Adults of M. tridens were somewhat more abundant in the top 7em, whereas no adults of J. schusteri were col- lected, probably due to low catch numbers. A. arboricola was restricted to the top 3.5cm. During the dry season, significant correlation be- tween abundance and soil conditions was ob- served in 7. minor: its abundance decreased at greater soil depths as the soil moisture content (P<0.05, r= +0.979 only for adults; P<0.10, r= +0.935 for adults and nymphs, r = +0.900 for nymphs only; n = 4, respectively) and the soil temperature decreased (P<0,05, r = +0.967 for adults and nymphs, r= +0.972 for adults; P<0.10, t=+0.939 for nymphs only; n =4, respectively). No significant correlation was found during the rainy season between the vertical distribution of species and the abiotic factors investigated. In M. tridens sexually mature tritonymphs (= males) were absent, which confirms neoteny and poten- tial parthenogenesis in this species (cf. 4.1.). DISCUSSION In Central Amazonia the abundance of pseudo- scorpions in primary and secondary dryland forests on yellow latosol accounted (inde- pendently of seasons) for 3-5% of.all arthropods 438 extracted from Im? soil of I4cem depth and for 10-15% when Acari and Collembola were ex- cluded (cf. Adis et al., 19873, b. unpublished data). In the prmary forest on white sand soil, their abundance was only 0.7-0.9% and 3+4%, respectively, due to large numbers of Pauropoda and Dipluta (cf. Adis er ai., 19892, b). About two-thirds of all pscudescorpions recovered from the soil of the primary and secondary forest on yellow latosol (61-67% of the total catch) and about three-quarters of the primary white sand forest (75-84%) inhabited the lop 7em. No species were found to vecur exclusively in the lower, mineral subsoil (e.g. in 10.5-I4cem soil depth). Two species (7. minor, B. browne) were more abundant in the upper, organic layer in the three forests which were investigated (Figs 3, 6; fig. 3 in Adis and Mahnert, 1990a), M4. rridens, T. minor and B, frewai were the most abundant species, representing 89-95% of the total catch in the primary forests on yellow latosol and on white sand soil. They represented 58-74% of the total catch in the secondary forest on yellow latosol, where J. senuis and A. gracilis were frequent as well (22-33% of the total catch; cf. Adis and Mahnert, 1990), The similar spectriim of pseu- doscorpion species in forests on ycllow Latosol and on white sand soil and especially the lack of endemic species in the latter forest type. confirm the geological results of Chauvel et af. (1987). They reported that the white sand area inves- tigated represents the final stage of pexizolisation, Le. the transformation of clayey latosols to white sandy podzols by (long-term) wealhering end leaching processes. If the while sand anca were a lange dried-up old riverbed, species composition would be different from the yellow latosol area (ef, Adis and Mahnen, 1990b). Neither during the dry nor the rainy season was the abundance of pseudoscorpions in mineral subsoils higher in response to the changing mwis- ture content in organic layers, This phenomenon has been reported in arthropods in the seasonal- ly 0.01) and between area of the island and the number of 449 species present (Fig. 3.2: r= 0.716, p>0.001). Tn bath eases there is a significant correlation. ORIGIN OF FAUNAS As the distance from an island from the main- land inereases, its component of continental species decreases. Very striking ts the much lower percentage of continental species on the African islands as com- pared to those of the Pacific. The same is ime for the southern Pacific islands Juan Fernandez and Easter Island. This could be explained by their isolated position, Juan Femandez lics in the mid- dle of the northerly directed Humboldt Current, whereas Easter Island is situated a long distance from the continent in the centre of the South Pacific Gyre, rnaking the arrival by rafting rather unlikely. The presence on the Galapagos islands of northem, central {with Antillean elements), as well as southern Amencan elements, could be explained by their special situation astride the equator. The archipelago lies in such a position that itis reached by the warm Nifio Current in the rainy season and by the cold Humboldt Current in the dry season. The Californian Current of the Norhern Hemisphere runs southwards along the North American coast and reaches the Panama Basin where it is warmed up and tums towards the Galapagos as the Nine Current. The southern Humboldt Current runs northwards along the south Amencan coast and tums westward near the equator towards the Galapagos. Rafts can easily be transported from the north as well as from the south. A floating rafi takes about two to four weeks to reach the islands from the South American mainland (Schatz, 1991). Furthermore, there was a broad connection be- tween the Caribbean region and the eastern Pacific area from 48 my until 3.8 -3 my ago (Woodring, 1959; Jones and Hasson, 1965) with a sea current running from the Atlantic to the Pacific (Petuch,1982). The Panama isthmus was plugged some 3 my ago by the Canbbean Plate which was shoved in between the north and south American plates. At that time the Galapagos is- lands had already emerged from the sea. It is acceptable that many fauna elements of the Caribbean reached the Galapagos at that time, Nearly 82% of the known spider species of Cocos Island are continental species. The Marquesas have more species of Pacific origin. This can be expected because of the posi- tion of this archipelago at the margin of the Polynesian province (NE end of the south 450 MEMOIRS OF THE QUEENSLAND MUSEUM SIZE FREQUENCY DISTRIBUTION IVORY COAST zuBaeees %) FREQUENCY ( SIZE CLASS (mm) il, 0 6 2 2 “ * re) SIZE CLASSES GALAPAGOS axe SIZE CLASSES SECHELLES Py Ba 2 ‘ i ar ie ae cr ee SIZE CLASSES COCOS SIZE CLASSES SAINT HELENA SIZE CLASSES HAWAII 2 7 ‘ 6 8 . 8 feauS eeu SIZE CLASSES PASQUA SIZE CLASSES MARQUESAS SIZE CLASSES JUAN FERNANDEZ FIG. 2. Frequency distribution histograms of total body length (over 2mm size classes) for each island or archipelago. equatorial archipelagos chain). In contrast, Hawaii and Galapagos have only a low percent- age of Polynesian species as the distances be- tween them and the Polynesian archipelagos are too extensive. The term ‘endemic’ must be used now with great care because the continental faunas are far from being well known. This is especially so for the neotropical spider fauna. Many regions have Continental been sampled only superficially or not at all. Few families have been thoroughly revised and new studies will be needed once the ‘black holes’ have been filled. For instance, the figures in table 2 for Galapagos are based upon 70% of the total of the Pacific Marquesas Arch. (MA) Island/Archipelago Ss S/area distribution _ | origin ae litan Endemic Cocos I. (CO) 30 0.63 82% (A) 18% Galdpagos Arch. (GA) 146 | 0.02 32% (A) 4% 9% 60% Hawaii Arch. (HA) 168 | 0.01 11% (A) 5% 19% 64% 31% 20% 50% Juan Fernandez I. (JF) 32 17% (A) 17% Easter I. (PA) 23 0.14 22% (AU) 66% Seychelles Arch. (SE) 131 [0.48 9% (E) 18% 65% St Helena I. (SH) 98 0.81 7% (BE) 44% 45% recognised species. Hence, 46 species have yet to be identified. At this stage in our knowledge one is never sure that the species one describes from an oceanic island really has a dispersion restricted TABLE 3. The spider fauna of islands and archipelagos. Percentage of species with distribution 1° continental (A=American; E=African; Au=Australian), 2° cos- mopolitan and 3° species known only from island or ‘Endemic’. Values based only on described species. SPIDERS OF OCEANIC ISLANDS altitude/species relationship log species 24 log altitude Area/species relationship log area FIG. 3. 1, 2. Relationship between no. of spider species (N) and: 1, altitude (highest elevation) of island or archipelago (logN =-0.6224 log alt.(m)); 2., island/ar- chipelago area (logN = 0.2686 log area + 1.0269). to that island for it may not yet have been found on the continent. We may therefore seriously question whether we can validly use the propor- tion of endemics for the analysis of an island fauna. However, we consider that the percentage of endemics we now recognise reflects the rough proportion of real endemics that will eventually be shown to exist. Cocos Island seems to have few (18%) ‘endemic’ species. It lies relatively close to the continent. Once the distance to the continent ex- ceeds 900km, we find an ‘endemic’ proportion in between 50 and 65%. The high percentage of ‘endemics’ on Hawaii (64%) is probably due to its old age and thus the long period of isolation of the archipelago. The high percentage for the Galapagos islands (60%) may perhaps be due to the fragmentary knowledge of the South American spider fauna (the main reason why one third of the Galapagos spider fauna is not yet identified). The high percentage (70%) of ‘endemics’ on 451 island altitude vs. Linyphiidae species number of species 16 2,000 3.000 altitude (m) 5,000 relationship area/species Linyphiidae number of species 16 log area FIG. 4.1, 2. Relationship between no. of linyphiid species (L): 1, and altitude (L = 0.0035 alt(m) + 1.0544; 2., and island/archipelago area (L = 3.7886 log area - 4.0344) (separate islands in archipelagos). (S =no. species). Juan Fernandez is very striking. Though close to the mainland, it is a rather isolated island (Hum- boldt Current) with an environment rendered harsh by the very special climatological condi- tions. The proportion of cosmopolitan species on the islands varies between 0 and 20%, with two strik- ing exceptions: Saint Helena with ca 44% and Easter Island with 60% (this figure is based on only 10 species). Most of these species are intro- duced and restricted to human settlements. This shows the great impact man has had on the spider fauna of Saint Helena. All the islands considered here do have human settlements, native on Hawaii, Easter Island and Marquesas, but immigrated in historical times on the others. Human settlements invariably result in deforestation for arable land and subsequent in- troduction of ubiquitous species. Most often this is detrimental to the original fauna. Even more damage can be done with the introduction of domesticated animals (cattle, dogs, cats, rodents, etc.) and cultivated plants. Accidental introduc- tions can also have Serious consequences as for instance the Little Fire Ant (Wasmannia auropunctata) on Galipagos. This species haunts large areas, devastating nearly all living animal Organisms. QUALITATIVE ANALYSIS Qualitative analysis of the distribution of par- ticular groups on islands is perhaps more reveal- ing than Sree yaie analyses which are still hampered by the incompleteness of many data sects. Spiders that do not balloon do not seem well adapted to colonise oceanic islands. Good ex- amples are seen in the Zodanidac. Only four species, if we include Cryptorhele, are present on the islands considered. On the Seychelles we find the endemic Cryptothele allwandi Simon; the Comoros have Asceua radiesa Jocqué on Grande Comore and Diares seiugates Jocqué on Mohéli (Jocqué, 1986). Zedarion frispinosum Suman is known from Hawaii. The presence of 4 Zodarion on Hawaii, completely outside its main distnbu- tion is puzzling. but is probably explained by an introduction as is the presence of Z. fulvonigrum (Simon) in North America. The Mygalomorphae are found only on two of these archipelagos, Six species in three families (Benoit, 1978) occur on the Seychelles. Five of these are endemic, the sixth species, Idioctis intertidalis (Legendre and Benoit), is also found on Madagascar and Grande Comore, where it occurs together with the en- demic Moggridgea nesiota Griswold. The presence of these spiders, ull but one apparently true endemics, on the Seychelles is explained by its granitic nature, which implies that they have had a fauna from the moment they were separated from the continent. The Comoros are probably more easily colonised than other islands, possibly by rafting, as that archipelago is close-to its source area, Madagascar, for which the spider fauna is unfortunately poorly known. Linyphiidae can be considered excellent colonisers mainly because many frequently bal- loon. However, linyphiids appear to be able to occupy few habitats. Jocqué (1984. 1985) ex- plained that interference competition in tropical lowland with ants is apparently 100 important to allow the presence of many linyphiid species. As ants are less common at higher altitude many more linyphiid species tend to be present in high- land than at low elevations (e.g. Scharff, 1992). (Since ant diversity and density are linked to MEMOIRS OF THE QUEENSLAND MUSEUM climatic conditions, the impression may exist that they are the determining factor.) The presence of an important number of Linyphiidae on high is- lands was already illustrated for the Comoros (Jocqué, 1985). This is particularly tue for is- lands. There is a significant correlation between the altitude of island and the number of species of Linyphiidae present (Fig. 4.1: r = 0.780, p< 0.001) and between area of the island and the number of linyphiid species present (Fig. 4.2: r= 0.688, p< 0.001). There is a third aspect relevant to the colonisation of islands: parapatric specia- tion on the spot. The Lycosidae are a good ex- ample. Wolf spiders might be expected to be good colonisers. Their juvenile stages are active bal- looners, and transport by rafting is also a likely means of dispersal if only because lycosids are very commen on banks of rivers and in marshes from where rafts are supposed to be derived. However, the number of insular species is quite low compared to the high number of species in continental tropical areas. (Galapagos: 6 species; Hawaii: 11; Covos: 1; Juan Fernandez: 2; Saint Helena: 7; Seychelles: 2: Comorés: 3). Moreover, almost all species from istands in this study have no continental distribution and must be con- sidered endemics of each tsland. Only Bristowiet- la seychellensis (Bristowe) is known from both Seychelles and Comorés. Their apparently high speciation rate may be related to this. OF special nole, some species at high altitudes on some islands are apparently derived from species at low altitudes, A well documented case is that of firjs- towiella on the Comoros where two closely re- lated species have clearly differentiated habitats: Bristowiella seychellensis living in short grassy vegetation from sea level to about 1500m and Bristowtella kartalensis Alderweireldt living in recent Java flows with sparse vegetation from about 600m upwards (Alderweireldt, 1988). Another interesting case is that of the Hawaiian cave dwelling lycosids which have strongly reduced eyes or none and which clearly speciated on the islands themselves (Gertsch, 1973). On Galapagos, a group of six species apparent- ly derived from the most common one (*Lyc 3°). it occurs over the whole archipelago and occurs mainly in coastal salt marshes. Another species (‘Lyc5') occurs only on the low island Espaiiola. The four other species are confined to the high pampa zones of the volcanoes Sierra Negra and Cerro Azul (‘Lye 1°) on Isabella, on San Cristébal {‘Lyc 2°), on Santa Cruz (*Lyc 4") and the Aleedo valcano on Isabella (‘Lyc 6"). The reviston of this remarkable species-group is in preparation. SPIDERS OF OCEANIC ISLANDS A fourth example of such segregated parapatric populations is found on Juan Fernandez where 2 Lycosa species are found, one living along the coast, the other living in the higher pampa zone. These statements reveal three important factors influencing the composition of island faunas. In the first place, there is the accessibility of the island, mainly its distance to a source area. In the second place, the diversity of the island’s habitats is important. Particular spiders such as mygalomorphs and zodariids are only present on those islands that are easily reached or already had a fauna when they became isolated. Other families, although good colonisers, appear to be restricted by the ecological conditions of the is- land they can reach. Speciation appears to be the third factor which may be important in the colonisation of habitats that can hardly be reached by the normal ways of dispersal. The effect of niche pressure (Jocqué, 1982) is likely to be an important mechanism in this respect. CONCLUSION The faunal composition we now find on many islands is far from being natural. At the same time we know little about the arthropod fauna of most oceanic islands. This makes the analysis and comparison of the faunas very hard. The in- fluence of speciation processes is probably large- ly overlooked in connection with the compensation of extinction. LITERATURE CITED ALDERWEIRELDT, M. 1988. On the genus Bris- towiella, with the description of B. kartalensis n. sp. from the Comoro Islands (Araneae, Lycosidae), Bulletin of the British Arachnological Society 7: 269-272, BAERT, L., MAELFAIT, J.-P. & DESENDER, K. 1989a. Results of the Belgian 1986 -expedition: Araneae, and provisional checklist of the spiders of the Galdpagos archipelago. Bulletin van het Koninklijk Belgisch Instituut voor Natuur- wetenschappen 58: 29-54. 1989b. Results of the Belgian 1988-expedition to the Galapagos islands: Araneae, Bulletin van het Koninklijk Belgisch Instituut voor Natuur- wetenschappen 59: 5-22. BENOIT, P. 1977, Araneae, Introduction. In ‘La Faune terrestre de Tile de Sainte-Héléne. Quatriéme partie’. Annalen van het Koninklijk Museum voor Midden-Afrika, Zoologische Wetenschappen 220: 12-188. 1978a. Contributions 4 I’ étude de la faune terrestre des iles granitiques de l’archipel des Séchelles. 453 Introduction. Revue de Zoologie Africaine 92: 390-404. 1978b. Contributions a 1’ étude de la faune terrestre des iles granitiques de l’archipel des Séchelles. Araneae Orthognatha. Revue de Zoologie Africaine 92: 405-420. BERLAND, L. 1924. Araignées de l’ile de Paques et des iles Juan Fernandez. In “The Natural History of Juan Fernandez and Easter Island’. Vol. Ill, Zoology: 419-437. 1935. Araignées des files Marquises. In ‘Marquesan Insects-II’. Bernice P. Bishop Museum Bulletin 114: 39-70. 1939. Nouvelles araignées marquisiennes. In ‘Mar- quesan Insects-III’. Bernice P. Bishop Museum Bulletin 142: 35-63. GERTSCH, W. 1973. The cavernicolous fauna of Hawaiian lava tubes. 3. Araneae (Spiders). Pacific Insects 15: 163-180. HOGUE, C. & MILLER, S. 1981. Entomofauna of Cocos Island, Costa Rica. Atoll Research Bulletin 250: 29pp. JACKSON, M. 1985. ‘Galapagos, a natural history guide’. (The University of Galgary Press). JOCQUE, R. 1980. ‘Verspreidings-, aktiviteits- en groeipatronen bij spinnen (Araneida), met spe- ciale aandacht voor de arachnofauna van de Kalmthoutse heide’. (Doctoraatsverhandeling Rijksuniversiteit Gent). 181 pp. 1982. Niche pressure and the optimum exploitation hypothesis. Biologisch Jaarboek Dodonaea 50: 168-181. 1984. Considérations concernant I’ abondance rela- tive des araignées errantes et des araignées A toile vivant au niveau du sol. Revue Arachnologique 5: 193-204. 1985. Linyphiidae (Araneae) from the Comoro Is- lands. Revue de Zoologie Africaine 99; 197-230. 1986. Ant-eating spiders from the Comoros (Araneae, Zodariidae). Revue de Zoologie Africaine 100: 307-312. JONES, D.S. & HASSON, P.F. 1965. History and development of the marine invertebrate faunas separated by the central american isthmus. Pp. 325-356. In Stehli F.G. and Webb S.D. (eds). “The Great American Biotic Interchange’. MACARTHUR R.H. & WILSON, E.O. 1967. “The theory of island biogeography’. (Princeton University Press: new Jersey). 198pp. PETUCH, E.J. 1982. Paraprovincialism: remnants of paleoprovincal bounderies in recent marine mol- luscan provinces. Proceedings of the Biological Society of Washington 95: 774-780. SAARISTO, M. 1978. Spiders (Arachnida, Araneae) from the Seychelle Islands, with notes on taxonomy. Annales Zoologici Fennici 15: 99-126. SCHARFF, N. 1992, The Linyphiid fauna of Eastern Africa (Araneae, Linyphiidae). Distribution, pat- terns, diversity and endemism. Biological Journal of the Linnean Society 45: 117-154. SCHATZ, H. 1991. Arrival and establishment of Acari 454 MEMOIRS OF THE QUEENSLAND MUSEUM on oceanic islands. Pp. 613-618. In Dusbabek F. SUMAN, T. 1964. Spiders of the Hawaiian Islands: and Bukva, V. (eds). ‘Modern Acarology’. Vol. 2. Catalog and Bibliography. Pacific Insects 6: 665- (Academia, Prague and SPB Academic Publish- 687. ing: The Hague). 1965. Spiders of the Family Oonopidae in Hawaii. SKOTTSBERG, C. 1920. Notes on a visit to Easter Pacific Insects 7: 225-242. Island. Pp. 2-20. In ‘The Natural History of Juan WOODRING, W.P. 1959. Geology and paleontology Fernandez and Easter Island’. Vol. 1. of canal Zone and adjoining parts of Panama. 1954. A geographical sketch of the Juan Fernandez Description of Tertiary mollusks (Gastropoda: Islands. Pp. 89-192. In ‘The Natural History of Vermetidae to Thaididae). United States Geologi- Juan Fernandez and Easter Island’. Vol. 1. cal Survey Professional Paper 306: 147-240. THE REPRODUCTIVE ECOLOGY OF EUSCORPIUS FLAVICAUDIS IN ENGLAND T.G, BENTON Benton, T.G. 1993 11 11: The reproductive ecology of Euscorpius flavicaudis in England. Memoirs of the Queensland Museum 33(2): 455-460. Brisbane. ISSN 0079-8835. The reproductive ecology of the scorpion Euscorpius flavicaudis was studied both in the field in England (at a colony dating back 120 yrs), and under semi-natural conditions in the laboratory. Before the mating season males become vagrant to search for females. On encountering a pregnant female or one with young, inher ‘burrow’ , the male may mate-guard her until her period of maternal care ends and she becomes receptive to him. Large males have a higher mating success than small males. Two instars of adult males exist in this population of scorpions: large 7th instars and smail 6th instars, and the reasons for this pedal paradoxical situation ate explored. QEuscorpivs, mate-guarding, niaring, life- ISTOFY, .G. Benton, Department of Zoolagy, University of Cambridge, Dawning St., Cambridge, CB2 3EJ, United Kingdom; present address: School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom; 7 December, 1992. Evolutionary and behavioural ecology are rela- tively young disciplines; and have to date con- centrated on using the more ‘familiar’ animals as subjects: birds, mammals and insects. These dis- ciplines have largely passed arachnids by, In- creasingly, however, we are beginning to realise the utility of arachnids as model animals in help- ing to elucidate general evolutionary principles. Although there has been considerable increase in behavioural ecological interest in spiders in recent years, scorpions have been largely ig- nored, This is perhaps because they are difficult animals with which to work — long-lived, inae- tive, elusive and nocturnal. This paper outlines some of the main findings of a study of scorpion reproductive ecology. It is unfortunately incom- plete: posing more questions than it solves; but, T hope that it illustrates the fact that, as in so many areas of their biology, scorpions are idiosyncratic, fascinating and more complex than they may first appear. This study combines the power of controlled laboratory experiments and the ease of laboratory observations with the reality of what is observed in the field; and, by so doing, for the first ume the events surrounding the courtship of a scorpion are explored and placed in an ecological context. THE STUDY ANIMAL Euscorpius flavicaudis (de Geer), common throughout southern Europe (Birula, 1917), also occurs in England, most probably as a result of introductions. This species is a successful colonising species (Fage, 1928; Wanless, 1977; Lourenco & Vachon, 1981) and is often found associated with buildings (Wanless, 1977). Colonies have been reported from several loca- tions in England, but only one, at Sheerness Docks, Kent (51°26'N, 0°45’) has lasted many years and is of considerable size. The first record of scorpions at Sheemess is a label ona specimen of Euscerpius flavicauadis in the Natural History Museum, London: “Taken in Sheerness Dack- yard. 1870, J.J, Walker’ (P.D. Hillyard, in lit.). METHODS FreLD OBSERVATIONS At Sheerness Docks, most present buildings and the penmeter wall date from 1823 (Benton, 1992a). Scorpions are common in areas little frequented by people; and are especially common living in the perimeter wall. This old wall is abeyut 4m high and 66cm thick. It shows the effects of time, with the mortar between the bricks crum- bling away, creating ‘cracks’ which the scorpions readily inhabit, My study area was a 104m length of perimeter wall (bounding ornamental and vegetable gardens). The field study was con- ducted from January 1988 to July 1989. during which 92 visits were made to Sheerness Docks (totaling 500 hours of observations). Scorpions were observed using a portable ultra-violet light. Benton (1992a) details field methods, LABORATORY OBSERVATIONS To allow more complete observations and ex- petimentation a laboratory colony of Euscarpius Was sel up, modelled on the habitat at Sheemess- This consisted of a plywood wall (2.44m x §.79m), covered in sandpaper, with 144 slots (2.5 456 x 5, lem) cur into the face. Into these slots were fitted artificial ‘cracks’ 12 cm long. These were open to the wall and closed at the far end. A layer of soi) was placed at the base of the wall. This soil was pervodically damped ta mimic rain; and each week woodlice (the scorpion’s natural food) were released onto it. This colony was kept under a natural photoperiod. and as near natural tempera- ture and humidity as possible, Observations and experiments were conducted at night, when the wall was illuminated by lamps fitted with deep- red filters (invisible to scorpions: Machan. 1968). Unless bemg used inan experiment, the scorpions (collected at Sheerness) were allowed to move freely around the wall. Benton (1991a) details colony setup. EXPERIMENTAL. MeTHOoDS In this study of male contest behaviour for temales during the mating season, || males were used, On the artificial wall 40x 40cm enclosures were made around a single crack. A female car- rying young was placed in this crack, and tater an experimental male was added. Thirty minutes after this male had encountered and entered the crack a second male was added. After encounter- ing the crack the second male would attempt to enter. The males would then meet, assess each other and fight. This procedure was then imme- diately repeated. The two replicates constituted a ‘contest’ (and in all cases the results were unam- biguous, and identical for each replicate). [n total 110 contests were conducted (with each male as ‘owner’ against every other male as intruder). Contest order was randomly selected. Other methods are detarled in Benton (19926). and scor- pion mensuration in Benton (1991b). RESULTS BACKGROUND Like most scorpions, £. flavicuyedis is noctur- nal. During the day and over the winter, they are not visible as they have retreated to the back of their cracks in the wall. At night, depending on the season, most scorpions evident are at the entrance to their cracks where they remain im- mobile, with their claws outstretched and open, The most common prey items are isopods (Par- cellio scaber) (64%) and then conspecifics (12%) (Benton, 1992a), SEASONS Scorpion activity at Sheerness is highly seasonal, Over the winter very few (if any) can be MEMOIRS OF THE QUEENSLAND MUSEUM seen, The numbers build up during the spring and peak in late summer (Benton, 19924) before decreasing again to winter levels, As these scur- pions live for several years (Benton, 1991b) this pattern reflects varying pattems of behaviour, rather than gross mortality and natality. For most of the year, most scorpions seen are in their crack (for November to June only 8 + 11% of all seor- pions observed are out of their cracks). However, in summer, on average, 24+ 9% of scorpions observed were on the wall surface. Adult males make up most surface-active animals: 3-4x mure males are seen on the wall surface than adult females over the summer (Figs La, b), The number of females giving birth or with young peaks when female activity on the wall surface (Fig. 1a) is least. Females with young remain deep within their cracks, and were never observed to venture onto the wall surface, Indeed, females in the last stages of pregnancy also ap- peared to show a marked reduction in activity- Mast matings at Sheemess (Fig. tb) are just after the number of females with young peaks (Fig. Ja). Known females with young were found to be unreceptive to males until 241.2 days (n=12) after the juveniles had moulted and climbed off her dorsum (Benton, [992b). About 3 weeks after male surface-activity begins, the number of matings observed peaks (Fig. 1b). Only atthis time can males and females be found together in the same crack. These periods of cohabitation averaged 10+ 9.9 nights (range 1-30; n=19: data from field). Cohabiting occurred only prior to mating. and whilst the female was either carrying young, orin Jate preg- nancy (Benton, 1992b). Males were assocrated sometimes with females living in shallow cracks (n=3); in which case the males spent the day in a deep crack nearby and ‘commuted’ [o the female's crack to spend the night sitting at the entrance. The identity of the male mating with w specific female was known for 15 cases of cohabitation: in 14 the male had been recently cohabiting (P<0.005) with that female. Females of this species do not appear to assess males, and will mate with any male present when they be- come receptive (Benton, 1992b), If a male’s en- coumer rate with females is low, and a female's receptivity is predictable, then a male encounter- ing a soon-to-be receptive female may do better waiting for her to become receptive. rather than leaving her and risking trying to find a female nearer receptivity (Grafen and Ridley, 1983); and this seems to be the case with these scorpions (Benton, 1992b). This behaviour can also benefit REPRODUCTIVE ECOLOGY OF EUSCORPIUS FLAYICAUDIS Gaunt 400 Count FIG. |. Reproductive season of Euscorpius flavicaudis in England, 1988. (a) Seasonality of adult female surface-activity and no, of births. Female surface-ac- livity is smoothed over two weeks: nightly count shown as average of preceeding and following weck’s counts. No. of births (for each hali-month) estimated from no, of females giving maternal care, and date al which this ended. (b) Seasonality of adult male sur- face-activity (smoothed over two-wecks), and half- monthly count of no. of matings (observed no. of matings plus no. of spermatophores found). Data originally, in part, in Benton 1992b. the females for two reasons. Firstly.itensures that they are mated. Secondly, a major advantage of maternal care in Scorpions is to prevent predation of the juveniles (Benton, 19913), so havinga male at the front of the crack prevents entrance by other scorpions which may aid this role. Tn all cases of cohabitation, the male stations himself near the entrance, with the female behind him. Males attempting to enter the crack en- counter the currently cohabiting males, and each trics to grasp the other’s claws. Within a very few seconds one male retreats and flees from the crack. Males therefore fight for ‘possession’ of a ctack occupied by a female in the period before she becomes receptive. 457 To investigate male mate-guarding contests 110 contests were staged between 11 males (each male as ‘owner’ against each of the others as ‘intrider’). The proportion of contests won car- related very strongly with measures of scorpions size, and most strongly with pedipalpal claw length (r<=0.97, P<0.001). This ts to be expected as E, flavicaudis uses its claws as its main offen- sive weapon. In 80% of contests, the Jarger- clawed male won: when the smaller-clawed male won (20%), it was the ‘owner’ in most (91%) contests. Both relative claw-size and ownership status had highly significant effects on contest outcome (two-way ANOVA, size: F=68.5; df 1,36: P<0.0001; status: F=42.7; df 1,36; P<0.0001 ): large-clawed males usually won con- tests, but if contestants were closely matched in size then ownership status decided the outcome (giving an advantage equivalent to about 11% longer claws). Size AND SExuAL ADVANTAGE In the laboratory, males differed in reproduc- tive success: some males mated twice, some nce and some not at all. Larger males mated more often than small males (Fig. 2), This size ad- vantage is for two reasons. Firstly, as described above, larger males are better competitors for female-occupied cracks, Secondly, about 40% of matings are not preceded by mate-guarding. These fall into three broad categories: non-preg- nant females at the start of summer, females wot found by males before their maternal care has ended and (most rarely) females who have mated already (this is possible as a spermatocleutrum is not secreted in this species). Large males obtain more matings from all three categories than sma!) males, This is because, for each category of mating, females are initially unwilling to court. When a female is mate-guarded prior to her receptivity, she encounters the male frequently, and upon becoming receptive begins courting without aggression. Conversely, when a male encounters a non-pregnant female, or one without young he immediately attempts to court. The male grabs (or attempts to grab) the female's claws and stings her (Benton, 1990). Indeed, the start of a courtship (without mate-guarding) is indistinguishable from a cannibalistic attack. Large males are better at mating with these un- willing females as, unusually for scorpions, large males can be larger than females. In this species, and others (Polis, 1980), size (especialiy claw- size) is a good predictor of the outcome of can- nibalistic contests, Atthe start of courtship, males 458 Palp Length -0.5 0.0 05 1.0 15 2.0 Mating Success FIG. 2. Relationship between size (claw-length) and mating success in laboratory males free on wall sur- face (mean + SD). Difference between groups is sig- nificant (Kruskal-Wallis, H=11.4, P=0.003). sting females, and larger males can eat adult females (and often do: 10 cases observed in the laboratory), therefore, large males essentially give females the choice of being cannibalised or accepting courtship. Small males obtain fewer matings as they have a smaller (or nonexistant) size-advantage over females (Fig. 3) and there- fore are more likely to flee from those females who are not immediately willing to court. Size DimorPHIsM Sexually mature adult males are recognised by the secondary sexual characteristic of a notch in the pedipalpal fingers (Fig. 3). Adult males can differ markedly in size, and this is especially noticeable when one considers claw size, which increases allometrically with body size, such that larger males have disproportionately larger claws (Fig. 3). The frequency distribution of adult male claw sizes at Sheerness was dimorphic (Fig. 4). This dimorphism also occurs with other measures of size, such as prosoma length (Benton, 199 1b). This dimorphism probaly arises because there are two instars of adult male in the population at Sheerness: 6th and 7th (see also Benton, 1991b). DISCUSSION Two points are noteworthy. Firstly, the reproductive ecology of Euscorpius flavicaudis is much more complex than previously imagined. Naively placing pairs of scorpions together in a laboratory situation to watch the courtship would present a very misleading picture because the most significant behaviours occur before actual courtship. Precopulatory mate-guarding has not MEMOIRS OF THE QUEENSLAND MUSEUM trichobothria FIG. 3. Claws of two adult 3 d (a, b) and one adult 2 (c) same scale. Note secondary sexual characteristic: notch in fingers. been reported in scorpions, but is known to occur in some spiders (e.g. Vollrath, 1980; Watson, 1990) and occurs widely across the animal kingdom (Ridley, 1983). For precopulatory mate- guarding to evolve, males must gain an advantage by staying with a female prior to her becoming receptive rather than searching for a receptive female. Two criteria may determine this situa- tion: firstly, if a male can predict when a female is going to become receptive, and, secondly if receptive females are difficult to find. The former may occur if females become receptive following a moult (e.g. Watson, 1990), or as in the case of these scorpions, after maternal care. The latter criterion may result from female receptivity being very limited in time (e.g., in Gammarus female receptivity is limited to a brief period between moulting and the hardening of the amphipod’s exoskeleton: Grafen and Ridley, 1983), low population densities (and so low en- counter rates) or because of high male mortality REPRODUCTIVE ECOLOGY OF EUSCORPIUS FLAVICAUDIS Nuribar j ZaiZ ZY \Y VA A YA \7 ZV A e gga 8 85 8 § & YY = a 2 3 = # =-= & Pa oa a o i a & a ‘ Claw Jength imm? FIG. 4. Distribution of claw-sizes in adult dd is sig- nificantly non-normal, Filled bars are observed dis- tribution; stippled bars are expected normal distribution given mean and standard deviation of data. (x7=21.1, P<0.005). during mate-searching (Vollrath, 1980). The period of female receptivity is reduced where the paternity of a male is ensured by being the first male to mate with a female (so called first-male sperm priority), which may be common in arach- nids (e.g. Vollrath, 1980; Watson, 1990). A virgin female is far more valuable to a male than one which is already mated. Thus, Euscorpius flavicaudis, first-male sperm-priority and low population densities, coupled with the female's receptivity being predictable, may make it more profitable for a male encountering a female engaged in maternal care to male-guard her rather than risk searching for another female nearer receptivity, Secondly, there seems to be a paradox. Adult tales exist as lwo instars in the population. This itself is not a novel finding (see Francke and Jones, 1982). lis surprising that any males ma- ture at the smaller instar since the smaller males seem to be at such a disadvantage in obtaining mates. Natural selection would quickly eliminate any tendency to mature at a disadvantageous size. The paradox suggests two explanations. First, large males may have an advantage only in a mating season, As large males have more instars, they probably take longer to mature. Although males mate more m the short-term, the younger they mature presumably the more seasons in which to find mates. Perhaps there is a mixed evolutionarily stable strategy (ESS) such that the short-term gains enjoyed by ‘large males” are offset by the losses due to having one Jess season in which to mate, so thal, on average, the lifetime reproductive success of ‘large’ and ‘small’ males 459 is equal. This ESS could be maintained by fre- quency dependent selection (Benton, 1992b}: large males do relatively better when rare (as they suffer little competition) so their frequency is increased in the population by natural selection. However, when large males are common their gains are reduced, because of increased compeli- tion between them, to a point where they are offset by the cost of delaying matunty. Hence, an evolutionary equilibrium ts reached between the genes controlling maturation at the 6th and 7th instars. Secondly. an altemative explanation for this paradox is that there may be phenotypic plasticily in the maturation stage. A gene that can produce a variety of phenotypes depending on the en- vironment is said to exhibit phenotypic plasticity (Lessels, 1991}. The ‘optimal’ time at which to mature may depend on factors such as food availability, and thus growth rate (Stearns and Koella, 1986). For example, if food is plentiful, and an individual is large for its cohort it may be best to mature early. Conversely, if an individual is smail for its cohort then it may be better to delay matunty until more food is encountered. This seems to be the case in many spiders (e.g., Deevey, 1947; Vollrath, 1980). This subject will be discussed further elsewhere (Benton, in preparation), LITERATURE CITED BENTON. T.G. 1990. ‘The behaviour and ecology of scorpions,’ (Unpublished Ph.D, thesis, University of Cambridge.) 199] a, Reproduction and parental care in the scor- pion, Euscorpius flavicaudis. Behaviour 117: 20- 28 1991b. The life history of Euscorpius flavicaudis (Scorpiones, Chactidac). Journal of Arachnology 19: 105-110. 1992a, Determinants of male mating success in a scorpion. Animal Behaviour 43: 125-135 1992b. The ecology of Euscerpius flavicaudis in England. Journal of Zoology, London 226: 351- 368 BIRULA, A.A.B. 1917. ‘Scorpions: Fauna of Russia and adjacent countries; Arachnoidea, Volume 1- Scorpiones.' (Petrograd: translated from the Rus- sian by the Israeli Programme of Scientific Trans- lation, Jerusalem, 1965), DEEVEY, G.B. 1949. The developmental history of Latrodectus mactans (Fabr.) at different rates of feeding. American Midland Naturalist 42; 1&9- 219. GRAFEN, A. & RIDLEY, M. 1983. A inodel of mare guarding. Joumal of Theoretical Biology 102: 49-567. 460 FAGE, L. 1928. Remarques sur la dispersion en France et l’acclimation en France de I’ “Euscorpius flavicaudis” (De Geer). Association Francais pour l’avancement des sciences, La Rochelle 1928: 650-652. FRANCKE, O.F. & JONES, S.K. 1982. The life history of Centruroides gracilis (Latreille), Journal of Arachnology 9: 223-239. LOURENCO, W.R. & VACHON, M. 1981. Comple- ments a la description d’Acanthrothraustes brasiliensis (Mello-Leitao, 1931) (=Teuthraustes brasiliensis Mello-Leitao, 1931), synonyme d’- Euscorpius flavicaudis (Geer, 1778) (Scorpiones, Chactidae). Journal of Arachnology 9: 223-228. LESSELS, C.M. 1991. The evolution of life histories. Pp. 32-68. In Krebs, J.R. and Davies, N.B. (eds.) ‘Behavioural Ecology: an evolutionary approach’. 3rd Edition. (Blackwell Scientific Pub- lications: Oxford). MACHAN, L. 1968. Spectral sensitivity of scorpion eyes and the possible role of shielding pigment effect. Journal of Experimental Biology 49: 95- 105. MEMOIRS OF THE QUEENSLAND MUSEUM POLIS, G.A. 1980. The significance of cannibalism on the demography and activity in a natural popula- tion of desert scorpions. Behavioural Ecology and Sociobiology 7: 25-35. RIDLEY, M, 1983. “The explanation of organic diver- sity.” (Clarendon Press: Oxford). STEARNS, S.C. & KOELLA, J.C. 1986, The evolution of phenotypic plasticity in life-history traits: predictions of reaction norms for age and size at maturity. Evolution 40: 893-913. VOLLRATH, F. 1980. Male body size and fitness in the web-building spider Nephila clavipes. Zeitschrift fiir Tierspsychologie 53; 61-78. WANLESS, F.R. 1977. On the occurrence of the scor- pion Euscorpius flavicaudis (DeGeer) at Sheer- ness Port, Isle of Sheepey, Kent. Bulletin of the British Arachnological Society 4: 74-76. WATSON, P. J. 1990. Female-enhanced male competi- tion determines the first male and principle sire in the spider Linyphia litigiosa. Behavioural Ecol- ogy and Sociobiology 26: 77-90. COMPARATIVE POSTEMBRYONIC DEVELOPMENT OF ARACHNIDS ALAIN CANARD AND ROLAND STOCKMANN Canard, A. and Stockman, R. 1993 11 11: Comparative postembryonic development of arachnids. Memoirs of the Queensland Museum 33(2): 461-468. Brisbane. ISSN 0079-8835. A common model is used to describe the growth of various arachnid groups. In these predators there is retardation of development of the first instars, along with greater maternal care for the clutch and even, as far as some groups are concerned, in a viviparous develop- ment. Mites, which have very diversified biologies, have developments which have evolved in many different ways. Les développements des différents groupes d’arachnides sont décrits en suivant une trame commune. I] apparait ainsi une évolution des groupes de prédateurs qui se traduit par une augmentation du retard de développement des premiers stades, en liaison avec des soins a la ponte croissants, avec méme pour certains groupes des développements vivipares. Les Acariens, de biologies trés diverses, ont en conséquence des développements qui ont évolué dans des voies trés différentes. Development, arachnids, growth. Alain Canard, Laboratoire de Zoologie et d’Ecophysiologie, Université de Rennes I, France; Roland Stockmann, Laboratoire de Physiologie des Insectes, Université de Paris VI, France; 19 March, 1993. Analysis of developmental types used in arach- nids is very great diverse in the terms used to describe these phenomena. This diversity tends to partially hide some similar points in the develop- mental process. Authors often use terminology and analyse specific to a single group or species, instead of referring to general concepts relating to all arthropods. This study compares the developmental processes using the same terms, and we will only use specialised terms if itis absolutely necessary. All developments cannot be discussed in detail here; definitions and more precise descriptions can be found in Canard and Stockmann (1992). METHODS Our study is based mainly on literature, en- riched with our observations on arachnid growth, particularly on spiders and scorpions. First, we will evoke the main concepts and definitions used and will then define the different scales of development for each taxon. Taxa which are exclusively predatory are here represented by to the increasing level of care devoted to the clutch. Mites, which have diverse biologies, will be studied separately later. RESULTS CONCEPTS AND DEFINITIONS POSTEMBRYONIC DEVELOPMENT, HATCHING AND BIRTH The development, defined as initially embryonic, starts with the first divisions of the egg and continues with the formation of tissues. After hatching or birth, the development is qualified as postembryonic. The postembryonic organism is then covered with an external integu- ment and develops outside of the egg membrane or the female’s genital tract. Various organs ap- pear and develop, some will not be functional until late developmental stages (e.g. genital or- gans). Externally, the development is shown by changes in the cuticle. Reiteration of this concept may seem pointless, but the study of arachnids requires some explanations about hatching and birth. Hatching, i.e. the opening and release from the egg’s membrane, can be a long process. It may take a few days for some spiders, and sometimes some moults can be observed between the begin- ning of the opening of the egg’s membranes and their complete liberation. Hence, the post- embryonic period does start with the opening of the egg’s membranes. This does not make it necessary to look for a phenomenon before hatch- ing as, for example, Legendre (1958) and Vachon (1958b) did as they chose the ‘inversion’ to define the beginning of the postembryonic period. Moreover, this proposition has one drawback: it makes the postembryonic development begin at a time when the organism is not covered by a tegument. Birth appears as a well and easily defined phenomenon, without ambiguity. However, in pseudoscorpions, the organism leaves the female’s genital tract and moves into a ventral 462 | lifeon york freee, feeding cei fmy. a mt m4 re (css fa ae saa] toe FIG. 1. Stages of postembryonic deyelopment of an opilionid, Liobunum rotundum (Phalangidae, Pal- patores) (after Guental, 1943 and Naisse, 1959). (m= moult, Ji = incompleted juvenile, J = juvenile), brood pouch, which is like an external extension of the female's genital tract. Once in the pouch, development continues and the organism still receives nutritive fluid from the mother. There- fore, the start of the postembryonic development of pseudoscorpions should be when they leave the pouch, rather than when they leave the female’s genital tract, as others have stated, INSTARS AND STASES The instar is the organism between two moults. Generally, among arthropods, the external form does not significantly change between these two stages, except for the short periods of pre- and post-exuviation. However, among some mites, the external morphology and biology are modified while the cuticle remains. Hence, Henk- ing (1882) distinguished two forms, called instars (‘stade"), one active and the other motionless. Although this use of the term ‘instar’ was fol- lowed only by a few authors to describe the development of few mites, another acarologist (Grandjean, 1938), considered that the term was too indefinite and proposed the term “stase’. The definition of stase changed later, but this term is the basis for an evolutionary concept (Grandjean, 1954; André and Jocqué, 1986; André, 1989). We use ‘instar’ here in its usual definition, which means an organism between two moults (for endocrinal considerations, see Canard and Stockmann, 1992). To keep the general defini- tion, we will discuss the concept of stase later. When the animal presents separate biologies linked with two different aspects during the same instar, we call them ‘forms’ and give them two different names. SUCCESSION OF InsTars We limit our study to a mospho-biological description of the successive instars. These in- stars can follow each other in phase (Vachon. 1953) in which all instars are of same kind. These different types are defined in Table 1. MEMOIRS OF THE QUEENSLAND MUSEUM ie or f wilh oe tree life, heertiny cn yng di p— at week. 7 (< SIE at took 38) kad FIG. 2. Postembryonic development scheme of a sol- pugid, Eremobates durangonus (atter Muma, 1966). DIFFERENT DEVELOPMENTAL ROUTES OPILIONIDS The eggs are laid isolated from each other and then abandoned. The emergent animal depends on ats yolk reserves, It looks like a juvenile har- vestman but morphologically differs from fol- lowing instars by the unpigmented integument and tack of some characteristics, such as un- formed chelicerac, unsegmented tarsus, absence of median eyes, etc. Therefore it is an incomplete juvenile: Jii (tenm taken from Holm, [9460 con- ceming spiders) (= “larve’ according to Juberthie, 1965), It also has temporary organs (one of two eee teeth located on dorsum of cephatothorax). After the first moult, the animal differs from the imago only by its size and by sexual charac- teristics, Itis a juvenile. the second of the juvenile phase: Jz (= “nymphe' according to Juberthie. 1965). Although active, it still lives on its yolk reserves. After one moult, the juvenile apilionids (J3) scatter and then feed on prey they catch. Usually. 6-7 juvenile instars occur before it be- comes an imago, more rarely there are 5 to 8, The number of moulis may vary from with individuals of a species, and according to the developmental conditions; this number is generally the same for both sexes, On becoming a breeding instar (imagos) the opilionid cease moulting (adults), although some may live for be 5-6 years (Juberthie, 1965). SOLIFUGIDS The female isolates herself in burrow hur docs give care to her eggs. The animal which hatches is incomplete, mo- tionless and lives on its yolk reserves. [tis unpig- mented, has no eyes and no racquet organs, Twa types may be distinguished. The first is in the Galeodidae (Vachon, 1958a; Junqua, 1966). Tt docs not look like the imago and keeps the aspect it had while under the constraint of the membranes of the egg; it is a foetal instar; F (= ‘larve’ of Vachon, 1958a or Junqua, 1966, = ‘post-embryo’ of Muma, 1966). The second type is present in some Solpugidae (Lawrence, 1947) COMPARATIVE POSTEMBRYONIC DEVELOPMENT OF ARACHNIDS life on yolk with the mother free life, feeding on pray ears. oa J5 Nene J7 ars FIG. 3. Scheme of the different stages of the pos- tembryonic development of an amblypygid, Taran- tula marginemaculata (after Weygoldt, 1970). and some Karschiidae (Thaler, 1982). It looks like the imagos (juvenile), but lacks some struc- tures and has temporary organs like thorny con- tinuations of the legs. Itis an incomplete juvenile: Ji; (= ‘primarlarve’ of Thaler, 1982). A further moult results in an animal which has all the adult organs, except those linked with reproduction. This juvenile is, according to the species, the first or the second of the phase (= ‘nymphe’ of Vachon, 1958a; Junqua, 1966; Muma, 1966). It remains with the female until its integument is hard enough, then it disperses and lives on its own, feeding itself on prey it catches. The number of instars before reaching the status of imago varies according to the individuals. The imagos have a short life expectancy comprising only one instar (adult). AMBLYPYGIDS The female carries the eggs under its abdomen in a brood pouch generated by the genital tract during egg-laying. The incubation period of the clutch may last 3 months (Weygoldt, 1970). Hatching takes place in the brood pouch. The organism released from the egg’s membranes has a foetal aspect with the prosoma bent towards the abdomen and its appendages tight along the body. It is very incomplete (ap- pendages incompletely segmented, absence of setae and of sensory organs, etc.), motionless and lives on its yolk. It is a foetal instar: F (= ‘deutembryo’ of Weygoldt 1970). After one moult, the animals leave the brood pouch and attach themselves under the females’s abdomen. They still live on their yolk, can move, and look like imagos (juvenile), but some struc- tures are lacking and the internal organisation is incomplete (digestive tract, circulatory system, etc.). It is an incomplete juvenile instar which has particular organs on the legs, a dorsal continua- tion at the distal end of the tibiae (Weygoldt, 1970) and, in some families, an adhesive organ at the tip of the tarsus. It lives on the mother and is 463 life on yolk with the mother free life, feeding on prey hatching we en an FIG. 4. Scheme of the different stages of the pos- tembryonic development of Typopeltis stimpsonii (Thelyphonidae) (after Yoshikura, 1965). adapted to this life, so with reference to Scor- pions, we call it the pullus: JP (= ‘embryon’ of Pereyaslawzewa 1901, and ‘praenymphe’ of Weygoldt 1970). The pullus moult while on the mother and then leaves her. Through this moult it acquires all the characteristics of the adult (except the reproduc- tive organs). Itis a juvenile instar: J2. After a short gregarious period, the juveniles scatter and live on their own, feeding themselves. The number of juvenile instars may vary between individuals (Weygoldt, 1970) and, after one year, they be- come an imago. The imagos of both sexes go on moulting and, under good conditions, the females keep growing after this moult. Therefore, there are no ‘adults’. Uropyaips The female isolates herself in a burrow, and lays her eggs in a newly secreted transparent ventral sac. Hatching occurs in the brood pouch. It cor- responds to a quasi-simultaneous release of the egg’s membranes and of the integument of an instar similar to the foetal instar of the Amblypygids: F (= ‘primirlarve’ of Kastner, 1949 and ‘prelarva’ of Yoshikura, 1965). This instar, which was already formed in the egg, has a very short postembryonic life. The animal released after hatching and after the first moult, can move and climb upon the mother’s back. In general morphology, it looks like the adult (juvenile phase), but lacks some organs (median and lateral eyes are not yet visible, flagellum unsegmented, etc.). It has par- ticular organs linked with its life on the mother, including pad-like organs at the tip of the legs, instead of claws. It is a pullus: JP (= ‘sekondarlarve’ of Kastner, 1949; ‘larva’ of Yoshikura, 1965). After a ‘diapause’, there is a moult which releases a juvenile instar: J2 (= 464 different morphology from imagos themselves df active instar Non-breeding s same morphology as imagos Breeding (= imagos) TABLE 1. Characteristics of different kinds of instars. free life, feeding on prey FIG. 5. Scheme of postembryonic development of Prokoenenia wheeleri (after Rucker, 1903). ‘pullus’ of Kastner, 1949; = ‘protonymph’ of Yoshikura, 1965). They are still gregarious but move around the burrow and begin to feed them- selves. After one winter spent together, they then moult and scatter. Subsequent moults usually occur annually, but may be less frequent (Yoshikura, 1965). Imagos do not seem to moult (adults). Their size of each species does not vary much. life on yolk mi? m3 egg 2 Vian | J1 sina PALPIGRADIDS The sexual biology of palpigradids is almost unknown. Moreover, nobody has ever succeeded in breeding palpigradids. Therefore, knowledge about their postembryonic development is based on observations of natural populations. Under these conditions three immature instars have been determined for many species (Condé, 1984). The three instars of Prokoenenia wheeleri cor- respond to juvenile instars (Rucker, 1903). Their morphology evolves in a quantitative manner (number of bristles, articulations of the flagellum, evolution of genital parts, etc.). SPIDERS The degree of maternal care given to the clutch varies between species. Some spiders abandon their cocoon (e.g. araneids). Others carry it in their chelicerae or attached to their spinnerets. Characteristics motionless instars which do not feed several organs which do not function only non-functional genital organs MEMOIRS OF THE QUEENSLAND MUSEUM Symbols embryonal aspect unsegmented foetal instar incomplete ins ; i no temporary orgai juvenile temporary organs linked to life ullus on mother sg juvenile life on yolk in the mother's chamber in the cocoon hatching \ 38 ms m6 mz ma ‘i aA J3 {34 Pfs plae >| 37 be! os 98) [99 FIG. 6. Postembryonic development in two spider species that (a) abandons its clutch (Larinioides cor- nutus) (after Ysnel, 1992), and (b) cares for young (Philaeus chrysops) (after Bonnet, 1933; Canard, 1984). Others keep their clutch with them in their silk chamber (e.g. salticids). Hatching occurs in the cocoon and it some- times takes a few hours before the first instar is released. This instar is generally foetal: F (= ‘prélarve’ of Vachon, 1958b, = ‘pullus’ of Canard, 1984). Among some orthognathids it remains intrachorional and is therefore not pos- tembryonic. Its very thin cuticle bursts during hatching when the egg membranes open. Among several species which give care to the clutch, there is a series of 2 or 3 instars of this kind: Fj, Fo, F3 (Canard, 1987). As they cannot move, they stay in the cocoon. The following instars are mobile and look like a spider (juvenile) but the first one or two still lack some adult characteristics: they are incomplete juvenile (Ji) (= ‘larves’ and ‘prénymphes’ of Vachon, 1958b). In some cases, the first instar of COMPARATIVE POSTEMBRYONIC DEVELOPMENT OF ARACHNIDS life on yolk free life, feeding on prey hatching ‘ Z mi m2 m3 4) * fe He pal “a FIG. 7. Scheme of postembryonic development stages of ricinuleid Crytocellus palaezi (after Pittard and Mitchell, 1972). this phase is very incomplete, but in some others, some characters can only be shown absent using an SEM. These first incomplete juvenile instars live on their yolk, but some also feed on un- developed eggs, which they can pierce with a cheliceral blade. Dispersal takes place after the moult which releases a juvenile equipped with all its organs (J). Juveniles then live on prey they catch (= ‘nymphes’; Vachon, 1958b). The total number of juvenile instars may vary within a species. Males often become an imago in fewer instars than females. Female orthognathids and filistatids can still moult. In labidognathids, imagos do not moult any more (adults). In nature, all male spiders die without moulting. RICINULEIDS Hatching releases an active individual, which catches prey but which has only three pairs of legs and therefore does not present the general arach- nid characteristics. It differs from the imago, and is a larva: L. The three instars that follow resemble the imago, and possess 4 pairs of legs; however, they lack genitalic structures. They are juveniles instars: J1, J2, Jz (= ‘nymphes’ of Pit- tard and Mitchell, 1972). There is only one im- aginal instar (adult). PSEUDOSCORPIONS The eggs are laid in a brood pouch where they feed upon maternal nutrients with the aid of the embryonic membrane. Growth of the embryos bursts the chorion and the external side of the brood pouch to which they remain attached by the buccal region. Their form is not differentiated. Within a few seconds, the mother injects a nutri- tive fluid which trebles their volume (= ‘larves gonflées’ of Vachon, 1938; ‘deutembryons’ of Weygoldt, 1969). Organogenesis continues and a moult occurs which releases an animal which emerges by an anterior cephalothoracic tooth. The released instar looks like the imago, but 465 life with the mother on yolk or nutritive fiuids birth free life, feeding on prey FIG. 8. Postembryonic development of a pseudoscor- pion, Chelifer cancroides (after Vachon, 1938). retains some non-evolved characteristics (sen- sorial system, silk glands, digestive tract, etc.). It is an incomplete juvenile: Ji; (= ‘larve IT’ and ‘protonymphe’ of Vachon, 1938; ‘protonymph’ of Weygoldt, 1969). Some species apparently retain a foetal aspect (Judson, 1990). The first free instar sometimes remains and moults in the cham- ber constructed by the female (Weygoldt, 1969). The animal lives alone after this moult. The num- ber of following juvenile instars is fixed to two: J2 (= ‘deutonymphe’ ), J3 (= ‘tritonymphe’ ). Each instar can be identified through its trichobothriotaxy (Vachon, 1938). Imagos do not moult any more. ScorPIONS Eggs hatch in the female’s genital tract (viviparous species) or soonafter laying (ovoviviparous species). Newly born scorpions climb onto the mother’s back and remain there, living on yolk reserves. They resemble an adult (juvenile) but is incom- plete (without trichobothria, unpigmented in- tegument, without specific bristles, etc.). It has temporary organs linked to life on the mother’s back, such as legs without claws but bearing adhesive organs at their tip. This incomplete juvenile is a pullus: JP (= ‘larve’ of Vachon, 1940). After one moult on the mother’s back, the juveniles periodically move to the ground, where they begin hunting and eating for the first time. They disperse afterwards and live alone. The second instar is a complete one (Jz). The number of juvenile instars may vary according to sex. Mostly there are 6 to 7 instars, but it may vary from 5 (Orthochirus) to 10 (Diplocentrus) (Polis, 1990). Imagos do not seem to moult, but it may be possible (Stockmann, 1968). MITES The Acari have many more developmental sicesaaes weer me FIG. 9. Postembryonic development stages of a scor- pion, Euscorpius tialicus (after Angermann, 1957), types than other arachnids. The eggs are often abandoned. There is a first instar which has a foetal aspect, but it remains intrachorionic, ex- cept in some cases (Coineau, 1977). This instar can be compared with foetal instars of other arachnids (F), but it is not postembryonic. The first free instar is obviously different from the imago because it usually has only 3 pairs of legs, It moves and can feed itself. It is a larva: L. The following instars are eight-legged and only differ from the imagos by some quantitative or sexual characteristics: they are juveniles (J) (= “nymphes’ ). The number of instars is often fixed for a species, at | or 2, more often a maximum of 3, but up ta 4-5 in the Argasidae. After these immature instars imagos appear, which do not moult anymore (adults) (= “prosopon' of Reuter, 1909). In the thrombidiids, there are periods of inac- tivity between larval and juvenile stages and be- tween juvenile and adult stages. At such times, the animal is covered by the orginal cuticle, but secretes a new tegument under it, which becomes the tegument of the next instar. In many other cases, motionless instars can be distinguished, sometimes comparable to real nymphs or ta specific survival-forms, which allow for disper- sal. life on yolk or pee DISCUSSION AND CONCLUSIONS TERMINOLOGY AND Concerts Most terms used in other arthropods can also be used in arachnids. We have used only the original terms of pullus, foetal instars and incomplete juvenile. The foetal instar, although it has been defined for arachnids (Canard, 1987), is not specific to this group. It as evident in some insects and myriapods (= ‘prolarves’. ‘prélarves’, ‘pseudo- foetus’, etc.). The incomplete juvenile instars belong to the juvenile phase of which they form a part (Ji followed by Jz). One can recognize the sys- MEMOIRS OF THE QUEENSLAND MUSEUM lite on your free (fe, feading on ao _ OF Tristate eo aS i =) ele FIG. development of mites, (a) Argasidae, Ornithodoros 10. Succession of stages in postembrional maritimus (after Guiguen, 1990); (b) Oribatidae (Carabodes wilmamnni) (after Bellido, 1983), tematic group of the imago, therefore they are not larvae, but genital organs and furthermore some other structures are lacking. This ‘incomplete’ situation is not always easy to observe mor- phologically. However, biological information is useful, because these instars are nearly always unable to live on their own. The pullus (Paviovsky, 1924) is an incomplete juvenile instar with special adaptations to life on the mother, such as pad-like organs on the up of the legs. The presence of two morpho-biological forms during the same instar among mites is rare amongst the arthropods (except Diptera), but it does not raise any problems of description and does not require any fundamental vocabulary changes; it simply requires more accurate defini- tions, CHRONOLOGICAL AND MORPHO-BIOLOGICAL DESCRIPTIONS In the development of a systematic group of atachnids, except in ricinuleids, pseudoscorpions and perhaps palpigradids, there is no fixed num- ber of instars. Therefore it would be unwise to base a study on few species and to fix the chronology, because some still unknown developments may modify the established sys- tem, Theoretical systems of this kind were proposed by Reuter (1909) for mites and by Vachon (1958b) for spiders. Thus, the constant presence of three post-larval juvenile instars (=nymph) in mites stated by Reuter and often followed (protonymphe, deutonymphe, tritonymphe) does not conform to most species, COMPARATIVE POSTEMBRYONIC DEVELOPMENT OF ARACHNIDS in which there are less than 3 juvenile instars and even less to those with 4 to 6 instars (e.g. Or- nithedores maritimes), Developmental analyses based on a fixed num- ber of instars (chronological) establishes com- mon points between instars of different species, in order to envisage evolutionary pathways. But these common points will always remain hypothetical, and moreover, these pathways can be elucidated without this system. Therefore we do not wish to use a method with no decisive idvantages and, because of its fixed character, limited development descriptions, because species which do not suit the established system are excluded, In mites, for example, the number of instars is considered fixed to one larval, three juvenile instars and the adult. However, in many Species one of more juvenile instars are missing and sometimes there are more than three juvenile instars. For mites there is, depending on the species, a variable number of instars. EvDLUTIONARY PATHWAYS Immature instars of arthropods are adapted to special lifestyles or environments and sometimes differ from those of imagos. Often these adapta- tions influence the morphology so deeply that it is difficult to distinguish the imago from the immature forms (larva). Such differences are less marked among the arachnids (larvae absent ex- cept in mites and ricinuleids). A good correlate probably exists between the increased level of care by the mother to its clutch and the increased number of incomplete instars al the start of the development. Moreover, the biology and morphology of early instars can be observed and explained as adapta- ions to life in the cocoon or with the mother, e.g., the temporary organs such as distal, pedal pad- like organs of pullus (attaching to the mother) or the cheliceral blade of some incomplete juvenile spiders (feeding on undeveloped eggs). The viviparous cases do depend on the same kind of evolutionary processes, The evolution of many arachnids has probably been characterized by growing care of the clutch correlated with the increasingly and falter development of the first instars. Thus, the instars are both incomplete and regressed, because these adjectives depend on the point of view con- sidered: ontogenctic or evolutionary, This cor- responds to the “deux temps’ of Grandjean (1954) and, toacertainextent, tothe ‘state approach’ and the ‘stase approach’ of André (1989). Mites present great diversity in their biology 467 and, unlike other arachnids, ure not all predators. Therefore, they have followed different evolu- tionary pathways and sometimes metamorphosis takes place, with larvac and nymphs (similar in these cases to those of holometabolic insects) or with ‘survival’ instars which enable them to dis- perse. This evolution of clutch or juvenile care by the mother does not indicate phylogenetic relations in the different orders, because it is a generul phenomenon within the animal world and can appear independently in different groups. LITERATURE CITED ANDRE, H.M. 1989. The concept of stase, Pp. 3-14. In: H.M, André and J.C. 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Zur Entwicklungsgechichte von Prosoma Thelypionus caudatus L. (Pedipalpa}. 2. Teil. Die Entwicklung der Mundwerkzeuge- Beinhiifien und Stema. Zoologische Jahrbticher, Anatomie und Ontogenie 70: 169-197. LAWRENCE, R.F. 1947. Some observations on the eggs and newly hatched embryos of Selpuga hos- tilis White (Arachnida). Proceedings of the Zoological Society of Landon J 17: 429-434. LEGENDRE, R. 1958. Contribution @ létude du développement embryonnaire des Araignées. Bulletin de la Société Zoologique de France 83: 60-75. MILLOT, J. 1949, Ordre des Amblypyges. 563-588. In: P.P. Grasse (ed.). ‘Traité de Zoologie’. Vol 6. Masson: Paris. MUMA, MLH. 1966. The life cycle of Eremobatey duwrangenus (Arachnida: Solpugida). Flonda En- tomologist 49; 233-242_ NAISSE. 11959. Nevrosécrétion et glandes endocrines chez les Opilions. Archives de Biologie 70; 217- 264. PAVLOVSRY, E.N. 1924. Studies on ihe organization and development of scorpios. 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Die Primiirlarve der Walzenspin- nen Gyllipus cf. cypriotica Lawrence (Arachnida, Solifugae, Karschiidac), Mitteilungen der Schweizerischen Entomologischen Gesellschaft $5; 93-95, VACHON, M. 1938. Recherches anatomiques et biologiques sur la reproduction et le développement des Pseudoscorpions. Thése Doct. Etat, Paris: 1-207; Annales des Sciences Naturel- les, Zoologie, série (1: 1-207. 1940. Sur la systématique des scorpions. Mémoires du Muséum Nationa) d'Histoire Naturelle de Paris 2: 241-260. 1958a. La larve de Galeodes arabs C.L. K. (Arach- nide, Solifuge), Comptes Rendus de I’ Académie des Sciences, Paris 246: 477- 480. 1958b. Contribution a l'étude du développement post-embryonnaire des Araignées. }@° note; généralités et nomenclature des stades. Bulletin de la Société Zoologique de France $2, 1957 (1958); 337-354, WEYGOLDT, P. 1969. ‘The Biology of Pseudoscorpions’. (Harvard University Press: Cambridge, Mass. ). 1970. Lebenzyklus und postembryonische Entwick- lung der Geisselspinne Tarantula mar- ginemaculata C.L. Koch (Chelicerata, Amblypygi) im Laboratorium, Zeitschrift fiir Morphologie der Tiere 67; 58-85, 1975. Untersuchungen zur Embryologie und Mor- phologie der Geisselspinne Tarantula mar- ginemaculata C.L. Koch (Arachnida. Amblypygi, Tarantulidae). Zoomorphologie 82: 137-199. YOSHIKURA, M. 1965. Postembryonie development ofa whip scorpion, Typopeltis stimpyonti (Wood). Kumamoto Journal of Science, Senes B Biology 7: 21-50. 1975, Comparative embryology and phylogeny of Arachnida. Kumamoto Journal of Science, Series. B Biology 12: 71-142. YSNEL, F.1992. Impact trophique et valeur bioin- dicatrice d'une population d’ Araignées: Exemple d'une espéce a toile géométrique Larinioides cor- nutus{ Acaneidae), Thése Université Rennes 1.217 PP. COURTSHIP, MATING AND POST-OVIPOSITION BEHAVIOUR OF HYPOCHILUS POCOCKI PLATNICK (ARANEAE, HYPOCHILIDAB) K. M. CATLEY Catley, K.M. 1993 11 11: Courtship, mating and post-oviposition behaviour of Hypochilus pococki Platnick (Araneac, Hypochilidae). Memoirs of the Queensland Museum 33 (2): 469-474. Brisbane, ISSN 0079-8835. Courtship and mating in Aypochilas pecocki Platnick is described for the first lime for any member of the superfamily Hypochiloidea. Five phases of male behaviour are recognised, pre-courtship, non-contact courtship, contact courtship, copulation and posi-copulatory behaviour. Chemotactic Stimulation seems to be the prime releaser of male courtship behaviour which involves web-tugging, mutual leg-stroking and female guarding. Post- aviposifion behaviour is described and the role of a previously undescribed sheet web, constructed by females after oviposition as well as early instar spiderlings, is discussed in terms of its phylogenetic implications DAypachilus, courtship, phylogenetics, sexual selec- tion, web construction. K.M. Catley, Department of Biology, Western Carolina Universiry, Cullawhee, North Carolina 28723, USA; Preseni address: Department of Entomology, Comstock Hall. Cornell University, lthaca, New York 14853-0999, USA, 13 Oclober, 1992. The significance of undertaking ethological studies of spiders in the family Hypochilidae stems from the phylogenetic position of the fami- ly as a relic taxon al the base of the Infraorder Araneomorphae (Platnick, 1977; Forster et al., 1987), Diagnosis of behavioural units that are used in such processes as web construction (Cod- dington, 1986) and courtship (Platnick, 1971; Helversen, 1976; Coyle and O'Shields, 1990) may prove useful in future phylogenetic analysis. This paper describes the courtship and mating behaviour of Hypochilus pococki in the laboratory and attempts to recognise potentially informative behavioural sequences. Egg sac con- struction is also described and attention drawn to a previously undescribed silk construct, a ‘veil web’ built by post egg-laying females as well as early instar spiderlings, Apart from one mcom- plete observation by Fergusson (1972) of mating in Hypachilus thorelli Hoffman (=Hypochilus poceecki), this is the first detailed description of reproductive behaviour for any member of the superfamily Hypochiloidea. The genus Hypechilus comprises tive species confined to the Southern Appalachian highlands ot eastern North America, \wo species from central and northern California and one from central Colorado, Two additional species, one from New Mexico and the other from the San Bernardino Mountains of southern California will soon be described (Catley in prep.). These haplogyne cribellate spiders build characteristic ‘lampshade’ webs on rock surfaces offen close lo running water. All species appear to be allopatric and exhibit an interesting pattern of disjunct en- demism (Catley, 1991; Huff and Coyle, 1992). Males moult to maturity later than females, typt- cally appearing in carly August. They move ex- tensively (presumably in search of females) and do not associate with penultimate females, sug- gesting that there is no first male sperm precedence (Eberhard ef al, in press). MATERIALS AND METHODS Despite extensive day and night observation during 1990 and 199], no courtship or mating behaviour was observed in the field. Hypochilus can be very difficult to maintain in the laboratory; they are aifected adversely by changes in humidity and only occasionally can they be per- suaded to construct a web, making feeding problernatical, Following several unsuccessful attempts to establish a mature female in the laboratory, a single specimen collected in July 1990 from Wolf Creek watershed, Cullowhee, Jackson County NC, established a web in a 50x30cm glass tank. The tank was furnished with a sloping wooden framework (45°angle) covered with sandpaper to simulate an overhanging rock ledge. The floor was covered with vermiculite to a depth of 5cm and was kept very moist. After the female attacked and killed the first male introduced into the arena, she was allowed to feed for a period of one week. The second male was introduced on August 28 1990 and a total of 7 hours 47 mins of male/female encounters were filmed using a Panasonic WV-D5000 video re- 470 MEMOIRS OF THE QUEENSLAND MUSEUM larnpatede contacts female web 2. 5 t manipulates web with Fe pedipalps and legs ° no response e : Oy E A grooms legs and [ ‘pobbing’ | pedipalps 9 palpal gesticulation x web-tugging 2 < 2) = | ° é ’ 3 € So retreats : [attacks é leaves web but tugging on lampshade no attack, breaks down wall approachs male 2 a ia ee £ mutual Fy leg stroking o 8 ae ee : ; , = 2 3 palpal insertions Qa ° o returns to lampshade ae Pie c takes up ‘guarding’ 2 position pac a2 9 o FIG. 1. Sequence of courtship and mating behaviour in Hypochilus pococki formulated from encounters in the laboratory involving two males and a single female (see text for explanation). COURTSHIP IN HYPOCHILUS POCOCKI corder fitted with a Micro-Nikker 55mmclose-up lens. Sessions were annotated by verbal com- ments recorded through the audio channel of the video camera, Data analysis was achieved using soa motion and freeze frame functions of a RESULTS The description of courtship and mating presented here is a composite derived from laboratory observations of only two males and a single female and therefore may not be repre- sentative, Male courtship behaviour can be divided into five distinct phases: pre-courtship, non-contact courtship, contact courtship, copulation and post- copulation (Fig. 1). The following behavioural units were diagnosed. Mace BEHAVIOURAL Units PRE-COURTSHIP Leg and pedipalpal grooming, Within a few minutes of a male being introduced into the arena, the legs and pedipalps were used to manipulate female silk. A web constructed by the same female but which had been abandoned for several weeks elicited the same response. Rubbing the tarsi and metatarsi of legs 1, 2 and 3 together, as well as drawing them and the pedipalps between the open chelicerae (and presumably the endites) occurred immediately after the first and sub- sequent encounters with the female web. The pedipalps were rubbed vigorously across the silk for extensive periods, this was followed either by drawing them through the mouthparts, as described above, or by rapid pedipalpal gesticuls- tions. Babbing. Flexing of the legs resulted in the whole body moving up and down relative to the substrate. Bobbing is often interspersed between sessions of leg and pedipalp grooming. NON-CONTACT COURTSHIP Web-tugging. The male pulled on the cribellate lampshade web of the female with his first pair of legs. Such actions, repeated in bouts lasting 3-7 seconds interspersed with periods of inactivily lasting from. 5 sees. to several mins., can result in the side wall of the lampshade being partially destroyed. CONTACT COURTSHIP Leg-stroking. The female eveniually Iett the 47) web as a result of male tugging and approached the male, waving her front pair of legs. The male held his ground (unlike previous female ap- proaches which appeared aggressive and from which the male quickly withdrew). A long ses- sion of mutual leg-stroking followed, involving mainly legs one and two. The male maintained a constant, very rapid stroking of the female's legs (mainly metatarsi and tibiae) and body as she appeared to become progressively more catalep- tic, and eventually assumed the acceptance pos- ture. This stroking session lasted for 3 mins, 12 secs—more than twice the period of copulation itself. COPULATION Palpal insertions. Following mutual leg-strok- ing the female oriented her abdomen at 45° to the substrate and adopted a semi-cataleptic accep- tance posture. The male faced the female and advanced, with pedipalps fully extended, to a position where his dorsal cephalothorax was ad- jacent to the fernale’s stermum (Fig. 2). Tt was not entirely clear whether or not the sale tapped on the female’s genital area with his palps prior to insertion as described for some araneids (Robin- son and Robinson, 1980), Such apparent tapping may simply be attempts to locate the opening to the bursa copulatnx- The palps were inserted alternately, the right followed by the left, each insertion lasted 3-10 seconds with the whole insertion sequence lasting I min. 22 secs. To achieve insertion from this position requires that the palpal organ be twisted through 90° at the same time as the pedipalp ts straightened. The copulatory phase ended abrupt- ly when the female broke away from the male, who was immediately pursued some distance from the web. At no time during courtship or mating was the male observed to lay down silk POST-CQPULATION ‘Guarding’ posture. After copulation, the male, after a brief period of palpal grooming, took upa characteristic position close to the female, often touching her. His legs were extended parallel to the substrate, with the first three pair directed anteriorly, and the fourth pair directed posteriar- ly. The first pair of legs were held in such a position such that the femora were at 30° to the longitudinal axis of the prosoma, while the remaining podites tended to converge distally over the female. This seems to be a characteristic position seen often in the field. It was maintained a a MEMOIRS OF THE QUEENSLAND MUSEUM PIG, 2. Mating position of Hypechilus pococki (for the sake of clarity not all male appendages are illustrated). for 2.5 hours after which the female attacked and badly injured the male. FEMALE BEHAVIOURAL UNits NON-CONTACT Attack. The female failed for Jong periods to show any response to the male's web-tugging but did eventually respond by rushing out of the lampshade and pursuing him. Three attacks ap- peared in earnest, with the male withdrawing rapidly. The fourth response was instigated more slowly (with reduced speed and vigour); this change im ‘intent’ appeared to be sensed by the male, who did not retreat. This encounter led directly to contact courtship and copulation (Fig. 2). CONTACT COURTSHIP Leg stroking, See male behaviour. COPULATION Acceptance posture, A semi-cataleptic position with the abdomen held at 45° to the substrate (Fig. 2) occurring after contact courtship (extensive leg stroking) with the male. POST-COPULATION Ege laying ethology. Twenty days after copula- tion, the female laid eggs and constructed an egg-sac. First a saucer-shaped disc of pink silk was laid down onto which the eggs were deposited. This was then closed up to form a flattened sphere. The pink colour of the silk has been corroborated by several observations in the field, however, when the egg-sac is ready to be covered in cryptic material its colour is off-white. A second egg-sac was produced on October 4, followed by a nich smaller egg-sac on October 17, and the final egg-sac was constructed on November 6, Each was suspended from the framelines of the web while particles were incor- porated in the outer layer of the egg-sac. This involved the spider descending to the substrate and carrying pieces of vermiculite back to the web in her chelicerae (in the field egg cases are covered with particles of moss or lichen (Fergus- son, 1972; pers. obs.). Two eyg-sacs were ‘screened in’ by a particular type of sheet web not previously described for Hypochilus, Observations from the field show that a similar ‘veil web’ is also constructed by early instar spiderlings (Catley, 1991). The silk is of very different appearance from either framework or cribellate silk and appears as a dense, finely woven sheet. Its purpose, either as a vertical ‘veil’ in front of egg-sacs (typically those suspended in a fissure in the rock), or asa barrier underneath which a number of very early instar spiderlings build their regular prey catch- ing lampshade webs, may be protective, DISCUSSION The function of courtship in spiders may be most simply expressed as: alerting the female to the presence of the male, the possible suppression of female predatory behaviour and stimulation of the female to accept copulation. Variations on this basic theme have been voiced by several authors including Bristowe (1958), Crane (1949) and Platnick (1971); most expand the concept to include elements of species. specific recognition, advertisement of sexual availability and the functioning of a releaser system, Other com- ponents which may also be important are male behavioural elements designed to ensure his post- copulation survival. COURTSHIP IN HYPOCHILUS POCOCK! Accounts of courtship and mating in other more primitive spider taxa are scant, but include infor- mation on the Mesothelae: Liphistiidae, Hep- tathela (Haupt, 1977}; Mygalomorphae: Nemesndae (Buchli, 1962); Atypidae (Clark, 1969); Dipluridae (Coyle and O'Shields, 1990), Whereas behavioural observations for spiders in the Araneoclada are available from Bristowe (194], 1958) various fumilies, Crane (1949) for salticids, and Robinson and Robinson (1978, 1980) for araneids, this account of courtship and mating in Hypochilas is the first 10 be published for any lower (nonAraneoclada) araneomorph spider The courtship and mating repertoire of Hypechilus ts relatively underived and given the families’ phylogenetic position the behavioural units which comprise it may be hypothesised to represent the plesiomorphic condition of arineomorph reproductive behaviour in general. Given a larger data base within the Araneomor- phae, comparison of behavioural characters will allow correct polarity decisions to be made and the resulting data set, combining beth mor- phological and ethological characters. should provide a more stringent test of phylogeny. Leg and pedipalpal grooming behaviours per- formed by the male upon contact with the female web may be indicative of the occurrence of female pheromone on the web. Such pre-conlact encounters were necessary to release web-tug- ging behaviour in these observations (n=4) and is consistent with Platnick's (1971) hypothesis that chemotactic stimuli are prime releases of male courtship behaviour in haplogyne spiders. It has been suggested that the Jonger anterior legs of male Aypochilus confer superior mobility when locating females (Fergusson, 1972; Eberhard ef al in press). However, such pronounced sexual dimorphism may have had its origin in courtship behaviour. The extreme length of the first legs, by maximising the distance between male and female during Web-tugging, should increase the mule's chance of surviving female altacks, Such interactions may also provide an opportunity for sexual selection by female choice to occur (Eber- hard, 1985), ihe female testing male ‘fitness’ by repeated attacks. Contact courtship was initiated when the female eventually left the lampshade and ap- proached the male. Such behaviour may not how- ever he typical. Fergusson (1972) reported that in the one encounter he observed ihe male scrambled into the lampshade with the female. The long period of mutual leg-streking may play ATA a role in placating the female, resulting in her adopting the acceptance posture. It may well he homologous with the ‘leg fencing’ behaviour seen in some diplund spiders (Coyle and Q*- Shields, 1990). Copulation was achieved in the mating pasition (Fig. 2: position 1 of Kaston, 1981). Alternate palpal insertions, as observed in Hypochilus, should be considered plesiomorphic when en- countered in other arancomorph spiders (using Hypochilus as an outgroup) and as apomorphic when palps are inserted simultaneously. Sirnul- taneous palpul insertion has been documented in the following families, Dysderidac, Segestriidac, Oonopidac, Scytadidae and Pholcidae (Bristowe, 1958) but appears not, as Bristowe concluded, to be plesiomorphic for the Arancoclada. Simul- laneous insertion may well prove to be a synapomorphy for the higher haplogynes, Dys- deroidca plus ‘Scytocdids’ (Coddington and Levi. 1991), The post-copulatory position taken up by the male is believed to represent a guarding posture. HAypochilus pococki males have been shown con- clusively not to associate with penultimate females (Eberhard e? al. in press). Hence, that the numerous occasions when males were found in this position in the field, suggest that they repre- sent in fact, post-mating situations, and that the male was most likely guarding the female and thus his chance of paternity. The implications of the ‘veil’ web produced by the female following egg-sac construction re- quire further comment. Hypochilus ege-sacs are superbly cryptic and mast are not concealed by such a ‘veil’ web (Shear, 1969; Fergusson, 1972; Catley, 1991). The behaviour of some females in concealing egg-saes might have primitively rep- resented a selective udvuntage from vertebrate or hymenopteran predation. Accepting the cladistic hypothesis of Forster et al. (1987) on the relationships of the Hypochiloidea and Austrochiloidea, data on sheet web construction in these taxa suggests that the lampshade web of Hypachilus is autapomor- phic. Ectatasticta davidi (Simon), the sister taxon of Hypockilus, constructs a sheet web (Li and Zhu, 1984) as do all known members of Austrochilidse (Forster et al., 1987), Ontogenetic evidence, based on the observation that very carly instar spidertings alsu construct a sheet web (Cat- ley, 1991), also supports this hypothesis and lends some weight tothe suggestion that the plesiomet- phic web construct of araneamorph spiders was the sheet web, 474 ACKNOWLEDGEMENTS Grateful thanks are due to Dr. Frederick Coyle for the loan of video recording equipment, Rudolf Meier for help with translations and Dr. William Shear for his useful comments on an early draft of the manuscript. I should like to acknowledge financial support from the Organising Committee of the XII International Congress of Arachnol- ogy, the Graduate School of Cornell University and the Grace Griswold Fund which allowed me to attend this Congress. LITERATURE CITED BRISTOWE, W.S. 1941. The Comity of Spiders, vol. II. (Ray Society: London). 1958. The World of Spiders. (Collins: London). BUCHLI, H. 1962. Note préliminaire sur l’accouplement des araignées mygalomorphes Nemesia caementaria, Nemesia dubia et Pachylomerus piceus. Vie et Milieu 13: 167-178. CATLEY, K.M. 1991. The phylogenetic relationships of the species of the lampshade spider genus Hypochilus (Araneae, Hypochilidae), (Un- published Masters thesis, Western Carolina University). CLARK, D. J. 1969. Notes on the biology of Atypus affinis Eichwald. Bulletin of the British Arach- nological Society 1: 36-39. CODDINGTON, J. A, 1986. The monophyletic origin of the orb-web. Pp. 319-363. In Shear, W. A. (ed). ‘Spiders. Webs, behavior, and evolution’. (Stan- ford University Press: Stanford, California). CODDINGTON, J. A. & LEVI, H.W. 1991. Sys- tematics and evolution of spiders (Araneae). An- nual Review of Ecology and Systematics 22: 565-92. COYLE, F. A. & O’SHIELDS, T. C. 1990. Courtship and mating behavior of Thelechoris karschi (Araneae, Dipluridae), an African funnel web spider. Journal of Arachnology 18: 281-296. CRANE, J. 1949. Comparative biology of salticid spiders at Rancho Grande, Venezuela. PartIV. An analysis of display. Zoologica 34: 159-214. EBERHARD, W. G. 1985. Sexual selection and animal genitalia. (Harvard University Press:Cambridge). EBERHARD, W. G., GUZMAN-GOMEZ, S. & CAT- MEMOIRS OF THE QUEENSLAND MUSEUM LEY, K. M. (in press). Correlation between sper- mathecal morphology and mating systems in spiders. Biological Journal of the Linnean Society. FERGUSSON, I. C, 1972. Natural history of the spider Hypochilus thorelli Marx (Hypochilidae). Psyche 79: 179-199, FORSTER, R.R., PLATNICK, N.I. & GRAY, MLR. 1987. A review of the spider superfamilies Hypochiloidea and Austochiloidea (Araneae, Araneomorphae). Bulletin of the American Museum of Natural History 185: 1-116. HAUPT, J. 1977 Preliminary report on the mating be- haviour of the primitive spider Heptathela kimurai (Kishida) (Araneae, Liphistiomorphae). Zeitschrift fiir Naturforschung 32: 312-314. HELVERSEN, O. VON 1976. Gedanken zur Evolution der Paarungsstellung bei den Spinnen (Arachnida, Araneae), Entomologica Germanica 3: 13-28. HUFF, R. P. & COYLE, F. A. 1992. Systematics of Hypochilus sheari and Hypochilus coylei, two southern Appalachian lampshade spiders (Araneae, Hypochilidae). Journal of Arachnology 20: 40-46. KASTON, B.J. 1981. Spiders of Connecticut. State Geological and Natural History Survey of Con- necticut. Department of Environmental Protec- tion, Bulletin 70. LI, ZHONSHAN & ZHU, CHAUNDIAN, 1984. Ec- tatosticta davidi (Simon, 1888) of China (Araneae: Hypochilidae). Journal of the Bethune Medical University 10(5): 510 (in Chinese). PLATNICK, N. I. 1971. The evolution of courtship behaviour in spiders. Bulletin of the British Arach- nological Society 2(3): 40-47. 1977. The hypochiloid spiders: a cladistic analysis with notes on the Atypoidea (Arachnida, Araneae). American Museum Novitates 2627: 1-23. ROBINSON, M.H. & ROBINSON, B. 1978. The evolution of courtship systems in tropical araneid spiders. Symposia of the Zoological Society of London 42: 17-29. 1980. Comparative studies of the courtship and mating behavior of tropical araneid spiders. Pacific Insects Monograph 36: 1-218 SHEAR, W. A. 1969. Observations on the predatory behavior of the spider Hypochilus gertschi Hof- fman (Hypochilidae). Psyche 76: 407-417. EFFECTS OF SAMPLING METHOD ON COMPOSITION OF A TASMANIAN COASTAL HEATHLAND SPIDER ASSEMBLAGE TRACEY B. CHURCHILL Chorchill, T.B. 1993 11 11: Effects of sampling method on composition of a Tasmanian coastal heathland spider assemblage. Memoirs of the Queensland Museum 33(2;): 475-481, Brisbane. ISSN 0079-8835. The composition of a spider community in coastal heathlands of north-east Tasmunia was derived from a 16 month survey using pitfall traps, sweep net and visual search sampling methods incorporated into a replicated, standardised sampling program, This interpretation of composition ts shown to rely on the relative efficiency of the three collecting methods to sample the taxa present. Since mature spiders are required to confirm species identity, the differential selection of age and sex classes by the methods is illustrated. Whilst pitfall traps catch a greater number of taxa (at all taxonomic levels) and adult spiders, certain taxa are not or barely represented by this widely used technique. The subjective nature of the visual search method allows for the potential to target mature spiders. Limits of the sampling methods are emphasised in response to a growing dependence on survey data for the assessinent of biodiversity QAraneae, methodology, biodiversity, heathland, invertebrates, community. Tracey B. Churchill, Division of Environmental Science. Griffith University, Natlan, Queensland 41/7, Australia; 6 Navember, 1992. Surveys of spider communities in Australia have primarily been motivated by specific taxonomic interests in this relatively unknown faunal group, Whilst this has lead to invaluable improvements in taxonomy, such collections are increasingly being utilised to extract data for the making of critical conservation management decisions, It is therefore necessary that further consideration be given to the factors that can affect the interpretation of survey results. The primary factor that limits the comparability of data from different locations or times is the method used to sample spiders, Different methods can preferentially sample certain microhabitats and/or particular taxa (Merrett and Snazell, 1983). For example, the commonly used pitfall trap selects ground active species (Duffey, 1974: Merrett and Snazell, 1983; Lowrie. 1985) and the use of this method alone can produce species lists that under-represent more sedentary or foliage inhabiting members of the community. The effectiveness of different sampling techni- ques can be influenced by behavioural differen- ces between not only taxa, but also age or sex classes of a given species. For example, males of many species are more readily captured by pitfall traps than females due to their active search for a mate (Merrett, 1967, 1968), which may represent ground activity in an otherwise foliage dwelling taxa. Since mature specimens are usually re- quired to identify species or genera, the ability to catch adults will effect the accuracy of a species list. By adopting a suite of collecting techniques to target spiders both on the ground and in vegeta- lion, the chances of sampling all taxa present are increased and thus data more useful for corn: munily studies are collected (Uetz and Unzicker, 1976). Accordingly, acombination of pitfall trap, sweep netand visual search methods was selected fora 16 month survey of spiders in the north-east coastal comer of Tasmania. The area is largely developed as sheep and cattle grazing properties, although to the seaward side of the remaining coastal Eucalyptus and Casuarina forests is often a margin of heathland dominated by members of the Proteaceae, Casuarinaceae, Epacridaceac, Papilionoideae and Xanthorrhocaceae. An in- creasing impact of recreational and residential development threatens the remaining heathland (Kirkpatrick, 1977). In this paper, the composi- lion of spiders in the heathland community is inferred by the list of spider taxa collected over the survey period. The relative efficiency of the three sampling methods in capturing dominant taxa is then compared to illustrate how the choice of method can influence the final interpretation of community composition or species richness. MATERIALS AND METHODS Spiders were collected using pitfall traps, sweep net and by visual searching, each of which 476 was standardised for effort and replicated. At monthly intervals from October 1986 to January 1988, sampling was carried out during a one week field trip. Two replicate 90m* sites were selected at each of two study areas, Waterhouse Point and Eddystone Point. Within each site there were nine 18m* plots placed 18m apart in three rows of three. This allowed for three replicate plots per sampling method, allocated initially at random. For the relevant plot the following sampling routine was employed: a) Nine pitfall traps were set 4.5m apart in a 3 x 3 matrix using 9cm diameter traps; b) one sweep sample of 50 sweeps was taken using a 28cm diameter net in a 12 x 3 m area and c) visual searching for 30 minutes was made over a 3 x 3m area, Spiders were preserved in 70% alcohol, identified to species where pos- sible, and lodged with the Queen Victoria Museum, Launceston, Tasmania. The three sampling methods were considered to be complementary in their selection of taxa occupying different strata. Pitfall traps sample spiders mobile on the ground, in contrast to sweep netting which targets spiders in the foliage. Visual searching can reveal spiders in any MEMOIRS OF THE QUEENSLAND MUSEUM microhabitat, but a bias was shown towards those secured within web retreats, as such groups may not be amenable to capture by the previous two methods. RESULTS AND DISCUSSION Composition A total of 8,625 spiders were collected using all three methods over 16 months, and these spiders comprised 130 species of the Araneomorphae in 97 genera and 34 families (see Table 1). Names could not be allocated to 26% of genera and 92% of species, indicating further that many Australian groups need taxonomic revision (Davies, 1985; Raven, 1988), The most diverse families in terms of the number of species were the Salticidae (14 spp.) and Gnaphosidae (11), followed by the Theridiidae (9), Zodartidae (9), Thomisidae (8) and Araneidae (8). The four most abundant species were, in decreasing order Diaea sp. (5.8%), Badumna vandiemani (5.3%). Odo sp. (4.3%), Hestimodema sp. (4.1%). The number of spiders falling into pitfall traps depends on their activity (Mitchell, 1963; Lycosidae Zoridae Amaurobiidae Gnaphosidae Zodariidae Thomisidae Prodidomidae Salticidae Theridiidae Linyphiidae Micropholcommatidae Clubionidae 600 q | 1200 1800 2400 Number of individuals FIG. 1. Number of individuals (shaded bars) and adults (black bars) for the twelve dominant spider families. SAMPLING METHODS AND TASMANIAN SPIDERS Amaurobiidae Genus A sp.1 * Genus A sp.2 * Genus B sp. Genus C sp. Genus D sp. Amphinectidae Amphinecta milvinus (Simon, 1903) Mamoea sp. Araneidae Cyclosa sp. Eriophora biapicata (Koch, 1871) Gasteracantha minax Thorell, 1859 Genus E sp. Genus F sp. Genus G sp. Genus H sp. Genus I sp. Clubionidae Cheiracanthium sp. Clubiona sp. 1 Clubiona sp. 2 Clubiona sp. 3 Genus J sp. Corinnidae Asadipus sp. Castianeira sp. Supunna sp. Cyatholipidae Hanea sp Marilda sp. Desidae Austmusia sp. Badumna vandiemani Gray, 1983 * Forsterina sp. Tuakana sp. Dictynidae Callevophthalmus sp.1 Callevophthalmus sp.2 Gnaphosidae Anzacia sp.) * Anzacia sp.2 * Eilica sp. * Megamyrmaekion sp. Micaria sp. Trachycosmus sp. * Zelotes sp.1 Zelotes sp.2 Zelotes sp.3 Genus K sp. Genus L sp. Hadrotarsidae Hadrotarsus sp.1 Hadrotarsus sp.2 Genus M sp. Hahniidae Neoaviola sp. Heteropodidae Neosparassus sp. Linyphiidae Laetesia sp.1 * Laetesia sp.2 Laetesia sp.3 Laetesia sp.4 Genus N sp. Genus O sp. Lycosidae Artoria sp.1 * Artoria sp.2 * Artoria sp.3 Artoria sp.4 * Artoria spp. Lycosa funesta (Koch, 1849) Lycosa speciosa (Koch, 1879) Lycosa sp. Micropholcommatidae Micropholcomma sp.1 Micropholcomma sp.2 Textricella sp.1 Textricella sp.2 * Textricella sp.3 Mimetidae Australomimetus sp. Miturgidae Miturga sp.1 Miturga sp.2 Uliodon velox (Hickman, 1930) Uliodon sp. Mysmenidae Genus P sp. Nicodamidae Nicodamus melanozanthus (Urquhart, 1893) Oecobiidae Oecobius annulipes Lucas, 1846 Oonopidae Orchestina sp. Genus Q sp. Oxyopidae Genus R sp. Pararchaeidae Pararchaea sp. Pisauridae Dolomedes sp. Prodidomidae Molycria sp. * Salticidae Lycidas sp. Maratus sp. * Opisthoncus sp. Pseudosynagelides sp. Servaea sp. Genus S sp.1 Genus § sp.2 Genus S§ sp.3 Genus § sp.4 Genus T sp. Genus U sp. Genus V sp. Genus W sp. Genus X sp. Stiphidiidae Biaimi sp. Corasoides australis Butler, 1929 Stiphidion facetum Simon, 1902 Tetragnathidae Deliochus sp. Phonognatha sp. Tetragnatha sp. Theridiidae Achaearanea sp. Dipoena sp. Episinus sp. Euryopis sp. 477 Phoroncidia trituberculata (Hickman, 1951) Steatoda sp.1 Steatoda sp.2 Steatoda livens (Simon, 1895) Theridion sp. * Thomisidae Cymbacha sp. *. Diaea sp. * Sidymella sp.1 Sidymella sp.2 Sidymella sp.3 Sidymella sp.4 Sidymella longipes (Koch, 1874) Stephanopis sp. Toxopidae Laestrygones setosa Hickman, 1969 Trochanteriidae Corimaethes sp. Zodariidae Asteron sp. * Asleron “reticulatum”™ “Australatica” sp. Habronestes sp.1 Habronestes sp,2 Habronestes “bradleyi” Neostorena sp.1 Neostorena sp.2 Nostera sp. Zoridae Argoctenus sp. Hestimodema sp. * Odo sp. * Thasyraea sp. TABLE ]. List of spiders collected from Tasmanian coastal heathlands. Asterisk indicates the 20 most abundant species. 478 Greenslade, 1964; Uetz and Unzicker, 1976; Merrett, 1983) and not necessarily on actual abundance in the community (Merrett, 1967; Merrett and Snazell, 1983). Individuals active on foliage presumably experience a higher prob- ability of being knocked into a sweep net and for the visual search method the chance of noticing spiders would be increased by their activity (Cur- tis, 1980). Therefore it is stressed that references to abundance in this paper relate to numbers caught and not population size. With respect to the number of individuals, the collections were dominated by the Lycosidae (26% of the total), Zoridae (10%), Thomisidae (9%) and Zodariidae (9%) (Fig. 1). The families Salticidae, Amaurobiidae, Desidae and Gnaphosidae then account for the next 22%. With the exception of the zodariids and zorids, these families are amongst the largest in Australia (Raven, 1988). The Araneidae, which are other- wise the most abundant Australian spider family (Raven, 1988), comprised only a minor com- ponent of this collection (1.4%). The dominance hierarchy (Fig. 1) is determined by the number of adults in each family. However, as it is not standardised as to whether the whole data set (including immatures) or only the adult data are used to describe patterns of family dominance in a given community, a comparison is made to both (Fig. 1). The interpretation of relative abundance of families is affected by which category is used. Given that only adult data are useful for comparisons at the generic or species level, adult data seem the better choice for assessments of biodiversity. EFFECTS OF SAMPLING METHOD ON COMPOSITION Pitfall traps collected the most individuals (6212), followed by visual searching (1900) and sweep netting (513). However, as the sampling effort of pitfall traps far exceeds that of sweep netting and visual searching, comparisons of taxa between methods are made relative to the total of each method. Due to a reliance on acquiring mature spiders from surveys to confirm species and generic level identifications, Fig. 2 presents the differential distribution of age and sex classes for each sam- pling method. Pitfall traps clearly caught the greatest percentage of males (35%) and visual searching, the least (3%). Females are also col- lected more by pitfall traps, although the dif- ference between methods is not as distinct. Accordingly, the percentage of immature spiders increases from pitfall traps (46%), through sweep MEMOIRS OF THE QUEENSLAND MUSEUM f@ FEMALES m MALES 70 — & SUBADULT FEMALES i) PENULTIMATE MALES JUVENILES 60 Ss 50 — l T i 40 30 AA = 20 % Individuals per sampling method 10 PITFALL TRAP SWEEP NET VISUAL SEARCH FIG. 2. Percentage of individuals in each sampling method for the different age and sex classes. net (75%) to visual search (84%) methods. From these results pitfall traps seem to be the most efficient at selecting mature spiders from the coastal heathland community. The total number of families, genera, and species can be compared to that collected by each sampling method (Table 2). At each taxonomic level, pitfall traps sample the most taxa (between 87-94% of the total), followed by visual search- ing (41-66%) and sweep netting (25-41%). It is relevant to point out that the results presented here were derived over a 16 month survey period. The likelihood of recording certain taxa using a given sampling method for typically shorter sur- vey periods depends on the relative ease with which they are collected by that method (it also depends on the temporal abundance of taxa, to be discussed elsewhere). The percentage of adult a =e 4 23 Species 130 TABLE 2. The number of taxa in total, and for each sampling method at three taxonomic levels, SAMPLING METHODS AND TASMANIAN SPIDERS 479 Lycosidae Zoridae Amaurobiidae Gnaphosidae Zodariidae Thomisidae Prodidomidae Salticidae Theridiidae Linyphiidae Micropholcommatidae Clubionidae @ Visual search (n=303) 1 Sweep net (n=130) Pitfall trap (n=3315) | i) 10 20 30 40 50 % Adult total for each sampling method FIG. 3. Percentage of the adult spider total for each sampling method for the 12 dominant spider families. 90+ = — 7 — — g9 | Pitfall trap ° im | Sweep net : 2 Sun ol @ Visual search . | Be vo 2 60 — > 4a 63 50 —| Be E c oy = 40 —| fee ee a Bee EE Ss 30 —} ee i “| ee ee — Ee ~ 20 — Ke E 5 |e Co < 10 a ee fewest ae Z Ee Clubiona sp.1 Clubiona sp.2 Lycidas sp. Maratus sp. Servaea sp. Clubionidae Salticidae FIG. 4. Percentage of the adult spider total for each sampling method of Clubionidae and Salticidae. 480 spiders sampled by each method varies over the 12 dominant families (Fig. 3). Ground dwelling spiders such as gnaphosids or zodariids are ex- clusively caught by pitfall traps. Despite lycosids and zorids being sampled by all methods, there is a reduced chance that they would be represented by sweep net and visual searching over a shorter survey period. If only pitfall traps were used, the probability of representing the families Thomisidae or Salticidae is markedly reduced. Linyphiids, due to their habit of building low webs under the foliage are primarily amenable to capture by visual searching. Consequently, the results show that there is a greater probability of representing some families over others according to the method used. The number of species in each family are dis- tributed differently across sampling methods (Table 3). Whilst the ground dwelling spiders such as the gnaphosids and zorids have all their species falling into pitfall traps, other families have a pattern of species distribution across methods quite different to the distribution of in- dividuals. For example, thomisids may be best sampled using sweep netting and visual searching (Fig. 3). Yet, these methods inadequately sample all the thomisid species collected (Table 3). The contrast is explained by the two most abundant thomisids, Diaea sp. and Cymbacha sp. being collected mostly by sweep net and visual search methods. Further examples include all clubionid species being sampled by all three methods (com- pared to a very unequal distribution of in- dividuals) and a greater number of salticid species being sampled by pitfall traps (compared to this method catching the least number of sal- ticids). The number of individuals of the dominant Family Total sae wesee Visual Amaurobiidae 5 5 0 1 Clubionidae 5 3 3 3 Gnaphosidae 11 ll 0 0 Linyphiidae 6 6 1 6 7| ol 0 Micropholcommatidae 5 5 0 1 Prodidomidae 1 1 0 0 Salticidae 14 9 7 6 Theridiidae 9 6 2 Thomisidae 8 8 2 3 Zodariidae [9f 9[ of o TABLE 3. Number of species in total and for the three sampling methods for 12 dominant families. MEMOIRS OF THE QUEENSLAND MUSEUM species of clubionids and salticids illustrates that the differential selection of taxa by sampling method also operates at the species level (Fig. 4). Within the Clubionidae, despite the two species being collected by all three methods, Clubiona sp. 1 was almost exclusively sampled by pitfall traps, whereas Clubiona sp.2 was more often taken by a sweep net or visual searching. Similar- ly, the three dominant salticid species were preferentially sampled by the three different methods. Hence, if one sampling method was favoured over any other, especially for a shorter survey period, many species would be omitted from the final species list. IMPLICATIONS FOR THE FUTURE SURVEY OF SPIDER COMMUNITIES There is currently no spider sampling technique that is unbiased. The success of any method is usually related to certain aspects of spider be- haviour and therefore generally represents an in- complete range of taxa. Whilst this may be readily acknowledged by arachnologists, the limitations of a given method is not always clarified in the interpretation of community com- position. This is particularly important when non- arachnologists utilise the information as representative of the whole community. Despite the use of three sampling methods in this survey, the species list is not unbiased. In this study, sweep net and visual search methods were carried out during the day and may therefore not select nocturnally active taxa. Visual searching included looking at the ground, but effective sam- pling of leaf litter was not undertaken, and this micro-habitat can harbour distinctive families (Raven, 1988). The visual search method is also subjective in terms of where the search focus is directed. Attention was paid in this survey to sample spiders in positions (particularly in nests) that were not as vulnerable to the other two col- lecting methods. Where the objective of the sur- vey is to estimate taxonomic composition of the spider fauna, the efficiency of both the visual search and sweep net methods could be improved by avoiding the collection of distinctly immature spiders. Also, the equipment design can effect the num- ber of individuals and taxa caught (eg., for pitfall traps see Luff, 1975 and Curtis, 1980). Temporal factors can further influence which taxa are sus- ceptible to capture by a given method and as discussed by Abraham (1983), this can be related to seasonal migration of spiders between vegeta- SAMPLING METHODS AND TASMANIAN SPIDERS tive strata. To enhance the comparability of sur- vey data, there is therefore a need to standardise methodology, equipment design, sampling effort and timing. Yen and Butcher (1992) also make this plea in respect of terrestrial invertebrate sur- veys for the ultimate goal of conservation. Methodological limitations need to be taken into account during the final interpretation of tax- onomic lists for a more useful assessment of the fauna. These aspects are stressed in the light of a rapidly growing reliance on such data sets for conservation and management in Australia, and the need to critically assess invertebrate survey methods for estimating the loss of biodiversity worldwide (Coddington et al., 1991). ACKNOWLEDGEMENTS A survey of spiders of the north-east coastal heathland was supported by the Plomley Founda- tion at the Queen Victoria Museum, Launceston, Tasmania, who also funded curation of half of the spider collection. Specimens were identified and the curation completed with resources kindly pro- vided by the Arachnology section, Queensland Museum (Brisbane) and with taxonomic advice from Mark Harvey (Nicodamidae), Rudy Jocqué (Zodariidae), Rolly Mackay (Lycosidae), Robert Raven (all other taxa) and Marek Zabka (Sal- ticidae). Completion of the project has been poss- ible through an Australian Postgraduate Research Award at Griffith University, Brisbane. LITERATURE CITED ABRAHAM.]J. 1983. Spatial and temporal patterns ina sagebrush steppe spider community (Arachnida, Araneae). Journal of Arachnology 11: 31-50. CODDINGTON, J.A., GRISWOLD, C.E., DAVILA, D.S., PENARANDA, E. & LARCHER, S.F. 1991. Designing and testing sampling protocols to estimate biodiversity in tropical ecosystems. Pp. 44-60. In Dudley, E.C. (ed.) ‘The unity of evolu- tionary biology: proceedings of the fourth interna- tional congress of systematic and evolutionary biology’. (Dioscorides Press: Portland, Oregon). CURTIS, D. 1980. Pitfalls in spider community studies (Arachnida, Araneae). Journal of Arachnology 8: 271-280. DAVIES, V. TODD 1985. Araneomorphae (in part). Pp. 49-125. In Walton, D.W. (ed.) ‘Zoological 481 Catalogue of Australia. 3. Arachnida’. (Australian Government Printing Service: Canberra), DUFFEY, E. 1974. Comparative sampling methods for grassland spiders. Bulletin of the British Arach- nological Society 3: 34-37. GREENSLADE, P.J.M. 1964. Pitfall trapping as a method for studying populations of Carabidae (Coleoptera). Journal of Animal Ecology 33: 301- 310. KIRKPATRICK, J.B. 1977. ‘The Disappearing Heath’. (Tasmanian Conservation Trust Incorporated). LOWRIE, D.C. 1985. Preliminary survey of wandering spiders of a mixed coniferous forest. Journal of Arachnology 13: 97- 110. LUFF, M.L. 1975. Some features influencing the ef- ficiency of pitfall traps. Oecologia 19: 345-357 MERRETT, P. 1967. The phenology of spiders on heathland in Dorset: I. Families Atypidae, Dys- deridae, Gnaphosidae, Clubionidae, Thomisidae and Salticidae. Journal of Animal Ecology 36: 363-374. 1968. The phenology of spiders on heathland in Dorset: I. Families Lycosidae, Pisauridae, Agelenidae, Mimetidae, Theridiidae, Tetrag- nathidae, Argiopidae. Journal of Zoology (Lon- don) 156: 239-256 1983. Spiders collected by pitfall trapping and vacuum sampling in four stands of Dorset heath- land representing different growth phases of heather. Bulletin of the British Arachnological Society 6: 14-22 MERRETT, P. & SNAZELL, R. 1983. A comparison of pitfall trapping and vacuum sampling for as- sessing spider faunas on heathland at Ashdown Forest, south-east England. Bulletin of the British Arachnological Society 6: 1-13. MITCHELL, B. 1963. Ecology of two carabid beetles, Bembidion lampros (Herbst) and Trechus quad- ristriatus (Schrank) IL.Studies on populations of adults in the field with special reference to the technique of pitfall trapping. Journal of Animal Ecology 32: 377-392. RAVEN, R.J. 1988. The current status of Australian spider systematics. Pp. 37-48. In, Austin, A.D. and Heather, N.W. (eds) ‘Australian arachnology’. The Australian Entomological Society Miscel- laneous Publication No. 5. UETZ, G. E. & UNZICKER, J.D. 1976. Pitfall trapping in ecological studies of wandering spiders. Journal of Arachnology 3: 101-111. YEN, A.L. & BUTCHER, R.J. 1992. Practical conser- vation of non-marine invertebrates. Search 23: 103-105. A NEW SPIDER GENUS (ARANEAE: AMAUROBIOIDEA) FROM RAINFORESTS OF QUEENSLAND, AUSTRALIA VALERIE TODD DAVIES Davies, V. Todd. 1993 11 11: A new spider genus (Araneae: Amaurobioidea) from rain- forests of Queensland, Australia. Memoirs of the Queensland Museum 33(2): 483-489. Brisbane. ISSN 0079-8835. Malala gen.nov. is described and its relationships discussed; descriptions of two new species, Malala lubinae sp.nov. and Malala gallonae sp.nov. are given, including their spigot morphology. Malala is considered incertae sedis within the Amaurobioidea (sensu Leh- tinen).[Araneae, Amaurobioidea, new taxa, spigot morphology. Valerie Todd Davies, Queensland Museum, PO Box 3300, South Brisbane, Queensland 4101, Australia; 28 October, 1992. Many amaurobioid spiders in Australia no longer spin a web; they are usually vagrants either in litter or foliage and typically the forelegs have strong ventral spination. Two species of a tree- frequenting genus are described here. ABBREVIATIONS. Measurements: cephalo- thorax length (CL) and width (CW), abdomen length (AL) and width (AW). Eyes: anterior median (AME), anterior lateral (ALE), posterior median (PME), posterior lateral (PLE), anterior row (AR), posterior row (PR). Spinnerets: anterior (ALS), median (PMS), posterior (PLS). Collectors: R.J. Raven (RJR), N. Hall (NH), V.E. Davies (VED). On figures: ac aciniform spigot; als, anterior spinneret; at, anal tubercle; c, con- ductor; ep, protuberance on ¢ chelicera; cy, cylindrical spigot; e, embolus; fb, frontal bristle on 6 chelicera; fs, frontal spur on 3 chelicera; Map, major ampullate spigot; map, minor am- pullate spigot; ms, median sclerite; n, nubbin; pi, piriform spigot; pls, posterior spinneret; tf, tegular flange; to, tarsal organ. All specimens are lodged in the Queensland Museum. Malala gen. nov. TYPE SPECIES Malala lubinae, sp. nov. DIAGNOSIS Three-clawed, pale clubionine-like with long spinose legs. Eyes in almost straight rows; AME much smaller than other eyes. Narrow median sclerite above chelicerae. Chelicera with one or two long frontal bristles proximally; pointed frontal spur distally in 6. d palp without median apophysis; elaborate tibial apophysis with dorso- retrolateral element. FIGS 1-5. Malala lubinae. 1, 3, 2. 1, cephalothorax (lateral), 3, eyes and chelicerae (frontal), 2, 4,5, 3. 2, eyes and chelicerae (frontal), 4, chelicerae (ventral), 5, palp (ventral). DESCRIPTION Straw-coloured ecribellate spiders with little or no pattern on abdomen. Carapace rounded dor- sally, gradually declining in height behind fovea (Fig. 1). Anterior row of eyes straight, posterior row slightly recurved from above, procurved from front. Canoe-shaped tapetum in indirect eyes. Clypeus x 2 AME; narrow median sclerite above chelicerae (Figs 2,3). Sternum longer than wide, broadly truncate anteriorly, pointed posteriorly. Labium about as wide as long, a little more than half the length of the endite. Four-5 retromarginal cheliceral teeth; proximal ridge leading to 3-5 promarginal teeth, 2 small medial teeth between first and second marginals. Without long retrolateral filamentous setae at base of fang. Legs long (1243), trochanters un- notched. Coxae I longer than IV. Without plumose (ciliate) hairs on body or legs. Numerous strong ventral spines on tibiae and metatarsi I and 484 025 ee. AS OG Be FIGS 6-12. Malala spp. epigyna. 6-9, M. lubinae, ventral, ventral (cleared), posterior, dorsal. 10-12, M. gallonae, ventral, lateral, dorsal. II; metatarsi long, without preening combs; tarsi short. Trichobothria in a single row on metatarsi and tarsi. Bothria grooved, collariform (Fig. 14); tarsal organ with pear-shaped opening (Fig. 13). Superior claws 7-8 teeth, inferior claw 2 teeth; 2 pairs of fringed accessory claw setae present; 2 palpal claw 2-3 teeth. Colulus. Spinnerets: ALS much larger than PLS; one major ampullate (gland) spigot and nubbin on ALS. Epigynum small with scape-like median structure; anterior gonopores. Male palp with spiniform embolus, membraneous conductor. Tibial apophysis with 3 processes; the anterior process branched or un- branched, the posterior ones ‘toothed’ and facing each other. Respiratory system with 4 tracheal tubes in abdomen; broad inner tubes branching and rebranching; slender outer tubes simple. ETYMOLOGY The generic name is derived from ‘malal’ an aboriginal word for spider. Malala lubinae sp. nov. (Figs 1-9, 13-17, 20-27) MATERIAL EXAMINED TYPES. Lamington National Park, southeastern Queensland. Holotype: on Nagarigoon, 8.iv.1976, VED, NH, 820349. Paratypes: Nagarigoon, 1 6, 8.iv.1976, VED, NH, 820350; 4 2, 2 j, 820351; Binna Burra, 1 d, 1 &, 27-30.iii.1976, RJR, VED, $20352; 5 @, 11-12.i1.1981, Y. Lubin, RJR, VED, $20353; 1 9 with spiderlings in sealed leaf, S20354; Mt Hob- wee, 1 2, 3-8.iv.1976, RJR, VED, S20355; O’- Reillys, 1 d, 15-16.xi.77, VED, E. Dahms, $20356. DESCRIPTION Female: CL 3.6, CW 2.6, AL 3.8, AW 2.5. Ratio of AME:ALE:PME:PLE is 4:10:9:10; width of AR is 21, PR is 25. Sternum longer than MEMOIRS OF THE QUEENSLAND MUSEUM Pee OB-SG0R E3GCcT s y) a ¢ BY Foo) ad = = a ) x mi ive J .—) a ss is S \> 2 2 FIGS 13-15. Malala lubinae. 13, tarsal organ and bothrium, 14, trichobothrial base, 15, ¢, chelicera (prolateroventral). wide 1:0.8; endite 1:0.6. Chelicera with 5 retromarginal teeth and 5 promarginal; second proximal tooth largest. Chelicera with 2 stout frontal bristles; low retrolateral swelling near base of fang; fang with slight ventral projection. Length of coxae 1:IV is 1:0.6. Leg measurements are given in Table I. Notation of spines. Femora: palpi, DO-1-1; I, D1-1-1, PO-0-2, RO-0-2; II, D1-1-1, PO-1-2, RO-1-1; II, DO-1-1, PO-2-1, RO-1-1; TV, D1-1-1, PO-0-1, RO-0-1. Patellae: palpi, DO- 0- 1; Santen bed GB/9089 Ta0ES NAGSTeMT ty) «| | 2) BS wm = S| i) ow wi Ss = “ > x —) S cs) 5 = S| 2OaKU 3Zize2 e@e9781 ai3 FIGS 16-19. 3 palps. 16, 17, M. lubinae. 16, left palp, 17, tibial apophysis. 18, 19, M. gallonae. 18, left palp, 19, tibial apophysis. NEW SPIDER GENUS 485 mall = “BimmiS@kV 186E2 8044700 A444 tk . O@iwmiS@kY 549E2 8047700 Aa FIGS 20-25. 2 M. lubinae spinnerets, 20, spinneret group. 21, 22, 25, right ALS. 23, PMS. 24, right PLS, 486 MEMOIRS OF THE QUEENSLAND MUSEUM 30 . limmiS@kV 925E2 @888+08 AizZ BimmiSOkV 1L1ISE2 8812786 ¢ Mm OimmiSOkY 925E2 O8010700 AiZ FIGS 26-31. Malala spp. spinnerets. 26, 27, penultimate 2 M. lubinae. 26, right ALS, 27, major ampullate spigot and nubbin on ALS. 28-31 ¢ M. gallonae. 28, spinneret group, 29, right ALS, 30, PMS, 31, left PLS. NEW SPIDER GENUS palpi, D1-0-1, P1-1-0; I, P2-1-1, V7-6-2, Ri-1-1; Il, P2-1-1, W5-S-1, R1-2-0, IT, P2-1-0, ¥2-i-2, 2-1-0; TV pl-I-1, V1-1-2. R1-I-1. Metatarsi: 1, P2-2-1, ¥4-3-1, RI-1-1; I P2-1-1, ¥4-2-3, Ri-1- 2; IL, D2-2-2, P1-0-1, V2-2-1, R1-0-1; IV, D2-2- 2, P1-0-1, V2-2-1, RO-1-1. Tarsi: palpi, P2-1-0, V0-0-2. Palpal tarsi swollen distally. Dorsal ab- domen with slight foliate pattern. Epigynum very small (Figs 6-9). Spinnerets: ALS much larger than PLS (Fig. 20). ALS with one large major ampullate spigot (Map), a nubbin (n) and about 30 piriform (pi) spigots arranged in 2 groups (Figs 21, 22,25). The major ampullate spigot and nubbin are shown more clearly in a penultimate female (Figs 26, 27). PMS (Fig. 23) with large minor ampullate spigot (map), 3 aciniform gland spigots (ac) and one cylindrical gland spiget (cy}. PLS (Fig. 24) with one large cylindrical spigot and LO aciniform spigots. Other females varied in size: CL 2.9-3.9, CW 2.3-2.9, AL 3,5-4.4, AW 2,3-2.8. Male: CL 3.1, CW 2.3. AL 3.3, AW 2.0. Ratio of AMB:ALE:PME:PLE is 5:9:8:9. Chelicerae divergent: 2 stout setae (fb) crossing over frontal- ly with lesser one above; pointed spur (fs) distal to these. Four teeth on retromargin of chelicera, 4 on promargin; conical protuberance (cp) near base of fang: fang long with marked ventral projection (Figs 2.4,15). Length of coxae L:TV is 1:0,7, Leg measuremenis are giyen in Table I. Notation of spines: Femora: palpi, D0-1-1: J, D1-1-1, PO-0-2, RO-I-1, Il, DI-1-1, PQ-2-1, RO- 1-2; Il, DO-1-1, PO-1-1, RO-1-1; TV, DJ-1-1, PO-0-1, RO-O-[. Patellae: palpi. DO-O-1. Tibiae: 1, P2-I-1, V7-4-1, RI-1-1; IL, P2-1-1, V6-4-1, R1- 1-1; I, P2-1-0, W2-1-2. RI-1-1; IV, P2-0-1, V1- 1-2, R1-I-l. Metatarsi: 1. P2-1-1. V4-2-2, R]-1-1; If, P2-1-1, V3-3-2, R1-1-1; If, D0-I-1, P2-0-|, W3-2-2, R1-1-1, 1'V, D0-1-1, P1-!-1, V2- 2-2, R1-1-1. 3 palp (Figs 5,15): tegulum extended to form anterior prolateral flange, embolus, arising ventrally on tegulum, tapers to a point; conductor membraneous with pointed sclerotized tip: cym- bial tip shorter than length of tegulum. Tibia with 3 retrolateral processes, the anterior one branched. Variation in size: CL 3.1-3.3, CW 2.4-2.5, AL 3.6-3.8, AW 2.1-2.2. BroLocy The spiders were collected from branches or foliage of trees in the rainforest. The egg sac was placed with the spider in a sealed portion of the any prickly leaf blade of Calaniues muelleri, the lawyer vine. Malala gallonae sp. nov. (Figs 10-12, 18, 19, 28-31) MATERIAL EXAMINED TYPES. Holotype: ?, Bellenden Ker Range, 1054 m, 17.%-24.xi1,1981, Earthwatch/ Queensland Museum Expedition, $20357. Paratypes. Same data as holotype; | d, S20358, 1 &, §20359; 1 2, S20360. 1 3, same locality, 25-3].x.1981,520361. 1d, Malaan State Forest,, 20-4.iv.1978, RIR, VED, 820362. Upper Boulder Creek, likm NW Tully, 850-1000m, | 2, 17-18.xi.1984, J. Gallon, VED, $20363; | 2, 320364; 1 d, 6.xi1.89, GB. Monteith, 820365. Allin northeastern Queensland. Female: CL 2.7, CW 2.0, AL 3.2, AW L.9. Ratio of AME:ALE:PME:PLE is 4:8:9:8. Chelicerae with single stout elongate frontal bristles crossing each other. Four retromarginal, 3-4 promarginal teeth on chelicerac. Fang with slight yentral projection. Length of coxae 1:TV is 1:0.8. Leg measurements are given in Table |, Notation of spines: Femora: palpi, DO-)-1: I, D1-1-1, P0-2-1, R2-1-2; 1, DI-1-1, PO-2-1, RlL- 2-1; Til, DO-1-1, PO-2-1, RO-2-1; [V. DJ-1-1, POQ-0-1, RO-0-1. Patellae: palpi, DO-0-L. Tibiae: palpi, D1-0-1, P2-1-0: I, P2-1-1, V6-5-1, R2-1-1; Il, P2-1-1, VS-5-1, R2-1-1; M1, P2-i-0, V0-2-0, RJ-2-0; IV P1-1-0, V0-1-0, R1-1-0. Metatars:: I. P2-1-1, V4-2-3, R1-1-2; I, P2-1-1, V4-2-2, R2- 0-1; If, D2-2-2, P1-0-1, ¥2-2-1, RJ-0-1; lV D2- 2-2, Pl-1-1, W2-2-1, RO--I. Epigynum (Figs 10-12). Vanation in size: CL 2.6-2.8. CW 2.0-2.1, AL 3.0-3.4, AW 1.8-2.5. Male: CL 2.4, CW 1.8, AL 2.9, AW 1-4. Ratio of AME:ALE:PME:PLE is 4:8:9:8. Chelicerae slightly divergent; single enlarged setae crossing over frontally, pointed spur distally; without protuberance near base of fang. Three retromar- ginal, 4 promarginal teeth. Leg measurements are given in Table |. Notation of spines is similar to d M. lubinae, 6 palp (Figs 18,19); tegulum without prolateral flange, embolus arising prolaterally. Cymbium tip a little shorter than length of tegulum. Tibia with 3 retrolateral processes, the anterior one with 2 branches, Spinnerets: ALS (Fig. 29) have a large major ampullate spigot, a nubbin and about 20 piriform spigots. PMS (Fig. 30) have a large minor ampul- 488 TABLE 1. Leg measurements (mm) of Maiala spp. *Bowed. eg Fe [Pats Me [Ta [Milubine [2 pap ks fas foo [- fia [ar | [ee nfo [ze foe fio | imo lo [is [20 lor [73 _| ee a eo [spay suse jos fo 12 [30 Ca CFS a CY a_i fo [es t2s_o9_t97 im jos fia ie lot fea MW. galionae ® pap i jos for | [no [33 2 = 12.2 ae ivf Jor lus [a3 Jor fa — late spigot and 3 aciniform spigots. PLS (Fig.31) have 10 aciniform spigots. Variation in size: CL 2.0-2.8, CW 2.0. DISCUSSION Malala, a 3-clawed ecnibellate, has a single row of tarsal trichobothria of increasing length distal- ly and a single row of metatarsal trichobothria. The ¢ palp has 4 complex tibial apophysis and no median apophysis. The ¢ chelicerae diverge distally and have a pointed frontal spur distally. The median tracheal trunks are branched. The anterior lateral spinnerets have one major ampul- late gland spigot and a nubbin. From these and other characters Malala clearly belongs in the amaurobioid/dictynoid complex of families. In his world revision of cribellates. Lehtinen (1967) recognised one major superfamily Amaur- obioidea with 6 families. Describing New Zealand spiders, Forster (1970) and Forster and Wilton (1973) defined two groups, Dictynoidea and Amaurobjoidea, based on the branching or non-branching respectively of the median tracheal trunks. However, Gray (1983) found that Forsterina, an acknowledged close relative of Baduwinna (classified by Forster and Wilton in MEMOIRS OF THE QUEENSLAND MUSEUM Desidae: Dictynoidea) has simple median trunks thus invalidating the branching as a synapomor- phy for the dictynoids. Gray’s evidence suggests that the branching may be important only at the generic level in the same way as the extension of the trunks into the cephalothorax is regarded. In their recent paper on the higher systematics of Araneae, Coddington and Levi (1991) state that ‘these superfamilies are among the largest cladis- tic problems at the fami ly level’ and that the difficulty of definition ‘partly stems from heterogeneity within families’. | would add that the few Australian genera on which some of these families are based compared with the large num- ber yet to be described, also contributes to this difficulty. Most Australian rainforest cribellates which range in size from small to very large have a nondescript bul recognisable abdominal pattern (see Lehtinen, 1967: 435), a divided cribellar field, a single row of tarsal trichobothria increas- ing in length distally and a row of metatarsal trichobothria. The ¢ palp has a complex tibial apophysis and a median apophysis is usually present. | am persuaded to return to Lehtinen’s classification and regard these Australian spiders as belonging in the Amaurobioidea. Only one dictynid, Callevophthalmus is described from Australia. It is found in grassland and open forest and not, so far as I know, in rainforest. It ts a small spider with a distinct abdominal pattern and an entire cribellar field. Tt has no tarsal tichobothria and a single metatarsal trichobothrium, The ¢ palp has a small tibial apophysis, a large T-shaped conductor extending beyond the edge of the cymbium retrolaterally and has ne median apophysis. The ¢ chelicerae are indented prolaterally and have a proximal frontal process; these modifications do not appear to be homologous with those of Malala, Cal- Jevephthalmus is similar to Arangina from New Zealand and to Dictyna. This is the first description of spigot morphal- ogy in an ecribellate amaurobioid. In general, cursorial spiders use silk only as a drag-line, and for the construction of the cocoon in the 9. Thus, it is expected they will have fewer kinds of spigots than the web-spinning (cribellate) amaurobioids. Malala has 3 aciniform spigots on the PMS and 10 on the PLS. The typical small aciniform spigots which provide silk forswathing, prey (Kovoor, 1987) are not present in Mualala. The lack of these jn contrast to their abundance in cribellate amaurobioids and dictynoids (Cod- dington, 1990b) is probably associated with NEW SPIDER GENUS Malala’s nomadic existence. The presence of one major ampullate gland spigot (Map) and a nubbin on the ALS is found in dictynoids (notably in Dictyna) and in the Orbiculariae (Coddington, 1990a) as well as in some other taxa (Platnick e7 al,, 1991). The nubbin (presumably a remnant of a second major ampullate spigot) may be homoplasious in Malala, The fringed accessory claw setae present in Malala are probably an adaptation to tree- or foliage-dwelling and are similar to those found in some New Zealand spiders (Forster, 1970; figs 28-31) from a similar habitat. They are unlike the serrate setae which are involved in handling silk in araneoids. The presence of a narrow median sclerite above the chelicerae in Malala may be apomorphic. Marples (1962) mentions that a tri- angular sclerite is present in Matachia but not in Paramatachia, At present I am unable to place Malala in a family and consider it incertae sedis within the Amaurobioidea (sensuv Lehtinen). ACKNOWLEDGEMENTS I am grateful for the support of the Council of the Australian Biological Resources Study for funding the survey of rainforests during which some of this material was collected and for finan- cially supporting Chris Lambkin who did the lay-out for the figures. 1 acknowledge the help given by Earthwatch and the Center for Field Research, Boston, Mass., U.S.A. for supporting the Queensland Museum’s expedition to Mt Bel- lenden Ker. | thank Don Gowanlock of the Electron Microscopy Centre, University of Queensland for the scanning electron micrographs and staff of the Queensland Museum for their willing help in the preparation of this paper. 489 LITERATURE CITED CODDINGTON, J.A. 1990a. Ontogeny and homology in the male palpus of orb-weaving spiders and their reJatives, with comments on phylogeny (Araneoclada: Araneoidea, Deinopoidea). Smith- sonian Contributions to Zoology 496: 1-52. 1990b. Cladistics and spider classification: arancomorph phylogeny and the monophyly of orbweavers (Araneae: Araneomorphae: Or- biculariae). Acta Zoologica Fennica 190; 75-87. CODDINGTON, J.A. & LEVI, H.W, 1991, Sys- tematics and evolution of spiders (Araneae). An- nual Review of Ecology and Systematics 22: 565-592. FORSTER, R.R. 1970. The spiders of New Zealand, Part M11. Otago Museum Bulletin 3: 1-184. FORSTER, R.R. & WILTON, C.L. 1973. The spiders of New Zealand. Part IV. Otago Museum Bulletin 4; 1-309. GRAY, MLR. 1983, The taxonomy of the semi-com- munal spiders commonly referred to the species, Lxeuticus candidus (L. Koch) with notes on the genera Phryganoporus, Ixenticus and Badumna (Araneae, Amaurobioidea). Proceedings of the Linnean Society of New South Wales 106; 247- 261. KOVOOR, J. 1987, Comparative structure and his- tochemistry of silk-producing organs in arachnids, Pp 160-186. In, Nentwig, W. ed. ‘Ecophysiology of Arachnids’. (Springer-Verlag:Berlin), LEHTINEN, P.T. 1967. Classification of the cribellate spiders and some allied families, with notes on the evolution of the suborder Araneomorpha., Annales Zoologici Fennici 4: 199-468. MARPLES, B.J. 1962. The Matachiinae, a group of cribellate spiders, Journal of the Linnean Society of London 44; 701-720. PLATNICK, N.1, CODDINGTON, J.A., FORSTER, R.R. & GRISWOLD, C.E. 1991. Spinneret mor- phology and the phylogeny of haplogyne spiders (Araneae, Arancomorphae), American Museum Novitates 3016: 1-73. AN INVENTORY OF THE SPIDERS IN TWO PRIMARY TROPICAL FORESTS IN SABAH, NORTH BORNEO CHRISTA L. DEELEMAN-REINHOLD Deeleman-Reinhold, C.L. 1993 11 11: An inventory of the spiders in two primary tropical forests in Sabah, North Bomeo. Memoirs of the Queensland Museum 33(2): 49\-495. Brisbane. ISSN 0079-8835. Collecting trips were made to a primary rainforest area at 1500-1900m altitude (Mi Kinabalu National Park) and a primary lowland rainforest (Danum Valley Field Centre} jn Sabah, North Borneo. For comparison, a strongly degraded secondary forest in the town Kota Kinabalu was also sampled. All the material, with the exception of the mygalomorphs and salticids, has been identified and compared with collections from Sarawak, Kalimantan and Sumatra. 254 species were distinguished in approximately 120 genera, 35 could be identified as known species, seven of which were clearly synanthropic, the rest are undescribed. 207 species were found in one locality only: 85% of the species from Kinabalu, 70% of the species of Danum and 50% of the species from the town park. Widespread species were found mainly in the Araneidae, Pholcidae, Oonopidae, Clubionidae and Salticidae. A list of the genera and species is given, (Biodiversity, rainforest, Asia, Araneae. Christa L. Deeleman-Reinhold, Sparrentaan 8, 464] GA Ossendrecht, The Netherlands; & April, 1993. Tropical rainforests, covering only 6% of the Earth’s surface, are believed to harbour more than half of all terrestrial animal species, of which less than 10% are described at present (Stork and Gaston, 1990), Inventorying the spider fauna of rainforests in south-east Asia has given spider taxonomy a new turn, especially so after the introduction of a new sampling method that tar- gets canopy arthropods, Most rainforests in Asia have now been destroyed or degraded, but the number of un- described species is still overwhelming. The rapid destruction of our rainforests is an incentive to securing as much data as possible as ... “an extensive program of inventorying aimed at és- timating diversity of species ... is essential for a fuller understanding of the role of biodiversity in ecosystem function" (Coddington et al., 1992). Records of spiders from Borneo are extremely poor. With more than 30,000 species of spiders described so far, only about 160 named spider species have been described or recorded for the whole of Bomeo; 65 of these are salticids. Only 96 spider species were reported from Bormeo before World War 1. Wanless and Hillyard (1984) present a list of species collected during the arachnological survey of Gunung Mulu National Park, Sarawak, 360 species were collected in all families, 38 of which were identified with known species, another 14 with reserve; 20 identified species are salticids. From Sabah, a mere 20 spider species are known, all published since 1979 (Deeleman-Reinhold, 1980, 1987, Leh- linen, 1979, 1981, 1982: Levi, 1982, 1985; Okuma, 1988; Platnick and Murphy, 1984; Wan- less, 1987). Ina privately undertaken program of inventory- ing spiders of primary and secondary forests in south-east Asia, during the last 14 years 1 have been engaged, with the help of other, partly autochthonous collectors, in surveying the spider fauna of south-east Asia, mainly Indonesia, Malaysia, Thailand, Sri Lanka and the Philip- pines. As part of this initiative, 1 made three collecting trips to Sabah in the north-eastern part of Borneo. METHODS In June 1979, July 1980 and April-May 1991, 1 collected spiders in the primary rainforest of Mount Kinabalu National Park at altitudes of 1500-1900m, In May 1991, 2 days were spent collecting at an altitude of 500m (Poring Hot Springs). In May 1991, spiders were collected in lowland primary forest around the Danum Valley Field Centre in eastem Sabah. For comparison, some time was also spent collecting in the town park in Kota Kinabalu. The spiders were collected by hand picking, sweeping, liller sieving and pitfall trapping on the ground, All araneornorph spiders, with the excep- tion of the Salticidae have been identified (Tables 1-3). The collected spiders were compared with most specimens of the above mentioned south- cast Asia collection. Identification was done as Donopidae Dysderina sp. (1) Gamasomorpha sp, (2), Sabah sp. (2 Ischnothyreus sp. (4) Opapaed" (1) Orchestina sp. (1) sp. (1), Sabah, only below 600m Plectopilus sp. (1) Xyphinus lemniscatus Deeleman sp. (1), * Undeseribed genus (1), also lower in secdn- forest Tetrablemmidse Ablemina Borneomma Subuhya cireumspectans Deeleman, also lower in secondary forest roberti Deeleman hinabaluang Deelerman bispinosa Deeleman sp. (1)* Ochyroceratidae Psiladereces sp. (1) Spéocera sp. (1) Undesenbed genus (1) wlidae Scytodes pallida Doleschall, Widespread* Pholeidae Uthina sp. (1), Sabah sp. (1)* Spermophora sp. (1), Sabah miser Bristowe, widespreud* Belisana sp.) Undescribed genus (1) Heteropadidae Heteropeda sp. (1) sp. (1)eanopy walk* Thelcticopis sp, (1) Olios sp. (1)* Undesenibed genus (1), in grass Undescribed genus (1), canopy walk" Cienidae Ctenus sp, (1) Clubionidae s.1. Clubioninae Cheiracanthium:sp, (1) Clubiona sp, (4) ap. (1) canopy wilk* sp. (1 widespread Phrucolithinae Otacilia sp. (1), also at 500m Sesieutes sp. (1), Sabah sp, (1) Teutamus sp. (1) Orthobula sp, (1), Sabah Connninge New genus (1) Gnaphosidue Jocaena sp. (1), on the lawn Palpi ‘ae ipi e Boagrius sp. (1) Zodariidee Asceua sp. (1) sp. (1)* Malinella sp. (3) ndeseribed genus? (2) Thomisidae Borbaropactus sp. (1) Lycopus sp. (1), alsa at 500m Misumenops sp, (1), canopy walk* Pagida sp. (1) Phoyuerachne sp. (1) Onyopidae Cuyopes sp. (1), canopy walk* ridge Polviaea sp. (1) Lycosidae Pardosa sp, (1) Undesenbed genus (1) Hippasinae (1) Hubnidie Alistra sp. (1) Hahnia (2) Hersiliidae Hersilia sp. (1) Theridiidae Aharanes mundila (L. Koch), wide- sprea fepidarivrum (C.L. Koch), worldwide Aneloximus sp. (1), canopy walk* Areyrodes xiphias Thorel, widespread Rhomphaea sp.(1) Chrysse sp. (1) Coleusoma sp. (2), Sabalt Coscinula sp. (1) sp, (1) Dipoena sp. (5) sp. C1)" Episinus sp. (2) Janula sp. (1), Sabah MEMOIRS OF THE QUEENSLAND MUSEUM Meotipa sp. (1)* Pharoncidia sp. (2), Sabah sp. (1)* Theridion sp. (4) spp. (3)*, 1 on. canopy walk Undescribed genus (2) sp. (1), also at 500m Undesenbed penus (1) Mimetidae Mimetus sp. (3) Theridiosomatidac Plato sp. (1) Theridigsoma sp, (1) Mysmenidae Undeseribed genus (1) Tetragnathidae Leucauge celebesiana Walckenaer, widespread spp. (2), Sabah Glenognatha sp. (1) Mesida sp. (4) Undescribed genus 1 (2) Undescribed genus {1 (2), also at 500m Undescribed genus 1, (1), also at 500m Araneidae Araneus sp. (1) Armiope reinwarini Doleschall, widespread aemula (Walckenaer), widespread Cyelosa bifida Doleschall, widespread. Cyntophora sp. (1) ? Briephera sp, (1) Gasteracantha sp. (1)* Milonia brevipes Thorell, widespread Neoscena nartica L. Koch, world tropics Undescribed genus (1) Linyphiidae Neriene beccarit Thorell, widespread Kuala sp. (1) Parameioneta sp. (1) Naseona sp. (3) ap. (1)* Undeseribed genus I (i) Undesenbed genus 1 (1) Undescribed genus TV (1) Undescribed genus V (2) Uloboridae Philaponelia sp. (1) Uloboray lugubris Thorell, widespread? Psechridae Psechrus kinabaly Levi Table 1, Spiders from Mount Kinabalu, 1500-1900m (Headquarters and Power Station) and 500m (Poring Hot Springs), primary rainforest, 18 collecting days in April-May, June and July. Family order is ‘phylogenetic’, List gives no, of undescribed species in parentheses and notes on species.*= only at 500m. muchas possible with the aid of modem revisions but, where these do not exist, I had to rely on the keys m Simon (1892-1903) and the Latm descriptions (with- out illustrations) of Thorell (1877-1899) and Simon. Many nineteenth century types deposited in Genoya, Panis and London were studied. Only species of which adults were collected are considered here. RESULTS From the three main prospected localities in Sabah, a total of 254 species from most spiders families (for practical reasons the mygalomorphs and the salticids were excluded) could be distin- guished. Of these, 35 species could be identified as described species, seven of which are clearly synanthropic. On Mt Kinabalu (1S00-1900m), 135 species were collectedin 18 days (41 species represented by one specimen only); 25 species were collected in two collecting days at Poring Hot Springs, lower down on the mountain slope at 500-600m; four of these were shared with the 1500-1900m site (see Table 1). For six of the 19 described and named species this is the type locality (Deeleman-Reinhold, 1980, 1987; Levi, 1982). 132 species (85%) were collected only in Kinabalu; 24 species were also found elsewhere. FOREST SPIDERS OF SABAH, NORTH BORNEA Gonopidae Dysdering sp. (1) Gamasomerplu sp. (2), Sabah Ischnothyreus peltifer (Simon), world tropics sp. (5) Opopuea ? sp. (1), Sabah Orchestina sp. (1) Plectopilus sp. (1), Sabat Xyphinus sp. (1) ‘Tetrablemmidae Ableruna sp. (1) Ovhyroceratidae Merizocera sp, (1) Speocera sp. (1) Pholcidae Calupnita phasmoides Decleman, Bomec Smeringopus pallidus (Blackwall), world topics Pholcus sp. (2) (1) in logged area Spermophora sp. (1), Sabah Belisana sp. (1) Heteropodidae Heteropoda sp. (1) sp. (1), in logged area Oliog sp. (1) Cleni Ctenus sp. (1) Gnaphosidae Micyihus sp. (1)widespross ae ae ™ Clubioninae Cheiracanthium sp, (1) Clubiong sp, (3) Castianeirinae Aefius sp. (1) Mirurolithinac Sesieutes sp. (1), Sabah Connninae Undescribed genus (1) Palpimanidue Boagrias sp. (1) Zodariidge Malinella sp. (2) Thomisiid Barbonopartas ap. (1) Losabares:sp. (1), in log; = ata Payida sp. (1), in loge Pentraeus sp. (1) Synema sp. (1) Talaus sp. (1), in lopged area Tmarus sp. (2), in logged area Pisauridac Polybaea sp. (1) Oxyopidae sa ast lineatipes C.L. Koch, widespread sp. (1) Tapponia superba Thorell, widespread Lycosidae Hippasa Wadicosa birmanica (Thorell), widespread, int Pardesa ala (Th (Thoreil). widespread Hahniidae Alixira sp. (1) Hersilitclue Hersilia sp, (1) Theridiidae Achuearanea sp. (1) Arpyrodes sp. (1) Cephalobares sp. (1) Chirysso sp. (1) Caleasama sp, (1), Sabah Coscinida sp. (1) Diperena sp. (2) Episinus sp. (1) Janula 9p. (1), Saba Theridion sp. (4) Undescribed genus {1} Mimetidae Mimetus sp. (1) Mysimenidae Undescribed genus (1) Anapilse Pseudanapw paroculus Simon, widespread Leucauge sp. (1), Sabah sp. (1) Glenoynatha sp. (1) Aruncidag Caerosiris sp. (1) Cyclosa bifida Doleschall, widespread mulmeinensis (Thorell), widespread Gasteracomha sp. (1) Ge subarmata Thorell, widespread Larinia phthisica L. Koch, widespread Milonia trifasciate Thorell, widespread Neoscona nautica L. Koch, world tropics sp. (1) Paltys sp.{h) Undeseribed genus I (1) Undesenibed genus Il (1) Linyphiidoe Undescribed genus (1) Uloboridae Phileponella sp, (2) 493 Table 2. Spiders from Danum Valley Field Centre, primary lowland forest, 8 collecting days in May; some species, mostly Thomisidae, in freshly logged area. Family order is ‘phylogenetic’ - List gives no_ of undescribed species in parentheses and notes on species. Compared to the lowland catches, a predominance of Linyphiidae was found. In primary lowland forests around Danum Val- ley Field Centre in East Sabah, 90 species were vollected in 9 days (Table 2); 14 species have been previously described. Of these, 67 species (70%) were only found at Danum, and 23 were also found elsewhere. In a freshly logged area, thomisids were particularly diversified. In the secondary forest of Signal Hill in the township of Kota Kinabalu, 16 species were col- jected, 7 of which could be identified to species. Eight species. were found also elsewhere, and § species (50%) were collected only on that site, DISCUSSION The main conclusion 1s that in tropical forests, spider species known from only one locality are enormously preponderant even though all dis- tribution types from cosmotropical to very restricted ranges were encountered, Ina total of 254 species from the three localities (Tables 1-3), 207 were collected at one locality only, 92 of which were ‘singletons’. Is this due to the lack of data only, or is a high percentage of endemic species real? This phenomenon occurs much more frequently in some families than in others. Quite often, in adjacent localities a sister species is found. Ina long-term inventory of a 1-2 km* aréa on the northern side of the Sibolangit range, on Gunung Leuser in Sumatra (Deeleman- Reinhold, unpublished data), spiders were col- lected once a week fortwo years. A similar study was conducted on the other side of the ridge. Less than half of the species were found on both sides of the range! Therefore, endemism in spiders seems characteristic of primary rainforests, even though the real extent of distribution ranges will only be revealed after long and extensive sam- pling. For example, recent studies on south-cust Asian Linyphiidae (Millidge and Russell-Smijh, 1992) report 27 species, 26 of which new, described in 1] new and four known genera, all new species were recorded from only one locality (see also Scharff, 1992), Also, widely distributed species were often found in human-made habitats. In such habitats most species described in the last century were found, In the course of identifying large south- 494 Oonopidae Ischnothyreus peltifer (Simon), world tropics sp. (1) Plectoptilus sp. (1) Ochyroceratidae Psiloderces sp. (1) Theotima minutissima (Petrunkevitch), world tropics Pholcidae Uthina luzonica Simon, widespread Ctenidae Ctenus sp. (1) Clubionidae s.1, Palpimanidae Boagrius sp. (1) Theridiidae Janula sp. (1) Psilochorus sp. (1)widespread Oedignatha scrobiculata Simon, widespread Theridion tenuissima Thorell, widespread MEMOIRS OF THE QUEENSLAND MUSEUM sp. (1) Tetragnathidae Leucauge sp. (1) Araneidae Neoscona punctigera Doleschall, widespread Uloboridae Uloborus humeralis Hasselt, widespread Table 3. Spiders from town-park Signal Hill, Kota Kinabalu (2 collecting days). Family order is ‘phylogenetic’. List gives no. of undescribed species in parentheses and notes on species. east Asian collections it appeared that the majority of the species described prior to the early 20th century occur in habitats created by humans rather than in the rainforests. Thus, the spider fauna of the latter is still almost unknown. A high degree of endemism seems to occur in certain families; other families which include a relatively high number of widely distributed species are Araneidae, Gnaphosidae, Oonopidae, Pholcidae and Salticidae. Occasionally, one or two species in a family are able to disperse con- siderably, whereas their relatives have remained limited to a restricted area. Among the best dis- persers are some of the smallest known litter- dwelling spiders, with a body length of less than Imm, which independently seem to have developed methods to overcome the vicissitudes of ballooning, e.g. the tiny armoured anapid Pseudanapis paroculus Simon is distributed over much of tropical south-east Asia both in primary and secondary forests. The small ochyroceratid Theotima minutissima (Petrunkevitch) and the oonopid spider Ischnothyreus peltifer (Simon) are distributed over the palaeo- and neotropics, where they live side by side with local congeners. Also larger spiders have been found to be widely distributed in humid forest, such as some Cyclosa, Argiope, Acusilas, Neoscona and Gasteracantha species, but also the delicate, al- most transparent pholcid Calapnita vermiformis Simon. The number of small-range species in both primary and secondary evergreen forests seems to be enormously higher than we are used to in temperate climates. Very few wide-spread species seem to occur naturally on Mount Kinabalu; more were found in lowland forest. It is premature to estimate the total number of species present. Richest in species probably is the family Salticidae. Also numerous in species are the Theridiidae, Oonopidae, Araneidae, Clubionidae s.]. and Tetragnathidae in that order (see also Wanless and Hillyard, 1984 for Gunung Mulu). Some genera have been particularly speciose in primary forest. In /schnothyreus I found 11 species in Sabah (10 undescribed); in Theridion 11; in Dipoena 8; and in Clubiona 8 (all un- described), One final remark on diversity. Among the strongly represented families, diversity in the fol- lowing families appears to be higher than average: Pholcidae, Clubionidae s. lat., Tetrag- nathidae, Araneidae, Linyphiidae. This study indicates that, when replacing primary forest by secondary plantations, the loss of species diversity of spiders is enormous. ACKNOWLEDGEMENTS Mr. Mh. Yusof of SERU, Kuala Lumpur kindly provided me with a research permit for 1991. AKZO Resins, Bergen op Zoom donated the al- cohol for preservation. LITERATURE CITED CODDINGTON, J.. HAMMOND, P., OLIVIER], S., ROBERTSON, J., SOKOLOV, V., STORK, N. & TAYLOR, E. 1991. Monitoring and inventory- ing biodiversity from genes to ecosystems. Pp. 83-117. In, Solbrig, O. (ed.), ‘From genes to ecosystems: a research agenda for biodiversity.’ (IUBS: Paris). DEELEMAN-REINHOLD, C.L. 1980. Contribution to the knowledge of the southeast Asian spiders of the families Pacullidae and Tetrablemmidae. Zoologische Mededelingen 56: 65-82. 1987. Revision of the genus Xyphinus Simon (Araneae: Oonopidae). Acta Arachnologica 35: 41-56. LEHTINEN, P.T. 1979. Spiders of the Oriental- Australian region I. Lycosidae: Venoniinae and Zoicinae. Annales Zoologici Fennici 16: 1-22. 1980. Spiders of the Oriental-Australian region III. Tetrablemmidae, with a world revision. Acta Zoologica Fennica 162: 1-151. 1982. Spiders of the Oriental-Australian region IV. Stenochilidae. Annales Zoologici Fennici 19: 115-128. FOREST SPIDERS OF SABAH, NORTH BORNEA LEVI, H.W. 1982. The spider genera Psechrus and Fecenia (Araneae: Psechridae). Pacific Insects 24: 114-138. 1983. The orb-weaver genera Argiope, Gea and Neogea from the western Pacific region (Araneae: Araneidae, Argiopinae), Bulletin of the Museum of Comparative Zoology, Harvard 150: 247-338. MILLIDGE, A.F. & RUSSELL-SMITH, A. 1992, Linyphiidae from rainforests of Southeast Asia. yey Journal of Natural History 26: 1367- 1404. OKUMA, C. 1988. Five new species of Tetragnatha from Asia (Araneae: Tetragnathidae. Esakia 26: 71-77. PLATNICK, N.I. & MURPHY, J.A. 1984. A revision of the spider genera Trachyzelotes and Urozelotes (Araneae, Gnaphosidae). American Museum Novitates 2792: 1-30. SCHARFF, N. 1992. The linyphiid fauna of eastern Africa (Araneae: Linyphiidae) - distribution pat- terns, diversity and endemism. Biological Journal of the Linnean Society 45: 117-154. SIMON, E. 1892-1895. ‘Histoire Naturelle des Araignées’ vol, 1. 2nd edition, (Encyclopédie Roret: Paris). 1897-1903. ‘Histoire Naturelle des Araignées’ vol. 2, 2nd edition, (Encyclopédie Roret: Paris). STORK, N. &GASTON, K. 1990. Counting species 495 one by one. New Scientist ,11 August 1990: 43- 47. THORELL, T. 1877. Studi sui Ragni Malesi e Papuani I. Annali del Museo Civico di Storia Naturale Giacomo Doria, Genova 10: 341-634. 1878. Studi sui Ragni Malesi e Papuani II. Annali del Museo Civico di Storia Naturale Giacomo Doria, Genova 13: 1-317. 1881. Studi sui Ragni Malesi e Papuani II]. Annali del Museo Civico di Storia Naturale Giacomo Doria, Genova 17: vii-xxvii, 1-720. 1890a. Studi sui Ragni Malesi e Papuani IV, 1. Annali del Museo Civico di Storia Naturale Giacomo Doria, Genoya (2) 8: 1-419, 1890b. Diagnoses Aranearum aliquot novarum in Indo-Malesia inventarum. Annali del Museo Civico di Storia Naturale Giacomo Doria, Genova 30: 132-172. 1892. Studi sui Ragni Malesi e PapuanilV,2. Annali del Museo Civico di Storia Naturale Giacomo Doria, Genova 31: 1-490. WANLESS, F.R. 1987. Notes on spiders of the family Salticidae 1. The genera Spartaeus, Mintonia and Taraxella. Bulletin of the British Museum of Natural History (Zoology) 52: 107-137. WANLESS, F.R. & HILLYARD, P.D. 1984. Arach- nological notes from Gunung Mulu National Park with a list of the spiders recorded from Borneo and a preliminary list of the harvestmen of the Park. Sarawak Museum Journal 51 (ns) 30: 53-64. A REVIEW OF FACTORS INFLUENCING THE DISTRIBUTION OF SPIDERS WITH SPECIAL REFERENCE TO BRITAIN ERIC DUFFEY Doffey, E. 1993 11 11; A review of factors influencing the distribution of spiders with special Teference to Britain. Memoirs of the Queensland Museum 33(2): 497-502. Brisbane. ISSN 0079-8835. Available data on factors influencing spider distribution are synthesized using mainly British and other European information. The importance of landscape history is stressed, in frag- menting ancient natural habitats and creating new ones, [tis postulated that this has reduced the number of specialists and allowed a range expansion of pioneer and euryoecious species. A tentative classification of life strategies is proposed. Habitat diversity and microspatial distribution are discussed with examples, DSpiders, habitat preferences, geographic dis- tribution, life strategies. Eric Duffey, Cergne House, Wadenhoe, Peterborough, PES SST, United Kingdom; 3 November, 1992. Many attempts have been made to categorise the habitats of spiders according to their preferen- ces for dampness, dryness, shade, light, warm or cool temperatures. In addition, increasing knowledge derived from extensive collections made during the last 50 years in Britain and the rest of Europe have made it possible to draw distribution maps (Locket ef al., 1974: Ransy and Baert, 1985. 1987a, 1987b; Janssen and Baert, 1987; Ransy et al., 1990; Alderweireldt and Muelfait, 1990; Canard, 1990), even though their incompleteness is acknowledged. The distribu- lion of some species shows a clear influence of latitude and longitude, with north-south or east- west trends, or an association with major habitat formations. This paper discusses some factors which influence spider distribution, such as landscape history and geographic range, habitat preferences, adaptation to man-made biotopes and small-scale environmental differences, with the object of categorising the occurrence of species according to life strategy. Islands of modest size such as Bnitain are poorer in Species than adjacent continental areas. For example, the spider fauna of Belgium, a near neighbour, which is only 1/8th the size of Britain und has 75km of coastline compared with Britain's 19000 km, and a lower landscape diver- sity, has almost as many recorded species (600) {Keckenbosch ef al., 1977) as Britain’s 622 (Roberts, 1985-87). Habitat labels based only on local information may be unsatisfactory, since (in Britain and the rest of Europe) we know that (a) some widespread species are found in different habitats according to where they occur in their geographic range; (b) within a restricted area some species are found only, or mainly, in 2 very different habitats, for example sand-dunes and marshes; (c) some species are so widespread that they are difficult to characterise in terms of habitat preferences: (dl) species confined to only one specialised habitat are generally few im number and often rare. Ex- amples are presented in this paper. Nomenclature follows Roberts (1985-87) for spiders and Anon. (1964-80) for plants. LANDSCAPE HISTORY AND PATTERN OF SPIDER DISTRIBUTION Britain was largely forested before human set- tlement but forests are now much modified scat- tered remnants. This extensive environmental change will have favoured some species and dis- advantaged others. For example, when the sur- viving rare species associated with major formations in Britain are listed (Table 1) most are recorded for coastal systems which-apart from the more limited mountain tops—are the least modified components of the present-day landscape. Species which are regarded as ‘char- acteristic’ of major habitat formations (Ratcliffe, 1977) (Table 2) may also be identified. The nigh numbers recorded for grassland, dry heaths and coasts probably reflect a great expansion of range by open-ground species after forest clearance, The extent of habitat modification and distur- bance is difficult to quantify because the type and intensity of change varies from place to place. In the case of wetlands, however, there is a common factor in that alteration to the water table has a greater impact on the fauna than other uses made 498 TABLE 1. Numbers of British spider species in the IUCN categories Endangered, Vulnerable and Rare, assigned to major habitats (compiled by P. Merrett in Bratton, 1991). Coast- dune, shingle, saltmarsh, cliff Dry lowland heaths Fens-mesotrophic to eutrophic Deciduous woodlands in lowlands Caledonian (ancient) pine forest, Scotland Grasslands-acidipholous to calcicolus Wet heath/bog—oligotrophic Open moorland, uplands and mountains of these areas by man. In 1969 11 fens in East Anglia were surveyed by a group of arach- nologists hand-collecting for a total of 10 hours per site. Each hourly collection was kept separate. The similarity between the faunas of the 11 fens in terms of abundance of each species present was assessed using Mountford’s Index of Similarity (Mountford, 1962). Three groupings were derived, of which 2 were more similar than either was to the third group. The 8 fens in groups 1 and 2 had survived with little change to their water regimes at that time, while the third group had suffered falling water tables and hence vegetation changes (Duffey, 1974). The mean numbers of species for groups | and 2 were 53.2 and 50.0, respectively, and 34.6 species for group 3. Most of the rarer and more specialised fen species (Marpissa radiata (Grube, 1859); Hygrolycosa rubrofasciata (Ohlert, 1865); Neon valentulus Falconer, 1912; Carorita paludosus Duffey, 1971; Centromerus incultus Falconer, 1915; Maso gallicus Simon, 1894) were recorded in groups | and 2. HABITAT VERSATILITY IN SPIDERS The ability of many spiders to live successfully in a range of different environments has been little studied. The best known examples are pioneer species that are good aeronauts and the first to colonise newly created habitats. Meijer (1977) discusses this for Dutch polders, and Duf- fey (1978) for croplands and grasslands. Not all aeronauts behave in this way. Erigone arctica (White, 1852) and E. longipalpis (Sundevall, 1830) are often abundant on coastal driftlines and saltmarshes but are rare inland. The former is found on mountainsides in Sweden (the late A. Holm, pers. comm.) and both have been recorded on inland saline areas as well as in sewage works. MEMOIRS OF THE QUEENSLAND MUSEUM TABLE 2. Numbers of British spider species assessed as characteristic of various major habitats (compiled by P. Merrett in Ratcliffe, 1977) Dry lowland heaths Deciduous woodlands Fens Open moorland Caledonian pine forest This provides evidence that they disperse over long distances but survive in only a few places. Agricultural land has been colonised by species whose natural habitats are sand-dunes and stony open ground, for example Troxochrus scabriculus (Westring, 1851) and Milleriana in- errans (O.P.-Cambridge, 1884). Porrhomma convexum (Westring, 1861) is also frequent on cultivated Jand but elsewhere occurs in caves, mines, culverts (Locket and Millidge, 1953), and under stones by stream and lake shores (K. Thaler, pers. comm. and Duffey, unpublished). The stone-filled filter beds of sewage works attract another cave species, Lessertia dentichelis (Simon, 1884), together with Leptorhoptrum robustum (Westring, 1851), whose natural habitat is freshwater marshes and wet meadows, and also E. longipalpis and P. convexum. The environment of filter-beds is completely artificial and uniform with stable temperature and high humidity, forming a ‘super habitat’ in which few species occur but in much higher numbers than found in nature. The ability of some species to live successfully in two contrasting habitats was first noted by Bristowe (1939) and described as ‘diplostenoecism’ by Duffey (1974) and ‘doppel- tes 6kologisches Vorkommen’ by Schaefer and Tischler (1983). The best-known examples are those species found on coastal dunes and also in marshes—Synageles venator (Lucas, 1836), Tibel- lus maritimus (Menge, 1875), Clubiona juvenis Simon, 1878, Hypomma bituberculatum (Wider, 1834) and Thanatus striatus C.L. Koch, 1845. The last is also found in dry grasslands. Sitticus rupicola (C.L. Koch, 1837) is widespread on stony mountainsides in central Europe (Proszynski, 1978) but in England occurs only on coastal shingle banks. Competitive relationships may also influence choice of habitat and hence distribution. Zelotes electus (C.L. Koch, 1834) is the characteristic species of this genus on coastal sand-dunes in FACTORS INFLUENCING SPIDER DISTRIBUTION | fi A : ie Ail [=f Al feach a LSS FIGS 1A-C. Distribution of spiders on 2.5x2.5m plot divided into 25x25cm quadrats on a Danish heath- land. 1A. Vegetation map: Blank space, heather; lined shading, grass tussocks; cobbled, mosses, lichens and small stones. FIG. 1B. Trichopterna cito. A small web-spinning linyphiid almost confined to open ground with short, sparse vegetation; not a known active aeronaut nor a pioneer (Table 3) but a Narrow Specialist. Spread of heather eliminates it. 499 Britain whereas Z. pusillus (C.L. Koch, 1833) is associated with inland heaths, dry grasslands and open, stony ground. However, Z. electus was found (Anon., 1979) to extend only as far north as south-east Scotland and at higher latitudes was replaced on the coastal dunes by Z. pusillus. All these species can adapt to different environ- mental conditions and emphasise the need to study habitat selection throughout the whole geographic range of a species before its distribu- tion status can be understood. EFFECTS OF HABITAT FRAGMENTATION Several distribution maps in Locket et al. (1974) show widely scattered records for certain species which may indicate a decline from a former continuous distribution. Lepthyphantes midas Simon, 1884 is an ancient forest specialist and is associated with loose bark and dead timber or birds’ nests made of twigs. It is only known from 4 scattered sites in Britain where ancient forest survives. Similarly, wet- lands have suffered serious losses, including the Fen Basin, East Anglia, which was progressively drained from Roman times and lost the remaining large areas of marsh in the mid-19th century. The local lycosid Hygrolycosa rubrofasciata (Ohlert, 1865) survives in the two remaining fenland areas and also in numerous small fen relicts around the d s FIG, 1C. Other species preferred cover of heather plant or grass tussocks, e.g. Scotina gracilipes (Blackwall, 1859) (s) and Dipoena prona (Menge, 1868) (d). Each record refers to a catch of 1-5 individuals. 500 TABLE 3. Classification of life strategies and adap- tability to environmental diversity based on British spiders. PIONEER SPECIES Active aeronauts which disperse freely, exploiting newly created open ground where competition is low. Widely distributed in temporary or changing habitats such as agricultural cropland, gardens, urban areas, leys and other types of disturbed ground or vegetation. GENERALISTS Common species with a capacity to adapt to a wide range of semi-natural habitats and permanent ar- tefacts in the man-made environment. May be difficult to assign to a particular habitat. BROAD SPECIALISTS A. Widespread, euryoecious, or ‘characteristic’ species (Table 2) associated with major habitats such as deciduous woodland, marshes, heaths or ancient grassland, but may be found in many dif- ferent variants of the chosen major formations. B. Diplostenoecious species, mostly widespread and associated with 2 different habitats but usually more common in one than the other. Occasionally much more abundant in man- made habitats than in the natural environment. This grouping grades into species successful in 3 or more different en- vironments. NARROW SPECIALISTS Stenoecious species which seem confined to clearly defined habitat. Includes rare species in low num- bers and others which may be locally abundant, although confined to a restricted area because the habitat is scarce. margins of the Fen Basin. Are these relicts of a former more extensive distribution? Lowland heathland has also suffered severe losses, having been reduced to many small frag- ments by agricultural reclamation with a conse- quent loss of biodiversity (Webb, 1990). Eresus niger (Petagna, 1787) was formerly more widespread in heaths in southern England but is now known from only one locality where the population is small. In contrast, some species are able to live in a range of different habitats, and thus overcome the problem of fragmentation. If this characteristic is also combined with active aeronautic dispersal, the chances of finding isolated suitable environ- ments will be further enhanced. For example, MEMOIRS OF THE QUEENSLAND MUSEUM Pardosa palustris (L., 1758) is the most active aeronaut of the common lycosids found in Britain and northern Europe (Richter, 1970). Few have been recorded in a wide variety of habitats, in- cluding marshes, grasslands, heathlands, and agricultural crops, but occasionally is found to be dominant, as in moist hay meadows in river val- leys and on some sand-dunes. In a survey of dune systems in Scotland (Anon., 1979) it was the most abundant lycosid, although it was not recorded on all the dune areas which were studied. It seems that the active aeronautic behaviour of P. palustris enables it to move about freely and its ability to exploit many different habitats gives it a high ranking as an opportunist. Kessler (1973) also showed that P. palustris is able to produce more eggs per unit of body size under field con- ditions than 7 other Pardosa species. This may be an advantage when colonising new areas. Adaptability to environmental diversity varies from species to species, so that a gradient exists from those which are very widespread (usually many species) to those which appear to be con- fined to a specialised habitat (relatively few species). The different components of this gradient are outlined in Table 3, and modified from Duffey (1975a). HABITAT DIVERSITY AND MICROSPATIAL DISTRIBUTION The structure of the vegetation, the litter layer and physical features of the environment have a strong influence on spider distribution and species composition (Duffey, 1962, 1968, 1974; Edwards et al., 1975; Uetz, 1991). There is evidence that all species, however widespread, are influenced in some way by habitat structure. This was shown by comparing the fauna in dif- ferent quadrats of a simple vegetation type on a Danish heathland (Duffey, 1974). Fig. 1 shows the differences in species and numbers of spiders between 100 25x25cm quadrats in a block measuring 250x250cm. The vegetation consisted of a heather plant (Calluna vulgaris (L.) Hull, 1808) in one corner of the block, and a few scattered grass tussocks of Deschampsia flexuosa ((L.) Trin., 1836), while most of the area was covered with mosses, lichens and small stones, The species in Fig. 1 occurred in clearly defined microhabitats. Trichopterna cito (O.P.- Cambridge, 1872), which was widespread in the open ground of moss and lichen, avoided the heather, and was also absent from 4 quadrats on the right-hand side of the sampling area which FACTORS INFLUENCING SPIDER DISTRIBUTION had been trampled. Similar results are reported by Jocqué (1973), who studied the fauna of different types of woodland litter layers in Belgium. On a heathland ranging from dry to wet areas, Snazell (1982) sampled the spider fauna by pitfall trap- ping at 154 random points over 12 months. By Principal Components Analysis on the 45 most numerous species he was able to show a wide gradation from specialised to broad habitat preferences, which conform well with the categories in Table 2. In an experiment in tall grassland in England, faunal changes were recorded in grass litter modified by trampling. Samples of grass litter enclosed in nylon-mesh bags (20x20x8cm) received 3 different treading treatments (5 treads/month, 10 treads/month and an undis- turbed control series) (Duffey, 1975b). There were 25 replicates in each case. After 12 months the volume of the litter in the controls had fallen by 50 % due to natural decay, but those having had 10 treads/month had fallen by 81 %. Of the 10 most frequent species, 5 were eliminated by the treading after 12 months, and the total num- bers of all species fell by 84 %. Of the 5 remaining species, 3 showed little response to the treading, their numbers falling only marginally. The higher level of treading in this experiment was very light compared with that on a public footpath in a popular area, but the effect on the litter fauna was quite dramatic. CONCLUSIONS The modification of the European landscape through many centuries has been the greatest influence determining the distribution of spider species. Natural and near-natural habitats are now rare, as are the specialist species associated with them. Today many species have adapted to man- made environments, whether permanent or tem- porary, and those preferring open-ground conditions have greatly expanded their range. A gradation of life strategies (or adaptability) from pioneer species to narrow specialists is proposed. Superimposed on these factors are the influences of major climatic zones and the microspatial variations in the abiotic environment. All these features should be considered when defining the distribution and habitat characteristics of a species, drawing on evidence from the whole geographic range. 501 ACKNOWLEDGEMENTS My grateful thanks to Malcolm Mountford and David Spalding for statistical help with the Index of Similarity. LITERATURE CITED ANON. 1964-80. ‘Flora Europaea’. 5 vols. (Cambridge University Press, Cambridge). 1979. ‘The invertebrate fauna of dune and Machair sites in Scotland, Vol.l’. (Project 469 Report to Nature Conservancy Council: Peterborough). ALDERWEIRELDT, M. & MAELFAIT, J.-P. 1990. ‘Catalogus van de Spinnen van Belgie, Deel VII, Lycosidae’. (Studiedocumenten No. 61, Koninklijk Belgisch Instituut yoor Natuur- wetenschappen: Brussel). BRATTON, J.H. (ed.) 1991. Arachnida. 121-219. In ‘British red data books. 3. Invertebrates other than insects’. (Nature Conservancy Council: Peter- borough). BRISTOWE, W.S. 1939. ‘The comity of spiders, Vol. 1’. (Ray Society: London). CANARD, A. (ed.) 1990. Araignées et scorpions de Youest de la France: catalogue et cartographic provisoire des espéces. Bulletin de la Société Scientifique de Bretagne 61(1): 1-302. DUFFEY, E. 1962. A population study of spiders in limestone grassland: description of study area, sampling methods and population characteristics. Journal of Animal Ecology 31: 571-599. 1968. An ecological analysis of the spider fauna of sand dunes, Journal of Animal Ecology 37; 641- 674. 1974. ‘Nature reserves and wildlife’ (Heinemann Educational Books: London). 1975a. Habitat selection by spiders in man-made environments, Proceedings of the 6th Interna- tional Arachnological Congress, Amsterdam, 1974: 53-67. 1975b. The effects of human trampling on the fauna of grassland litter. Biological Conservation 7: 255-274. 1978. Ecological strategies in spiders, including some characteristics of species in pioneer and mature habitats. Symposia of the Zoological Society of London 42: 109-123. DUFFEY, E. & GREEN, M.B. 1975. A linyphiid spider biting workers on a sewage-treatment plant. Bul- letin of British Arachnological Society 3: 130- 131, EDWARDS, C.A., BUTLER, C.G. & LOFTY, J.R. 1975. The invertebrate fauna of the Parks Grass plots, II. Surface fauna. Report Rothamsted Ex- perimental Station, 1975(2): 63-89. JANSSEN, M. & BAERT, L. 1987. ‘Catalogus van de Spinnen van Belgie, Deel IV, Salticidae’. (Studiedocumenten No. 43, Koninklijk Belgisch Instituut voor Natuurwetenschappen: Brussel). 502 JOCQUE, R. 1973. Spider fauna of adjacent woodland areas with different humus types. Biologisches Jahrbuch Dodonaea 41: 153-178. KEKENBOSCH, J., BOSMANS, R. & BAERT, L. 1977. ‘Liste des araignées de la faune de Belgique’, (Institut Royal des Sciences Naturelles de Belgique: Bruxelles), KESSLER, A. 1973. A comparative study of the production of eggs in eight Pardosa species in the field (Araneidae, Lycosidae). Tijdschrift voor En- tomologie 116: 23-41. LOCKET, G.H. & MILLIDGE, A.F. 1953. ‘British spiders’. 2 vols, (Ray Society: London). LOCKET, G.H., MILLIDGE, A.F. & MERRETT, P. 1974. ‘British spiders, Vol. III’, (Ray Society: London). MEIJER, J. 1977. The immigration of spiders (Araneidae) into a new polder. Ecological En- tomology 2; 81-90, MOUNTFORD, M.D. 1962. An index of similarity and its application to classificatory problems. Pp. 43- 50. In Murphy, P.W. (ed.). ‘Progress in soil zoology’, (Butterworths: London). PROSZYNSKI, J. 1978. Distributional patterns of the Palaearctic Salticidae (Araneae). 335-43. In Mur- phy, P.W. (ed.) ‘Symposia of the Zoological Society of London No. 42, Arachnology’, RANSY, M. & BAERT, L. 1985, ‘Catalogus van de Spinnen van Belgie, Deel Il. De Cribellatae’, (Studiedocumenten No. 25, Koninklijk Belgisch Tnstituul voor Natuurwetenschappen: Brussel). 1987a. Catalogue des araignécs de Belgique, Pt 3. Les Araneidae. Documents de Travail No. 36. (Institut Royal des Sciences Naturelles de Belgi- que: Bruxelles). 1987b. Catalogue des araignées de Belgique, Pt 5. Anyphaenidae, Argyronetidae, Atypidae, Dys- deridae, Mimetidac, Nesticidae, Oonopidae, MEMOIRS OF THE QUEENSLAND MUSEUM Oxyopidae, Pholcidae, Pisauridae, Scytodidae, Segestriidae, Eusparassidae, Zodariidae, Zoridae, Documents de Travail No. 46 (Institut Royal des Sciences Naturelles de Belgique: Bruxelles). RANSY, M., KEKENBOSCH, J. & BAERT, L. 1990. Catalogue des araignées de Belgique, Pt 6, Clubionidae et Liocranidae. Documents de Travail No. 57. (Institut Royal des Sciences Naturelles de Belgiques: Bruxelles). RATCLIFFE, D. A. (ed.). 1977. Spiders. Pp. 95-101. in ‘A nature conservation review, Vol. I’. (Cambridge University Press: Cambridge). RICHTER, C.J.J. 1970. Aerial dispersal in relation to habitat in eight wolf spider species (Pardosa, Araneae, Lycosidae). Oecologia, Berlin 5: 200- 214, ROBERTS, M. J. 1985-87, ‘The spiders of Great Britain and Ireland’, 3 vols. (Harley Books: Colchester). SCHAEFER, M. & TISCHLER, W. 1983. ‘Warterbiicher der Biologie; Oekologie’. (Gustav Fischer: Jena). SNAZELL, R. 1982. Habitat preferences of some spiders on heathland in southern England. Bulletin of the British Arachnological Society 5: 352-360. UETZ, G.W. 1991. Habitat structure and spider forag- ing. Pp. 325-348. In Bell, 8.S., McCoy, E. D, and Mushinsky, H.R. (eds). ‘Habitat structure, the physical arrangement of objects in space’. (Chap- man and Hall: London). VAN WINGERDEN, W. 1977. ‘Population dynamics of Erigone arctica (White) (Araneae, Linyphiidae)’, Doctoral thesis, Free University of Amsterdam. WEBB, N. R. 199). Changes on the heathlands of Dorset, England between 1978 and 1987. Biologi- cal Conservation 51: 273-286, THE DEVELOPMENT OF THE ASYMMETRICAL WEB OF NEPHILENGYS CRUENTATA (FABRICIUS) JANET EDMUNDS Edmunds, J, 1993 11 11: The development of the asymmetrical web of Nephilengyscrueniata Rateient), Memoirs of the Queensland Museum 33(2): 503-506. Brisbane. ISSN 0079- In the field, young Nephilengys cruentata (Fabricius) remain on the barrier threads of their mother’s web for about ten days, before moulting. Some do not initially disperse far, and may even remain on the barrier threads to build their first web, These first webs are complete orbs, As the spiderlings grow the hub of the web is spun approximately three quarters of the way up the web; later there are no spirals above the hub. At this stage some spiders join the hub to the barrier, forming a ‘tent’ under which the spider rests. The true retreat, of a tube that is closed at the end away from the hub, develops gradually as the spiders grow further, ONephilengys, web development, evolution of webs. Janet Edmunds, Mill House, Mill Lane, Goosnargh, Preston PR3 2UX, United Kingdom; 12 November, 1992. Nephilengys cruentata (Fabricius) is common throughout tropical Africa. In Ghana it lives in savanna and forest edge areas. Under natural conditions it attaches its web to trees, but it has frequently adapted to attaching it to dwellings. It was very common at Legon in such situations. The adult female is large but the male is much smaller. The webs of larger spiders are usually a roughly triangular partial orb. The hub is at the Upper apex, where there is a cylindrical retreat, closed at the end away from the hub. There is an extensive barrier above and behind the viscid web; the main attachment between the two is at the hub, The hub and retreat are often in the angle between a wall and the ceiling or overhang. This paper presents data on the shape of the web of N. cruentata from the earliest instars to adults. METHODS Spiders of all ages were observed living on the verandahs of a private dwelling and of the Zool- ogy Department at Legon, but it was not possible to follow individual spiders in the field or cap- tivity. Web size and length of the first leg of cach spider were measured, although the relation be- tween spider size and instars was not determined. The vertical asymmetry, lateral asymmetry and shape (circularity) of the web were determined from the ratios of vertical radii, horizontal radii and the two diameters respectively, all measured to the nearest 5mm; N for all figs is given in Table l. RESULTS The cocoon ts laid clese to the web, often on a wall or ceiling. When the spiderlings emerge, they remain close to where they have emerged in a tight bunch on the barrier web for about ten days, spinning extra irregular threads. After the first post emergence moult, they disperse, but many remain close to the mother’s web, some even building their first catching web in the threads of the barner web. When the spiders are grouped into different size classes based on leg 1] length, the extent of the web below the hub increases with each succes- Leg Length mn FIG. 1. Changes in vertical asymmetry in webs of N. cruentaia with different leg lengths, At top: ratio of upper to lower radius = 0; Between centre and top: ratio of upper to lower radius >0 <1; Central: ratio of upper to lower radius = 1. 504 Leg length FIG, 2. Changes in lateral asymmetry in webs of N. cruentata with different leg lengths. At side: ratio of two horizontal radii = 0; Between centre and side: ratio of two horizontal radii >0 <1; Central: ratio of two horizontal radii = 1. sive class, while that above the hub increases slightly before decreasing to zero (Table 1), The vertical asymmetry increases with size (Fig. 1): spiders with leg 1 <6mm spin complete orbs. As they grow, less web is spun above the hub, so that the hub is then about three quarters of the way up the web. Larger spiders, with leg 1 >19mm have no web above the hub. Because of the difficulty in following individual spiders, the time span over which these web changes occurred is not known. Early webs are symmetrical laterally (Fig. 2), but webs of larger spiders show greater variation and may be markedly asymmetrical laterally; at the extreme the hub is completely to one side. Some early webs are also circular or nearly so (Fig. 3), however very few webs of spiders with leg 1 > 6mm have the vertical and horizontal diameters of the same size. During these changes in the proportions of the TABLE 1. Body size and web dimensions (in mm) in different size classes (based on leg 1 length) of Nephilengys cruentata. Leg 1 length <6 Body size_ <3.5 N Hub-web top:mean range Hub-web bottom: mean range | 25-50 45-170 140-260 4 Web Width: mean 73.8 117.9 177.4 431.1 range | 70-90 80-180 | 80-290 | 240-850 MEMOIRS OF THE QUEENSLAND MUSEUM = Z 80 a ee 70 === 60 == 50 40 % <6 mm = : -30 = ‘20 7-12 mm 10 13-18 mm ? Leg length Longer >19 mm ¥ than Circular wide Wider than long Web shape FIG, 3. Changes in shape in webs of N. cruentata with different leg lengths. Longer than wide: vertical diameter > horizontal diameter; Central: vertical diameter = horizontal diameter; Wider than long: vertical diameter < horizontal diameter. viscid web, the barrier increases (Fig. 4). The very first webs have no barrier or just a few threads, which are attached to the orb at only a few points. But over some days more threads are added, until the barrier is a fairly dense cone shaped tangle behind the orb, and more firmly fixed to the web. Small pellets of detritus, similar in size and shape to the spiderling and of the same pale grey colour, usually occur in the barrier (Edmunds and Edmunds, 1986). These may deflect attacks of potential predators. The development of the retreat increases with the size of the spider (Fig. 5). Spiders with the hub 80- 70- 60 Pp % 50-4 == ‘ Ad = IF Barrier 40-4 = 30-4 = 20-+“| nt | ees 0 a (=F Complete ebeyries aa & 7 Few threads tied i: None 13-18 mm Leg length >19mm FIG. 4. Development of barrier in webs of N. cruentata with different leg lengths. WEB OF NEPHILENGYS 13-48 mm = 2 Legiength 4am “\| > 7 i 1 F e e 2 2 3 Retreat FIG. 5. Development of retreat in webs of N_crientata with different leg Jengths. at the centre or part of the way up the web rest at the web hub and there is no retreat. When the hub is huilt at or very close to the apex, the first stages of a retreat are formed as a denser group of threads within the barrier close to the hub, As more threads are- added, this becomes a roof-like tent between the hub and the barrier, or some- times an open ended tube. Spiders with leg 1 >19mm normally hada closed tubular retreai, like an adult. Early webs are very fine, and it is not easy to see the details of the individual threads. However, a complete web appears to be spun in one opera- tion, unlike larger webs which are spun in two or more sections on different days. The temporary spiral does not appear to be left up, though more detailed observations would be needed to confirm this. Larger spiders leave the temporary spiral in the finished web. DISCUSSION The webs of most adult female Nephilinae are not typical orbs. Most Nephila species build in- complete orbs, with the hub near the top (Robin- son and Robinson, 1973, figs 2, 20; pers. obs.). However, unlike Nephilengys, there are threads above the hub, including in some instances a few sticky spirals. In Nephila plumipes large, probab- ly mature, females were seen in Brisbane, Australia, that had several sticky radii above the hub. However, in at least some individuals, these appeared to have been laid as pendulum turns, rather than complete spirals (pers. obs.). Nephila does not build a retreat and the spider rests at the SS hub. Like Nephilengys, there are barrier webs, though on both sides, and often above the orb, These are ive and probably also defensive (Robinson and Robinson, 1973). Herennia or- natissima (Doleschall) constructs a very long web, with almost parallel sides (Robinson and Lubin, 1979). The spider sits in a cup-shaped depression of dense silk that forms the hub. It is towards the top of the web. though there are several sticky spirals above it. The spider has no barrier web, but as it builds very close to tree trunks, tt would be difficult to find a place to build one. Larger juvenile Nephilinae build webs like the adults, and a few observations have been publish- ed on the very early webs. The first webs of Nephila clavipes (Linnaeus) are circular (Com- stock, 1948; Levi and Levi, 1968). Brown amd Christenson (1983) give measurements of the webs of N. clavipes spiderlings between 2 aml 9mm body length. The webs show an increase in vertical asymmetry as they grow. However, uti- like Nephilengys cruentata, even the instars thal spin the first catching webs had the hub ap- proximately two thirds of the way up the web, Both species seem to spin the hub at the top of the web when they reach a similar size. Webs with spirals above the hub are spun by juvenile Nephila maculata (Fabricius) (Robinson und Robinson, 1973, figs 5, 6), and possibly by Nephila senegalensis (Walckenaer) (Clausen, 1987). The webs of juvenile Herennia ornatis- sima (Robinson and Lubin, 1979) are also more like a complete orb. The fact that the earliest webs of at least some species of Nephilinae are complete orbs indicates that the orb is a primitive characteristic in them, and that the incomplete orbs of the larger spiders are derived, There are other spiders which havea highly modified orb-web, but build a more com- plete orb as a juvenile. Spiders of the genus Scoloderus build extremely elongated inverted ladder webs, with the hub towards the base. The juveniles of Scoloderus mberculifer O.P.- Cambridge have webs that are far less distorted (Eberhard, 1975). However, even the smallest S. cordata (Taczanowski) have elongated ladders (Stowe, 1978). In Araneus atrihastulus from New Zealand, which builds a web that is elongated both above and below the hub, some of the proportions of juvenile webs are less extreme (Forster and Forster, 1985). It would be interest- ing to find the very early Webs of other spiders with atypical webs, such as that of the spider that built the ladder web observed by Robinson anc Robinson (1972) in New Guinea, now identified as close to Tylorida (Eberhard, )990b). Other aspects of web construction and use may be more derived in adults than in juveniles, such as the angle of the spring line and resting position of the spider in Epeirotypus sp. from Costa Rica (Eber- hard, 1986). However, in the west African Pararaneus cyrtoscapus (Pocock), the conical horizontal webs of juveniles are more derived than the planar vertical of adult females (Ed- munds, 1978). If it is confirmed that young Nepfilengys crueniata build webs in one piece and destray temporary spirals. then the adult behaviour of leaving the temporary spirals in place is presumably alsoa secondary modification. There gre other characteristics of the webs of Nephilinae that are derived. Despite their size, the webs of adults have a finer mesh compared to some other orb Weavers (personal observation). Eberhard (1982, 1990) concludes that some characteristics of the web building behaviour of Nephila clavipes, such as the unique method of laying the sticky spiral, are an adaptation to spin- ning a tightly meshed web, even though other aspects (e.g. frame construction) are pnmilive. Levi (1986), Eberhard (1990a) and Coddington (1990) classify the Nephilinae with the Metinae and tetragnathids, rather than with Araneus and its relatives, The derived nature of the partial orb of the larger Nephilinae would be consistent with this classification. ACKNOWLEDGEMENTS I would like to thank Prof D.W. Ewer for the use of Facilities while working at the Univensity of Ghana, ant Malcolm Edmunes for construc- tive comments, LITERATURE CITED BROWN, S.G, & CHRISTENSON T\E. L983. The relationships between web parameters and spiderling predatory behavior in the orb-weaver Nephila clavipes, Zeitschrift fiir Tierpsychologie 63; 241-250, CLALSEN, 1.4.S. 1987. On the biology and behaviour of Nephila senegalensis senegalensis (Walck- enaer, |837), Bulletin of the British Arachnologi- cal Society 7: 147-150. CODDINGTON, FA. 1990. Ontogeny and homology in the male palpus of orb- weaving spiders and their relatives, with comments on phylogeny (Araneoclada: Araneoidea, Deinopoidea). Smith- sonian Contributions to Zoolugy 496: 1-52. MEMOIRS OF THE QUEENSLAND MUSEUM COMSTOCK, J.H. 1948. ‘The spider book”. Revised and edited hy W.J. Gertsch (Comstock Publish- ing: Ithaca). EBERHARD, W.G. 1975. The ‘inverted ladder’ orb web of Scvloderus sp, and the intermediate orb of Eustala (?) sp. (Araneae: Araneidac). Journal of Natural Histary 9: 93- 106. 1982. Behavioral characters for the higher clas- sification of orb-weaving spiders. Byolution 36: 1067-1095, 1986. Ontogenetic changes in the web of Epeirotypus sp. (Araneae, Theridiosomatidac). Joumal of Arachnology 14: 125-128. 1990a. Early stages of orb construction by Philoponella vicina, Leucauge mariana, and Nephila clavipes (Araneae, Uloboridae and Tetragnathidae), and their phylogenetic implica- Hons. Journal of Arachnology 18: 205-234. 1990b. Function and phylogeny of spiders webs. Annual Review of Ecology and Systematics 21: 441-372. EDMUNDS, J. 1978. The web of Paranens [sic] eyr- toscapus (Pocock 1899) (Araneae: Araneidae) in Ghana. Bulletin of the British Arachnological Society 4: 191-196. EDMUNDS, J.& EDMUNDS, M. 1986, The defensive mechanisms of orb weavers (Araneac: Araneidac) in Ghana, West Africa. Pp. 73-89. In Eberhard, W.G., Lubin, ¥.D. and Robinson, M,H. (eds). Proceedings of the Ninth Intemational Congress of Arachnology, Panama (Smithsonian Institu- tion: Washington D.C,), FORSTER, L.M. & FORSTER, R.R, 1985, A deriva- tive of the orb web and its evolutionary sig- nificance. New Zealand Journal of Zoology 12: 455-465. LEVI, H.W. 1986. The neotropical orb-weaver genera Chrysometa and Homalemera (Araneae: Tetrag- nathidae). Bulletin of the Museum of Comparative Zoology 151: 91-215. LEVI, H.W, & LEVI, L.R. 1968, ‘A guide to spiders and their kin’. (Golden Press: New York). 160pp. ROBINSON, M.H, & LUBIN, Y.D, 1979. Specialists and generalists: the ecology and behavior of some web-building spiders from Papua New Guinea. Pacific Insects 21; 97-132, ROBINSON, M.H. & ROBINSON, B. 1972. The siruc- ture, possible function and origin of the remark- able ladder-web built by a New Guinea orb-web spider (Araneae: Arancidae). Journal of Natural History 6: 687-694. 1973. Ecology and behavior of the giant wood spider Nephila maculata (Fabricius) in New uinea. Smithsonian Contributions to Zoology 149: 1-76. STOWE, M.K. 1978. Observations of two nocturnal orbweayers that build specialized webs: Scaloderus cordatus wnd Wivia ectypa (Araneae; Araneidac), Journal of Arachnology G: 141-146. DOES MIMICRY OF ANTS REDUCE PREDATION BY WASPS ON SALTICID SPIDERS? MALCOLM EDMUNDS Edmunds, M. 1993 11 11: Does mimicry of ants reduce predation by wasps on salticid spiders? Memoirs of the Queensland Museum 33(2); 507-512. Brisbane. ISSN 0079-8835. A common predator of spiders at Legon, Ghana, is the wasp Pison xanthopus, 96% of whose prey were salticids. The data from cells built by 31 wasps containing over 800 spiders are used to examine whether mimicry of ants gives protection against Pison, Comparison of salucids in wasp cells with those found on nearby vegetation shows that fewer ant mimics (Myrmarachne spp.) are taken than one would expect if wasps were capturing salticids in proportion to their occurrence, but also that some individual wasps specialize in capturing Myrmarachne. Implications for the searching image hypothesis are discussed. OBaresian mimicry, ant-mimicry, Salticidae, predation, search image, Pison, Myrmarachne. Malcolm Edmunds, Department of Applied Biology, University of Central Lancashire, Preston PRI 2HE, United Kingdom, 12 November, 1992. Ant mimicry has evolved in several spider fam- ilies, e.g. Salticidae, Clubionidae, Thomisidae, Aphantochilidae and Theridiidae (Hingston, 1927; Mathew, 1954; Reiskind and Levi, 1967; Reiskind, 1977; Edmunds, 1974, 1978; Wanless, 1978; Oliveira and Sazima, 1984, 1985; Oliveira, 1988). Some of the most precise morphological and behavioural resemblances to ants occur in the sallicid genus Myrmarachne which is widespread in both the Old and New Worlds, especially in the tropics (Wanless, 1978). At Legon, Ghana, three species of Mynnarachne are common, each one closely resembling one species of ant when it is full grown but a different ant species when it is immature (Edmunds, 1978). This mimicry could have two advantages for the spider: 1. It could deceive the ants and so enable the spider to creep up and prey on them. This is aggressive mimicry as may possibly occur in the thomisid Amtyciaea forticeps (Mathew, 1954), and is well documented for the aphantochilid Aphantochilus rogersi (Oliveira and Sazima, 1984); 2. It could deceive a predator into mistaking it for an ant which that particular predator does net eat, This is batesian mimicry, Myrmarachne do not normally attack ants, so there is no support for aggressive mimicry (Ed- munds, 1978; Wanless, 1978). Indeed whenever an ant comes near they use their acute eyesight and quick reactions to avoid contact. This stug- gests a danger of being killed if caught by the ants (Edmunds, 1978; Wanless, 1978), Direct evidence supporting batesian mimicry is sparse. Edmunds (1974, 1978) argued that because few insectivorous birds prey on ants, the ant mimics associated with them would also escape predda- tion. He further atienypted to show that ant- mimicking spiders are less often taken by the wasp Pison xanthopus than are other salticids, but there were rather little data available at that time. More recently, the American ant mimic Synageles occidentalis was found being preyed on much less than are non-mimicking salticids by the philodromid Tibellus eblengus, and the large salticid Phidippus clarus ignored or avoided Synageles and ants inexactly the same way, while continuing to attack non-mimicking salticids (Cutler, 1991) More data on the prey of Pison xanthopus are given here to test the theory that ant mimicry gives protection against spider-hunting wasps. MATERIAL Mud cells of Pisen xanthopus were collected from window frames at the University of Ghana, Legon, Ghana between 1969 and 1973. In- dividual wasps build from 1-6 cells inarow, Each cellis stocked with 5-10 paralysed salticid spiders und an egg is laid on one of these. The spiders were preserved in alcohol and identified, usually to genus or species. They were also classed as either good ant mimics (Myrnmarachne), poor ant mimies (Cosmephasis sp.) or non-mimics (other genera), Most of the spiders are now in the col- Jection of the Natural History Museum, London. Identification of the spiders was confirmed by F.R. Wanless, and the wasp was determined by the late Professor O.W., Richards, 308 taints AE [MyrmarachnefoenisexSimon | |_| [+ |+ |+ | Myrmarachne elongata Seombuhy | | |+ [+ | [+ | emracinelegen Wankss__1_{ fyrmaruchne avira Wanless Cosmaphasis sp. Non-mimics Husarivsadansont (Audouin) Schenkelio modesta Lessert Pseudictus sp, Other non-mimicking salticids TABLE I. Salticid spiders in five habitats at Legon, May-July 1973. RATIONALE If ant mimicry deceives wasps so that they do not capture ant-mimicking spiders as often as non-mimics, then the proportion of ant mimics to non-mimics should be lower in wasp cells than in the natura] environment. If wasps are not deceived then the proportion of ant mimics should be the same. The test of this hypothesis ts to compare the incidence of ant mimics in wasp cells with those found in the field, WHERE DOES PISON HUNT? First. the wasp’s hunting range must be estab- lished so that a random sample of salticids can be collected from the same place, Pixon is small, difficult to follow in flight, and was observed hunting on only a few occasions. Each time it was running and making short flights over leaves of shrubs. It was never observed on the ground or in grass, but as | spent more time examining shrubs than any other habitat, this is not conclusive. I therefore collected salticids from several dif- ferent habitats at Legon. If the species of spider MEMOIRS OF THE QUEENSLAND MUSEUM taken by wasps correspond with those found in one particular habitat then the wasps are probably hunting in that habitat. The habitats are: leaf litter; short, regularly cut grass; Jong grass and herbage; 1-3m high shrubs; and tree trunks. The spectrum of spiders in wasp cells is most similar to those found in shrubs and trees (Table 1), The canopy was not sampled but probably has a similar fauna. However, it is un- likely that the wasps were hunting in short grass, leaf litter or long Brass- RESULTS Sprmers tv Wasp CELLS AND ON SHRUBS Some variation in the numbers of spiders caught by each wasp (Table 2) is due to the different numbers of cells completed by the wasps when collected. Cells with full grown lar- vae OF pupae were ignored since the spiders in them were reduced to carapace cuticles, but cells with eggs or young larvae contained spiders that were intact and so are included, The spiders caught by each wasp came from 2-9 cells.e.g. on 3 Feb 1973, the first cell contained a pupa, the second a full grown larva, and the third had nine spiders but no egg. The wasp presumably was. killed before fully provisioning this cell, OF 872 spiders found, 837 were salticids (Table 2); 160 were ‘good’ ant mimics (i.e, Myr- marachne spp.), judged by the human eye, and a further 15 can be classed as poor (behavioural) ant mimics (i.e. Cosmephasis spp.). In 1973, every shrub in Zoology (twice) and in Botany (once) was searched {see Edmunds, 1978). All salticids found were scored as either a good mimic, a poor mimic or a non-mimic. The dif- ferences between types are highly significant (x2) =49.04, p<0.001; Fig. 1). Pisenclearly take significantly fewer good ant mimics than they do poor Mimics or non-mimics compared with their incidences in the environment. However, wasps searching by running quickly over vegetation are unlikely to find spiders rest- ing in their retreats beneath or between leaves. So perhaps the comparison should be made between the numbers of spiders in wasp cells and the numbers foraging on leaves (excluding those in retreats). These figures are also given in the upper part of Fig. 1 (the black bars only): 61.9% of spiders on shrubs were good mimics compared with 19.1% in wasp cells. This too is highly significant, again indicating that wasps take many fewer good mimics than poor or non-mimics (x*(2) = 64.15, p<0.001). The proportion of poor WASP PREDATION ON ANT-MIMICKING SALTICIDS % InShrubs 60 In retreats in the open 662 160 Good mimics Non- mimics Poor mimics FIG, 1, Comparison of good, poor and non-ant mimick- ing Salticids on shrubs and in cells of Pison xan- thopus. mimics taken by wasps is not significantly dif- ferent from that of the non-mimics, so in the analysis that follows the poor (behavioural) mimic Cosmophasis is treated as a non-mimic. SPATIAL OR SEASONAL VARIATION These comparisons are of spiders on shrubs in February and May 1973 with spiders in wasp cells collected over 3.5 years. The relative numbers of Myrmarachne and of other salticids vary throughout the year and over different parts of the University campus, and this may account for the differences in proportions of spider prey taken by wasps. Evidence against this possibility is (1) that there was no significant difference in the relative numbers of Myrmarachne and of other salticids collected on shrubs in February and in May 1973 (Edmunds, 1978); (2) that the three wasp cells (taken 22 Jan- 3 Feb 1973 ) from close to where the shrubs were surveyed had between them eight Myrmarachne and 54 other salticids compared with 24 Myrmarachne and 26 other salticids on the shrubs on Feb 2; this difference is highly significant (y~1 = 15.0, p<0.001); and (3) that the data (Table 2 ) show no clear evidence of spiders occurring at particular sites or in certain seasons, So, while there may be some variation in spider species at different times and places at Legon, such variation is unlikely to account for the very different numbers. of salticids taken by wasps assuming that they take different species in proportion to their frequency in the population. No Wasps Near DANGEROUS ANTS Most Myrmarachne taken by Pison were black and identified as M. legon and M. elongata (Wan- less, 1978) but some immature specimens could not be identified. Only one specimen of the very common M. foenisex, in a total of 160 Myr- marachne, was taken, It was a juvenile whose body was red-brown and black (Edmunds, 1978, Fig. L), quite unlike Oecophylla, but very similar to the smaller ant Crematogastercastanea which only lives close to Oecophylla (Edmunds, 1978). M.foenisex closely associates with the aggressive red weaver ant Oecophylla longinoda, of similar colour. Adult M. foenisex are probably too large for Pison to attack, but since it captures many young black Myrmarachne one might expect it to tuke young M. foentsex as well. Young M, legun are quite similar to young M. foenisex, but they do not associate with Oecophylla nor with C. castanea. Many young M. legon but very few M. foenisex were taken by Pison. Hence, Pixon probably avoids hunting on plants overrun by Oecophylla, If Pison does not hunt on plants with Oecophyl- la, then salticids found with these ants need to be omitted from the comparison of ant mimics and non-mimics on shrubs and in wasp cells (Table 3). Of salticids on shrubs, 49% are good ant mimics compared with 19% in wasp cells, This difference is highly significant, and remains so if spiders in retreats are excluded (p <0.001). Wasps clearly take fewer Myrmarachne than one would predict if they caught them in propor- tion to their occurrence in the environment. This is therefore good evidence for the defensive value of ant mimicry against predation by Prson. Non-ant mimicking spiders reo | 8 te | 1 1 bet 1 1 11 1 1 ei asa jam fs |_| jst {was {_|—_fa Sane issee 15 fy) pF a] | | 778 fusser || foe 1 2m hsser || | lag [tr fs [| TT hh hist zoos | fe 11 | 1. 1 1 | b | a) a Ps a et fe Pe et Ft tf MEMOIRS OF THE QUEENSLAND MUSEUM |__| wasps who between them took only eight Myr- marachne out of 73 spiders (11%), while it failed to protect them from the fourth wasp which took 34 Myrmarachne out of 46 prey (74%). Overall, 25 in- dividual wasps took only 38 Myrmarachne out of 693 spiders (5.5%), in- dicating that they had been deceived by the mimicry. The other seven wasps took 122 Myrmarachne out of 179 spiders (68.2%) indicating that they had overcome the defence of mimicry to the extent that they preyed almost ex- clusively on ant mimics (a wasp on 6 July 1972 took 25 Myrmarachne and no pi Sal = jini7z [win [5] [a6 | |r| Tae a M72 Zool. tare Fea 16.1.73 [Hi | |_| other spiders, while in the other six wasps Myr- marachne taken were az foo a | 1 iy Shs Seth sae | Te 2155 [att | rss ssee tbs |_| fas a 225.73 TABLE 2. Spiders in cells of Pison xanthopus at Legon, Ghana, 1969-1973. Key to Places al University of Ghana, Legon: Faculty of Agriculture, Agric.; Depart. of Botany, Bot.; Institute of Statistical, Social and Economic Research, ISSER; 36 Legon Hill, Hill; Depart. of Mathematics, Maths; Depart, of Zoology, Zool. - 17 Thomisidae, 6 Theridiidae, 5 Clubionidae, 2 Oxyopidae, 1 Araneidae, | Gnaphosidae. Taxon head is abbreviated in order: My, Mynmarachne sp.; Co, Cosmophasis sp.; Ps, Pseudicius sp Rh, Rhene sp.; Te, Telamonia sp.; Me, Menemerus sp.; Vi, Viciria sp., So, Sonoita lighrfooit; Th, Thyene sp.; Sa, Saitis sp., Mo, Mogrus sp.; Fi, Fissident sp.; Os, other Salticidae; Of, other spider families. Selenopidae, | Philodromidae. 2 Oxyopidae, * - Do InpivipuaL Wasps Hunt Speciric Prey? All wasps do not take a similar spectrum of spiders, but each individual preys on one or two species of spider (Table 2). Thus the first wasp in the table preyed on Rhene sp., the second and third on Pseudicius sp. and the fourth on black species of Myrmarachne, Ant mimicry was ob- viously of defensive value against the first three never less than 45%), For the poor ant mimic, Cosmophasis, the 15 spiders taken by wasps (Table 2) represent 1.7% of all salticids taken, or 2.1% excluding Mynmarachne. This is less than their rela- tive frequency on shmbs (2.4% of all spiders or 5.1% excluding Myr- marachne), but the dif- ferences are not sig- nificant. However, one wasp (on 5.2.72) caught }1 Cosmophasis while all other wasps very rarely took them, Therefore, even poor mimicry of ants ap- pears to give some protec- tion against most wasps, but occasionally a wasp will specialize on this species, just as other wasps do with Myr- marachne. HUNTING BY THE SEARCHING IMAGE MeTHOD ‘The term searching image was used to describe the way in which tits (Paridae) collect caterpillars for their young: each bird tends to bring insects WASP PREDATION ON ANT-MIMICKING SALTICIDS TABLE 3. Percentages of Myrmarachne (Myrm) and other sallicids on shrubs at Legon, and in cells of Pison xanthopus. Pigures in brackets are numbers and a found in open (i.e. notin ee Source of spiders Seite 9 een saa jos |b 8) 53(41) |49.1 (54.5) of predominantly a single species for several days and then to abruptly switch to another species (Tinbergen, 1960). Tinbergen hypothesized that the birds recognised caterpillars by particular characters which they ‘assimilated in a kind of i He process’ and that in their search for prey they looked for these particular characters. Later authors have used the words “searching image” and ‘search image’ interchangeably, but its definition has been refined following Croze (1970), Dawkins (1971), Krebs (1973), Lawrence and Allen (1983) and Guilford and Dawkins (1987). Itas now generally understood to mean a perceptual change in a predator that temporarily increases 38 ability to detect particular cryptic prey which it has recently encountered. Search- ing image needs to be distinguised from various other types of preference that predators may show for particular prey (Krebs, 1973; Lawrence and Allen, 1983), so it is probable that the behaviour observed by Tinbergen which he called hunting by means of a ‘specific searching image’ would loday not be considered a proven example of searching image behaviour. Individual Pison xanthopus clearly concentrate on one of a few species of prey; is this because it hunts using a searching image or by some other method? In a recent critique of the search image concept Guilford and Dawkins (1987, 1988a,b) argue that all studies purporting to demonstrate searching images can actually be explained better in terms of variation in search rate. They make iwo predictions which can distinguish between the two hypotheses. First, the search rate hypothesis predicts that mimetic prey should take longer to find than non-mimics, so wasps that have learned to find them will slow down their search rate. The searching image hypothesis maukes no such prediction. Second, the searching image hypothesis predpets thal because of percep- tual specialization, Wasps concentrating on one type of prey will ignore others, The search rate Shrubs-omilling M4, foenisex & all spiders with ants Oecoplryilu S11 hypothesis makes no prediction about concentra- tion on one prey interfering with finding other prey. These observations do not explicitly test either prediction, but I consider that Pisen is nol hunting by adjusting ils search rate because cif- ferent wasps concentrate on different prey imply- ing that capture of several prey of one species interferes with capture of other species. The two wasps at ISSER on 5th and 6th of July 1972 took very different prey. If they had been hunting simply with different search rates then the first wasp should have taken some Myrmtarachne while the second should have taken some Pseudicius. This total concentration on one species of prey is noteasy to explain on the search rate hypothests. If Pisen is not capturing prey by adjusting its search rate, there are at least three other hunting inethoxs that might result in the concentration on particular species of prey shown in Table 2;- 1. Wasps might have some sort of preference for one prey rather than another, This is unlikely if the preference is based on taste because the wasps sting bul do not eat the prey, 2. Wasps could be searching in different places;- a. Individual wasps might search in different microhabitats. If each species of spider lives in a slightly different microhabitat on the shrubs then individual wasps could catch different species of spider. Evidence in favour of this is the wasp on 18 Mar 1972 which concentrated on thomisid and other non-salticid spiders. Because it initially caught some of these spiders it is reasonable fo suppose that it learned to hunt in particular areas or in a particular way such that it continued to catch these spiders instead of salticids, b. Wasps might search in one area before going on to another. If spiders are clumped instead of being randomly spaced, then individual wasps hunting in the same general area could capture different species of spider. [ often found two or three spiders of one species on a shrub so the distribution is clumped rather than random. How- ever, there is no exclusion of one species by another, and the clumping may simply be of recently mated pairs or of parents with young that have failed to disperse. This impression has not been quantified, but T consider it unlikely that it could explain the extreme specialization on one species (Table 2). 3. The wasps may have a perceptual searching image as implied by Croze (1970). Wasps of other genera can Jearn the configuration of landmarks near their hurrows (see Tinbergen, 1958), and this presumably involves some per- ceptual memory not unlike that in ourselves when we search for something with a particular image in our mind. Itis unclear which of the above methods of prey capture or if another method (e.2., Krebs, 1973) is involved, But certainly some such behaviour occurs both in Pison and in other wasps, e,g- the sphere Chalybion fuscipenne (J. Edmunds, 1990). CONCLUSIONS Clearly, ant-mimicking spiders are common, more so than non-mimics in some habitats. Ant mimicry may give protection against wasps such as Sceliphron which prey on spiders of vanous families (Edmunds, 1974: J. Edmunds, 1990). The results confirm the suggestion from 4 preliminary, less rigorous study (Edmunds, 1974), that ant mimicry is of protective value against the specialist predator Pison xanthopus. The evidence that behavioural ant mimicry protects Cosmophasis against Pisen is not con- clusive; il may be protective against other'wasps or against birds. Wanless (1978) and Curtis (1988) have evidence that spiders of this genus prey on ants, so this mimicry could also be ag- gressive rather than defensive in function. ACKNOWLEDGEMENTS I am grateful to Fred Wanless for help with identification of the salticids, Paul Hillyard for identifying the other spiders, and Janet Edmunds for critically reading the papec. LITERATURE CITED CROZE, H. 1970. Searching image in carrion crows. + a aaa fiir Tierpsychologie, Supplement 5: |- CURTIS, B.A. 1988. Do ant-mimicking Cosmophasis prey on their Camponotus models? Cimbebasia (Windhock) 10: 67-70. CUTLER, B. 1991. Reduced predation on the antlike jumping spider Synageles occidentalis (Araneae: Salticidae), Journal of Insect Behavior 4; 401-407. DAWKINS, M. 1971. Perceptual changes in chicks: another look at the ‘search image’ concept. Animal Behaviour 19: 566-574. EDMUNDS, J. 1990. Wasp predation on orb web MEMOIRS OF THE QUEENSLAND MUSEUM spiders (Araneidac) in Ghana, Acta Zoologica Fennica 190: 117-122. EDMUNDS, M. 1974. ‘Defence in animals: a survey of anti-predator defences’. (Longman: London), 357 Pp. 1978. On the association between Myrmarachne spp. (Salticidae) and ants. Bulletin of the British Asachnological Society 4: 149-160. GUILFORD, T, & DAWKINS, M.S. 1987, Search images not proven: a reappraisal of recent evidence, Animal Behaviour 35: 1838-1845. 1988a. Search image versus search rale: a reply to Lawrence, Animal Behayiour 37: 160-162, 1988b. Search image versus search rate: two dif- ferent ways to enhance prey capture, Animal Behaviour 37: 163-165. HINGSTON, R.W.G. 1927. Field observations on spider mimics. Proceedings of the Zoological Society of London 56: 841-858. KREBS J.R. 1973. Behavioural aspects of predation, Pp, 73-111. In Bateson, P.P.G. and Klopfer, P.H. (eds) ‘Perspectives in ethology, Yol. 1’, (Plenum Press; London). LAWRENCE, B.S, & ALLEN, J.A. 1983. On the term ‘search image”, Oikos 40; 313-314, MATHEW, A.P. 1954, Observations on the habits of two spider mimics of the ted ant, Oecaphylla smaragdina (Fabr.). Journal of the Bombay Natural History Society 52; 249-263. OLIVEIRA, P.S_ 1988, Ant-mimicry in some Brazilian sallicid and clubionid spiders (Araneae: Sal- ticidae, Clubionidae). Biological Journal of the Linnean Society 33; 1-15. OLIVEIRA, P.S. & SAZIMA L., 1984. The adaptive bases of anit-mimicry in a neotropical aphan- tochilid spider (Araneae: Aphantochilidae). Biological Journal of the Linnean Society 22: 145-155. 1985, Ant-hunting behaviour in spiders with em- phasis on Strophius nigricans (Thomisidac). Bul- letin of the British Arachnological Society 6: 309-312. REISKIND, J. 1977. Ant-mimicry in Panamanian clubionid and salticid spiders (Arancae: Clubionidae, Salicidae). Biotropica 9: 1-8. REISKIND, J. & LEVI, H.W, 1967, Anatea, an ant- mimicking theridiid spider from New Caledonia (Araneae: Thendiidae), Psyche 74; 20-23. TINBERGEN, L, 1960. The natural contro! of insecis in pine woods. |. Factors influencing the intensity of predation by songhirds. Archives Néerlandaises de Zoologie 13: 265-343. TINBERGEN, N, 1958, ‘Curious naturalists’. (Country Life; London), 280 pp. WANLESS, F.R. 1978, A revision of the spider genera Belippo and Mynnarachne (Araneae: Salticidae) in the Ethiopian region. Bulletin of the British Muscum (Natural History) (Zoology) 33: 1-139, ABUNDANCE AND STRUCTURE OF FOSSORIAL SPIDER POPULATIONS PETER G, FAIRWEATHER Fairweather, P.G. 1993 11 11: Abundance and structure of fossorial spider populations. Memoirs of the Queensland Museum 33(2); 513-518. Brisbane. ISSN 0079-8835. Preliminary findings from an ecological study of large fossorial spiders, especially 5 a made in two locations in eastern New South Wales are given. The abundance of burrowing spiders was assessed in eight habitats: dry sclerophyll forests on sandstone and shale substrata, wet sclerophyll forests on sandstone, pastures, suburban gardens, pine windbreaks along roadside verges, coastal cliffs, and coastal swamps, The spiders included several species of Lycosidae, two Idiopidae and one Hexathelidac. Each species was restricted in its range of habitats and dominated the burrowing spider assemblage in only one or two habitats. The population stracture of burrow sizes is descnbed and compared for dense populations.[Araneae, Idiopidae, Hexathelidae, Lycosidae, ecolagy, burrowing, sampling, distributions, habitats, size frequencies. Peter G. Fairweather, Graduate School af the Envirarsnent, Macquarie University, New South Wales, 2109 Australia; 5 November, 1992, The field ecology of burrowing spiders in Aust- ralia has rarely used quantitative methods (but see Humphreys, 1988). Nor were field experimental manipulations used to test specific hypotheses, as in other branches of ecology (Underwood, 1990). These first quantitative observations of the abun- dance, ‘size structure and habitat associations of large burrowing spiders from two locations near Sydney are part of environmental studies of fun- nelweb and trapdoor spiders. The abundance, distribution and ecological in- teractions of fossorial spiders have been studied overseas in detail (see e.g. Buchlt, 1969; Laing, 1978; McQueen, 1983; Conley, 1985; Fernan- dez-Montraveta et @l., 1991; Miller & Miller, 1991). The general biology, systematics and evolution of Australian mygalomorph spiders have been studied (see Main, 1976; Raven, 1988). The few quantitative ecological studies from Australia focussed on arid habitats (e.g, Main, 1987: Kotzman, 1990), upland sites (e.g. Humphreys, 1976), or used pitfall trapping (e.g- Curry et al.. 1985), In contrast, this study was on the warm temperate coast of eastern Australia. METHODS Stupy Sites AND Hanitat Types Two locations near Sydney, New South Wales, and situated on Hawkesbury sandstone sub- stratum, were sampled. Galston (33°41°S, 150°21°E) is a semi-rural village that has become suburban since 1972 and retains pockets of bush. Study habitats were located at 170-210m altitude. Patonga (33°30’S, 151°15'E) is a coastal village on the Hawkesbury River estuary and surrounded by Brishane Waters National Park (Benson & Fullding, 1981). Study habitats were located ut 5-80m altitude. At each location, all sites were within 2km of each other. I sampled six habitats in each location, although only three were present in both Jocations (Table 1). SAMPLING AND ANALYSIS OF DATA The sampling, October 1991-March 1992. was non-destructive. Quadrats (0.25 m*°) were ran- domly placed and then searched for individual spiders, burrows and trapdoors. All rocks, logs and litter in each quadrat were overturned and searched. I counted spiders, burrows or webs of each species in each quadrat. | sampled 10) quad- rats in each of two sites in each habitat at cach location (n=240 quadrats in all). The paired sites were replicate patches of habitat at the same elevation, as similar as possible, at least 100m apart and 100-1000m? in area. Site boundaries were located randomly on habitat maps before sampling. Spatial variability in each habitat was assessed by comparing spider densities in each pair of sites. This design allowed a three-factor hierarchical ANOVA to examine the partitioning ef spider abundance (as density=no. per quadrat) among the fully nested factors of Location, Habitat with- in Locations and Site within Habitat (Sokal and Rohlf, 1981). ANOVAs were done after assump- tions were checked using Cochran's test for het- erogeneily of variances. Means and standard errors of spider densities were calculated for cach habitat and site. All statistical and graphical anal- yses were performed with SYSTAT Version 5 software (Wilkinson, 1990). 514 MEMOIRS OF THE QUEENSLAND MUSEUM Location | Habitat type Trees__|Shrubs_| Ground layer Galston__| Wet sclerophyl forest (WSF) sclerophyll forest (DSF) dense _|dense _| dense, rocks dense, moist | Atrax wolf D [sparse [dense _| | [Garden lawns (GL) __none_|few [grass | dense, d none M. rapax, wolf M. rapax, wolf Atrax wolf, M. rapax Shale turpentine forest (STF) | dense few | grass, logs Sparse, moist Pine road verge (PRV) pines few some grass deep, di M. gracilis wolf M. rapax little none Pasture none none __| grass i Patonga | Wetsclerophyll forest (WSF) |dense |dense | dense, rocks dense, moist Dry sclerophyll forest (DSF) | sparse little, rocks dense, d wolf, M. rapax, Atrax none wolf Sea cliffs (SC) few some roots, rocks | sparse, moist She-oak swamp (SS) sparse | |Gardemtawns (GL) [none _| KEY TO HABITATS DSF: characteristic open woodland (Benson & Falld- ing 1981; Benson & Howell 1990) in exposed posi- tions on Hawkesbury sandstone plateaux, dominated by Angophora costata, Eucalyptus haemastoma, E. gummifera and E. sparsiflora; un- derstorey of sclerophyllous shrubs of Fabaceae, Proteaceae and Myrtaceae; litter layer dense but dry; sandy soil; many ant nests and sandstone outcrops. WSF: in moist gullies and other sheltered locations; many of the same tree species in the canopy, also E. piperita and E. eximia; compared with DSF: shrubs and creepers more mesophyllic and denser, with pockets of smaller trees—Pittosporum undulatum, ristaniopsis laurina and Ceratopetalum apetalum; litter layer dense, moist, compacted; ant nests fewer; soil with more humus but about the same amount of rocky outcrops. GL: cultivated exotic grasses regularly mown to <4 cm high, and probably also treated with fertilisers, herbicides and pesticides; little bare ground and almost no litter. PRY: pine trees (Pinus ragiatee along road verges, rarely mown and graded; deep litter of pine needles; soil with humus-rich, dry layer above hard clay- loam; understorey some Acacia and Pittosporum shrubs, & grasses. wolf, M. rapax none none M. rapax, wolf none none STF: open forest in Fagan Park on ridgetop Wianamatta shale (Benson & Howell 1990), dominated by turpentine, Syncarpia glomulifera; other trees included £. punctata, E. paniculata, E. acmenioides, E. resinifera, E. globoidea and A. floribunda, shrub layer mainly of young trees; ground cover of grasses, logs and sparse litter. SS: estuarine swamp dominated by she-oaks, Casuarina glauca; ero layer of Juncus kraussi, she-oak needles and saltmarsh succulents; lowest areas inundated by highest tides, but areas around sandstone outcrops higher and drier. Bushfire burnt this habitat and dry sclerophyll forest early 1991. SC: sea cliffs immediately above rock platforms in the estuary; vertical walls of loamy soil covered with sparse leaf litter, mosses; some creepers and grasses common around roots of trees and shrubs on cliff edge. The least extensive habitat in area; 10 m or less high along seashore. At Galston, the last habitat was pasture grazed by horse and cattle. Grass height, 6-40 cm; grasses probably fertilised infrequently; patches of bare soil rare. At Patonga, a lawn and bare ground area around a sporting ground was the last habitat, very similar to the pasture at Galston except grass mown regularly to <4 cm high. TABLE 1. Habitat characteristics, with spiders and occurrence of rocks, logs or tree roots. Common spiders = density > 1 per m*. Abbreviations used in text are also given for each habitat. Species were identified by burrow charac- teristics and observations of spiders seen at the burrow entrances either at night or during late afternoons on overcast days. Initially, I ex- cavated at least 30 burrows of each type to obtain specimens for more thorough identification, and to investigate burrow structures and food remains. I measured maximum diameter of all burrows in quadrats (and outside them at some sites to increase sample sizes to >30). I tested for differences among size frequency distributions of burrow diameters using Kolmogorov-Smir- nov (KS) 2-sample tests. Sampling was repeated in late summer (Feb.- March) in some habitats to assess temporal varia- tion between, before, and after the breeding season (roughly mid-sampling). In particular, abandoned burrows (with signs of decay and unoccupied) were notéd. Burrows under rocks and logs were counted in some habitats because funnelwebs seemed restricted to such locations (e.g. short burrows in unconsolidated soils). RESULTS SPIDER SPECIES Six species in three families are here grouped into four ecological types. Misgolas gracilis BURROWING SPIDER ECOLOGY (Rainbow & Pulleine, 1918) is a large idiopid that builds. deep, oblique burrows with a trapdoor among leat litter in friable soils, The lids varied from flimsy and merely silk-covered with a thin layer of dirt to quite robust plugs for older spiders; this may be related also to the amount of litter present. In moist areas, the lid often grew moss and liverworts, M, gracilis was found only in SC und PRY habitats (Table 1). Misgolas rapax Karsch, 1878 is also large with a burrow like M. gracilis but without a trapdoor. Often litter and vegetation around the burrow entrance were incorporated into the flared open- ing. Their burrows were more vertical than those of M, gracilis. The idiopids were identified using Main (1985), Mascord (1970, 1980). M. rapax was found in eight habitats but abundantly only in SS (Table 1). Atrax robusius Cambridge, 1877 is the Sydney furnelweb spider (Hexathelidae). Several similar Species are known from areas near the study locations, but all spiders collected were identified as A. robustus using Gray (1988), Scott (1980), Main (1985), Mascord (1970, 1980) (some smaller spiders were minimally confamilial). Most spiders were found under rocks and logs where characteristic silk tubes led to shallow burrows made in mostly unconsolidated soils and humus. Thus, all spiders were examined im the field but collections were limited to avoid deple- tion of the populations and for safety. Airax was found in only two habitats but was a dominant in both (Table 1). Wolf spiders (Lycosidae) built narrow, vertical burrows without lids and with much flimsier silk linings than did M. rapax. They were identified using McKay (1985) and references therein. The species excavated were Lycosa godeffrayi L. Koch, 1865, £. lewckartii (Thorell, 1870) and Pardosa serrata (L. Koch, 1877), the latter with characteristic palisades around the burrow. Other Species but not excavated include L. furcillata L Koch, 1867, L. pictiventris L. Koch, 1877, and £. palabunda L. Koch, 1877-Due to this uncertainty over the exact identity of the occupants of some burrows, I lumped data on all lycosid burrows into ‘wolf spiders’. I found these in nine habitats but most commonly in WSF (at Patonga only) and PRY (Table 1). ABUNDANCES No spiders or burrows were found in quadrats sampled in the pastures or sports ground (Table 1, Fig. 1), although lycosids had been seen there- Neither habitat will be discussed further. Very S15 MEAN NUMBER PER QUADRAT (+= ne) MEAN NUMBER PER QUADRAT (+/- 5e) FIG. 1. Abundance (no. per 0:25m?*) of each species group versus habitat. A. at Galston, habitats are: J=WSF, 2=DSF, 3=STF, 4=PRV, 5=GL, 6=pasture; B_ at Patonga. habitats are: l=wsr, 2=psr, 3=SC, 4=55, 5=GL, 6=sport ground, MR=M. rapax, MG=M. gracilis, FW= Arrax and WOLF=lycosids. Means and standard errors calculated from n = 20 quadrats in each habitat (i.e. sites were pooled). sparse populations [of only lycosids and M. rapax) were found in open habitats—DSF and GL. The abundance in the five occupied habitats at each location showed differences between habitats and species groups. An ANOVA of total spider density among locations/habitats/ sites (Table 2) showed no significant difference be- tween the locations but large differences among the habitats within locations. At Galston, highest spider densities were found in PRY and WSF habitats, fewer in STF and very few in GL and DSF habitats. At Patonga, SC had the greatest densities, followed by WSF and SS habitats. and very few in the GL and DSF habitats, Habitats with dense spider populations in either Jocation were dominated by a particular species. At Galston, Atrax was the most common spider in the WSF and STF habitats but was not found in other habitats. At Patonga, Atrax was found only in the WSF habitat. M. rapax occurred in four habitats at Patonga and Galston, bul 516 a B ‘ 40+ nt Ls a, ot 8 4 5 6 7 8B Je ma ma | m+ » 2 ar 10 | 0 = Pa a ar a eT 2 & E F eB « « = | | =>) | 30} sot zo k 10 + i 0 + | | 30 i — 80 { € £4 5. 8) ¥ 12 3 48 6 7 B G aot 40} aot so} ar a 10 10 o ° 12 3 4 5 8 7 B 123 45 6 7 8 SIZE CLASS FIG. 2. Representative size frequency distributions of burrow diameter for dense populations of each species. Diameters grouped into eight equal size clas- ses (to show large range with reasonable numbers in each): 1 =0-4.9mm; 2 =5-9.9; 3 =10-14.9; 4=15-19.9; 5 =20-24.9; 6 =25-29.9; 7 = 30-34.9; and 8 = 35mm across the burrow entrance. A) Atrax from WSF, Galston, n = 95; B) Atrax from STF, Galston, n = 59; C) Atrax from WSF, Patonga, n = 50; D) lycosids from PRY, Galston, n = 38; E) M. gracilis from SC, Patonga, n = 189; F) M. gracilis from PRV, Galston, n = 83; G) M. rapax from SS, Patonga, n = 102; H) M. rapax from GL, Galston, n = 79. dominated only in the SS habitat. M. gracilis, in contrast, was found in only one habitat in each location, but dominated the spider assemblage in both. In the SC habitat at Patonga, this species had the greatest mean density found in this sampling (>12 m”). Lycosids were found in five habitats at Galston and four at Patonga but they were never dominant. No species group was either positively or negatively correlated with any other in these samples (for all r, P> 0.05, n = 200). The patchiness of mean spider abundance in any habitat was examined by the Sites within Habitat factor in the nested ANOVA (see Sokal MEMOIRS OF THE QUEENSLAND MUSEUM 20 - iI E st g ae So Bey a Bos 5 O DENSITY 0 @ NUMBER 1 2 3 4 SITE FIG. 3. Abundance of Atrax under rocks and logs in some habitats, expressed as no. per rock or log, and density (no. per m* of rock or log microhabitat). Area of each rock and log estimated from product of two, perpendicular linear dimensions in contact with the ground. Sites (sample sizes) were: 1=WSF at Galston (n = 43 rocks); 2=DSF at Galston (n=27 rocks); 3=STF at Galston (7 =20 logs); and 4=WSF at Paton- ga (n=18 rocks). and Rohlf, 1981). For total spider density and M. rapax alone, the two sites sampled within each habitat differed significantly (Table 2) . Because the sites were chosen randomly from the total habitat, this result indicates medium-scale variability in abundance of total spiders and M. rapax (i.e. at scales of about 100m). Size FREQUENCIES Sample sizes of burrow diameter of sufficient number could be obtained only in habitats with dense populations. The burrow size structure (Fig. 2) of these populations showed differences (by KS tests) among species that were consistent across habitats. Very small burrows (< 5mm) were not found for M. rapax and only commonly for lycosids. Atrax showed bimodality in two habitats with the modes occurring at sizes cor- responding to pre-reproductive juveniles and ma- ture females (Fairweather, unpublished data). The other species had more unimodal burrow diameter frequency distributions. Lycosid bur- rows were much narrower on average than the mygalomorphs (Fig. 2). M. gracilis had the largest burrows overall. TEMPORAL VARIATION Sampling before and after the breeding season showed few changes. The proportion of burrows of M. gracilis in the PRV habitat (Galston) that BURROWING SPIDER ECOLOGY were abandoned and decaying increased from 4.6% (n= 64) in December to 9.6% (nm = 60) in March, These abandoned burrows did not. how- ever, differ in size from the occupied ones (P> 0.05 by KS tests), suggesting no size selectivity in either mortality or abandonment by breeding mules. The proportion of Arrax that were juvenile {i.e, <15mim and with no enlarged pedipalps on males) increased from November to February from 12% (n=67) 10 44% (i = 84) across all three occupied habitats. MICROHABITATS Within each habitat, burrows were found more frequently in particular situations. For example, M. rapax in the SS habitat (Patonga) were only found in areas around rock outcrops and none in the lower, inundated part of the swamp. M. gracilis was most abundant in moist, mossy patches in SC habitat (Patonga) and in areas covered with litter rather than bare ground in the PRY habitat (Galston). All Atrax webs en- countered were seen under or against either rocks or logs, although thorough searches were also made amongst litter and in grass clumps. This prompted sampling centred on rocks or logs in three habitats. at Galston and one at Patonga (Fig. 3). The abundance of Arrax under rocks and logs differed with habitats. None were found in DSF, despite abundant rocks, Counts of webs per rock or log were similar in the three occupied habitats. When expressed on a per area basis (i.e. m° of rock or log). the densities were much greater and differed among these habitats (Fig_ 3). DISCUSSION This study suggests several hypotheses, 1. These species rarely encounter each other in nature, suggesting little ¢ ampeliion occurs among them. | located each species group in more than one habitat, but they tended to dominate different ones. Arrax were favoured by apparently tore moist conditions under shelter; although exfoliated rocks were abundant in the dries DSF habitat, no Arrax were found beneath them. Ad. gracilis was found in relatively exposed positions (sea cliff and road verge) with the most compact soil, whereas M. rapax dominated more open habitats (in terms of the litter and ground layers). Lycosids were the most widespread group, which may reflect that data of several species were lumped. Characterisation of habitats regarding soi], litter and vegetation conditions is needed. 2. Specific habitat characteristics favear dif- 517 aa om i Fe | Location | li2i lose 12 ee eee te lest — ae ee aie Dine has tas dese Dpaae fe TABLE 2, Three-factor, hierarchical ANOVA of den- sity (number per quadrat) of total spiders and cach species group analysed separately. =Significunce at P <0.05 level; df, degrees of freedom; df for residual, 180_ and for total, 199. Total N=200 0.25 m2 quad- rats; only five habitats used here, ferent species. As well as the above habitar segregation, microhabitat preferences were ulsa shown by several groups, most strikingly for Atrax, which was found in moist areas under shelter. Predictive relationships of abundance with environmental variables (e.g. soil nutrients, organic matter, compaction and moisture; litter amount, moisture and temperature; size and depth of shelter) may be established. Experiments on the effects of shelter, litter and moisture condi- tions on the abundance of these spiders are needed. 3, Fosserial spiders respond adversely to many himman impacts on their environments. This has implications for the interaction of these spiders with people and their activities. Few or no fos- sorial spiders were resident in habitats that lacked a litter layer or were regularly mown, watered, treated with chemicals or graded. The spiders can burrow in such open habitats (Fairweather pers. obs.}, 80 perhaps the conditions may not be attrac- tive to prey. There is some longer term evidence of declines in two of these populations associated with increasing urbanisation, direct disturbance, bushfire and vegetative change (Fairweather unpub, date), 4. Dense populations faye been established for several years, at least. Size frequency distribu- tions of burrows revealed juveniles in gach dense population. therefore recruitment had occurred and no population was relict. Several very lar burrows were present in the populations of the three mygalomorphs, probably indicating matnatchs (sensu Main, 1987). The abundance and size structure did not alter from October to March, which implies short-term stability for these long-lived spiders. Behaviour consistent with breeding behaviour over summer was seen for the mygalomorphs. Lycosids with egg sacs were seen only in spring and autumn- 5, Predation by some populations may strongly influence the assemblages of their prey. M gracilis and Atrax were quite dense in particular microhabitats. with some very large spiders; this and their predatory habits suggest that their role as predators in the ground-layer ecosystem would be worth further study. In conclusion, large fossorial spiders are nol evenly distributed across a variety of habitats, and each habjtat is dominated in numerical terms by one or few species. Although the study was done in two contrasting locations, the generality of these results awaits scrutiny with further data as does the cause of any of the patterns described for the first time here. ACKNOWLEDGEMENTS This study was supported by a Macquarie University Research Grant and benefited from the assistance of N. Babicka. G. Napier com- mented upon a draft of the manuscript and two anonymous referees improyed its clarity. LITERATURE CITED BENSON, D, & HOWELL, J. 1990. ‘Taken for granted; the bushland of Sydney and its suburbs’. {Kan- garoo Press: Sydney). BENSON, J.S. & FALLDING, H. 1981. Vegetation survey of Brisbane Water National Park and en- virans. Cunninghamia 1; 79-113, BUCHLI, H.H.R. 1969, Hunting behavior in the Ctenizidae. American Zoologist 9; 175-193. CONLEY, M.R. 1985. Predation versus resource limitation in survival of adult burrowing wolf spiders (Araneae: Lycosidae), Oecologia 67: 71- 75. CURRY, 8.J,, HUMPHREYS, W.F,, KOCH, LE. & MAIN, B.Y. 1985. Changes in arachnid com- munities resulting from forestry practices in kari forest, south-west Western Australia, Australian Forest Research 15; 469-480. FERNANDEZ-MONTRAVETA, C., LAHOZ- BELTRA, R. & ORTEGA, J. 1991. Spatial dis- tribution of Lycosa ferentula fasciiventris (Araneae, Lycosidae) in a population from central Spain. Jonmal of Arachnology 19: 73-79. GRAY, MLR. 1988. Aspects of the systematics of the Australian funnel web spiders (Araneae: Hexathelidae: Atracinae) based upon morphologi- cal and electrophoretic data. Pp, 113-125, In Aus- tin, A.D. and Heather, N.W. (eds) ‘Australian Arachnology’. (Australian Entomological Society Miscellaneous Publication No. 5: Brisbane), HUMPHREYS, W.F. 1976. The population dynamics of an Australian wolf spider, Geelycosa godef- MEMOIRS OF THE QUEENSLAND MUSEUM Jreyi (L. Koch 1865) (Araneae: Lycosidae). Jour- nal of Animal Ecology 45: 59-80. 1988. The ecology of spiders with special reference to Australia, Pp. 1-22. In: Austin, A.D. amd Heather, N.W. (eds). “Australian Arachnology’- (Australian Entomological Society Miscel- laneous Publication No, 5; Brisbane). KOTZMAN, M. 1990. Annual activity patterns of the Australian tarantula Selenocosmia stirlingi (Araneae, Theraphosidae) in an arid area. Journal of Arachnology 18: 123-130. LAING, DJ. 1978. Studies on populations of the tunnel web spider Porrothele antipodiana. Tuatara 23: 67-81. MAIN, B.Y. 1976. ‘Spiders’, (Collins: Sydney), 1985. Arachnida: Mygalomorphae, Pp. 1-48. In Walton, D.W. (ed.) ‘Zoological Catalogue of Australia Yol. 3°. (Australian Government Publishing Service; Canberra). 1987. Persistence of invertebrates in small areas: case studies of trapdoor spiders in Western Australia, Pp, 29-39. In Saunders, D.A., Amold, G.W., Burbridge A.A. and Hopkins, A.J.M. (eds) ‘Nature conservation: the role of remnants of native vegetation’, (Surrey Beatty & Sons: Syd- ney). MASCORD, R. 1970, “Australian spiders in colour’, (Reed: Sydney). 1980. ‘Spiders of Australia: a field guide’, (Reed; Sydney). MCKAY, R.J. 1985. Arachnida: Araneomorphae: Lycosidac. Pp. 73-88. In Walton, D.W, fed) “Zoological Catalogue of Australia Vol. 3’. (Australian Government Publishing Service: Can- berra), MCQUEEN, D.J, 1983. Mortality patterns fora popula- tion of burrowing wolf spiders, Geolyeosa domifex (Hancock), living in southem Ontanv, Canadian Joumal of Zoology 61: 2758-2767. MILLER, P.R. & MILLER, G.L. 1991, Dispersal and survivorship in 4 population of Geolycasa tur- ricola (Araneae, Lycosidac). Journal of Arachnol- ogy 19: 49-54. RAVEN, RJ, 1988, The current status of Australian spider systematics. Pp, 37-47 In Austin, A.D. and Heather, N.W, (eds) ‘Australian Arachnology’. (Australian Entomological Society Misce}laneous Publication No. 5: Brisbane). SCOTT, G, 1980, ‘The funnelweb’. (Darling Downs Institute: Toowoomba), SOKAL, R.R. & ROHLF, FJ. 1981. ‘Biometry’. (Freeman; New York). UNDERWOOD, A.J. 1990. Experiments in ecology and management: their logics, functions and intez- pretations. Australian Jounal of Ecology 15:365- 389, WILKINSON, L. 1990, ‘SYSTAT: the system for statistics’, (SYSTAT: Evanston). BIOGEOGRAPHIC PATTERN OF PHYLOGENY IN A CLADE OF ENDEMIC HAWAIIAN SPIDERS (ARANEAE, TETRAGNATHIDAE) ROSEMARY G. GILLESPIE Gillespie, RG. 1993 11 11: Biogeographic pattern of phylogeny in a clade of endemic Hawaiian spiders (Araneae, Tetragnathidae). Memoirs of the Queensland Muxewm 33(2): 519-526. Brisbane. ISSN 0079-8835, The biota of the Hawailan archipelago offers an ideal system with which to study the dynamics behind the evolutionary process, both because the islands harbour many speciose lineages, and because they are arranged within a chronological time frame. Over the past 5 years I have begun to uncover an unexplored radiation of one of Hawaii's most abundant and conspicuous invertebrate groups: the spider genus Tefragnatha. The current study focuses on a small clade within the lineage, in which all the component species have abandoned web-building, insiead foraging as cursorial predators. I examine 2 primary questions: 1. What has been the relative importance of strict geographic isolation (popula- Hons on different volcanoes) versus divergence between contiguous habitats (populations on the same volcano) in the evalution of this clade? 2, Does the phylogeny indicate a pattern of ecological and distributional change which could suggest that ecological! rather than sexual shifts may underlie species formation? | generated a phylogeny based on morphological characters, and compared this phylogeny to the biogeographic pattern of the Hawaiian Islands. The resulls suggest that, for this clade of cursorial species, speciation requires strict geographic isolation, and ecological (more than sexual) shifts appear to play 4 role in initiwling divergence, Considering the islands as a series of evolutionary snapshots, | would also speculate that speciation is commencing on the youngest island (Hawaii), and develap- ing on the adjacent older island of Maui. [Tetragnatha, phylogeny, Hawaii, speciation, allopatry. Rosemary G, Gillespie, Hawaiian Evolutionary Biology Program, University of Hawail at Manea, Honolulu, Hawaii 96822, U.S.A; 28 October, 1992. Species represent one of the basic units of evolution, yet the processes by which they are formed temain poorly understood (Mayr, 1963). Studies of the Hawaiian biota have lent consider- able insight into the mechanisms underlying speciation. These studies are highlighted by the Hawanian Drosophila, in which sexual selection through female choice appears to play an integral role in inducing species formation among small populations colonizing geographically isolated islands (Carson, 196%; Carson and Kaneshiro, 1976; Kaneshiro, 1988). One may ask whether it is possible to generalize from these studies that adjustments in the sexual environmentare largely responsible for driving species radiations. Other studies outside the Hawaiian Islands have found that ecological changes in isolation are more im- portant in driving species proliferation (Mayr, 1963; Grant, 1986), When a species is released from interaction with related species, by whatever means, it may broaden its habital use and exhibit much more variation among in- dividuals (Lack, 1971: McCune, 1990). The ar- gument is that if Such a reproductively isolated incipient species were reunited with its parent, selection could act on the ecological variability 1a minimize the resources jointly used by both species. leading to further ecological divergence (Mayr, 1963; Grant, 1986). The Hawaiian archipelago (Fig, 1) provides a natural laboratory for studies of speciation (Simon, 1987). First, the extreme isolation of the islands has allowed repeated and explosive diver- sification of species in a large number of lincages including honeycreepers (Berger, 1981; Freed e1 al., 1987), land snails (Cooke et al., 1960), crick- ets (Otte, 1989) and drosophilid flies (Kaneshire and Boake, 1987), Further, the islands area series of volcanoes arranged within an identifiable chronological time frame; the currently high is- lands range from Kauai, the oldest and most eroded, to Hawaii, the youngest, highest and largest, with 5 separate volcanoes. This study uses a lineage of spiders to examine speciation patterns within the context of the Hawaiian archipelago. The spiders belong to the long-jawed orb-weaving genus Tefragnathe, which comprises a large number of endemic species in the Hawaiian Islands (Gillespie, 1991, 1992), Outside the archipelago, Tefragnatha are among the most widespread and conspicuous spiders worldwide, yet collectively they are also 520 KAUA'I Waialeale 5.1 myr O'AHU Waianaes - 3.7 myr Direction of movement of tectonic plate & relationship to island age (myr) N I Koolaus \ 2.6 myr MEMOIRS OF THE QUEENSLAND MUSEUM MOLOKA'! 1.8 myr _Z MAUI West Maui 1.3 myr Haleakala 0.8 myr Kohalas Heer 0.43 myr ye Hualalai 0.40 myr _ Mauna Kea \ 0.38 myr FIG. 1. Major land masses of the Hawaiian archipelago, indicating approximate age, and direction of movement of tectonic plate. one of the most homogeneous, both in morphol- ogy (elongate bodies and long legs) and ecology (orb web generally built over or near water) (Wiehle, 1963; Levi, 1981; Gillespie, 1986, 1987). Hawaiian species of Tetragnatha repre- sent a paradox, exhibiting considerable morph- ological and ecological diversity. Until 1992, the sole reference to endemic Hawaiian repre- sentatives of the genus was based on descriptions of asingle species by Karsch (1880) and 8 species by Simon (1900, redescribed by Okuma, 1988). I have now described an additional 16 species (Gil- lespie, 1991, 1992), and have collected more than 60 new taxa that span a broad spectrum of colours, shapes, sizes, ecological affinities, and behaviours. In terms of courtship behaviour, however, Hawaiian representatives of the genus display the simple cheliceral locking mechanism characteristic of the genus (Levi, 1981; Gillespie, pers. obs.). Here I examine a small clade (the ‘spiny-leg’ clade) within the radiation of Hawaiian Tetrag- natha. Representatives of this clade are charac- terized by a cursorial habit, and do not build webs (Gillespie, 1991). Further, in common with other representatives of the genus (Levi, 1981), but in striking contrast to the Drosophila radiation, these spiders display minimal courtship be- haviour. Because explanations for species forma- tion in the Hawaiian Drosophila rely heavily on the elaborate courtship behaviour of the group, the absence of such behaviour in the Hawaiian Tetragnatha suggests that alternative explana- tions might be required to account for species proliferation. The questions I address in this study are: 1. What has been the relative importance of strict geographic isolation (taxa diverge on dif- ferent volcanoes) versus divergence between contiguous habitats (taxa diverge on the same volcano) in the evolution of the spiny-leg clade of Hawaiian Tetragnatha? 1 generated a phylogeny for the clade based on morphological characters, and then compared the phylogeny to the biogeographic pattern and history of the is- lands. 2. Does the phylogeny indicate a pattern of ecological and distributional change which could suggest that ecological rather than sexual shifts may underlie species formation? METHODS COLLECTION AND ECOLOGICAL MEASUREMENTS Spiders were collected by visual night search- ing at various times of the year between 1987 and 1991 in wet, mesic and dry native forest in all of the currently high Hawaiian Islands (Kauai, PATTERN OF PHYLOGENY OF HAWAIIAN SPIDERS Oahu, Molokai, Lanai, Maui and Hawaii; Fig. 1). Habitats from which spiders were taken were scored as wet (>450cm average annual rainfall), mesic (250-450¢m) or dry (<250 cm). Elevation was categorized as low (<1000 m), medium-low (1000-1700m), medium-high (1700-2000m) and high (>2000m). Microhabitat associations were determined by categorizing the specific site from which an individual was collected (roots, fern fronds, against bark, etc.) (Gillespic, 1987). PHYLOGENETIC ANALYSIS IT used a cladistic approach (Hennig, 1966) based on morphological characters to determine relationships among the spiny-leg clade of Nawaiian Tetragnatha. I scored a total] of characters relating to cheliceral armature (upper and lower tooth rows), leg spination, and colour of the cephalothorax and abdomen (Table 1). In addition, T scored characters from the detailed structure of the male palp using a Hitachi 8-800 scanning electron microscope. I used a Hawaiian web-building species of Tetragnatha, T. stelarobusta Gillespie as an outgroup in the analysis because molecular data indicate that this aa belongs to a closely related sister clade of e spiny-leg species (H.B. Croom, pers. comm.). Characters were analyzed as unordered states {i.e., any character state permitted to transform directly into any other state) using Fitch (Fitch, 1971) and Wagner (Farris, 1970) parsimony in PAUP (Swofford, 1990) under the accelerated transformation method of optimization. Charac- ter states were polarized as primitive or derived by outgroup comparison (Maddison ef al., 1984), and characters were scaled for equal character weighting regardless of the number of states. A hranch-and-bound search was conducted to find the shortest tree, The data were then reanalyzed by Successive approximations, weighting charac- ters according to their rescaled consistency index (Farris, 1969, 1989). RELATIONSHIP BETWEEN SPECIES PHYLOGENY AND IsLAND BIOGEOGRAPHY To test the importance of strict geographic isolation in initiating divergence, and the extent to which regular ecological and distribuuonal changes have accompanied species formation, I compared the resulting phylogeny to the biogeographic locations of the component taxa within the Hawaiian archipelago. RESULTS CoLLEcTION AND EcoLocical, MEASUREMENTS Representatives of the spiny-leg clade of Hawaiian Tetragnatha occur on each of the high islands, All are restricted to wet forest excep! for T. brevignatha Gillespie. T. restricta Simon and T. quasimodo Gillespie. which occur in wet, mesic, and sometimes dry, forest. The ranges over which the different species were found is listed in table 2. Microhabitat associations were loose, although the bright green species (7. tan- talus Gillespie, T. polychromata Gillespie, T: brevignatha, T. macracantha Gillespie, T- waikamot Gillespie and T. kawaiensis) were col- lected almost entirely from leaves, whereas the darker coloured T. kamakou Gillespie, T. per- reirai i Gillespie, T. pilosa Gillespie. T. gquasinada and T. restricia were collected from brown or red-brown substrates. PHYLOGENETIC ANALYSIS When characters were scaled for equal weight- ing regardless of number of states and unordered, a total of 7 mosi parsimonious trees were generated (consistency index 0.517, retention index 0.509). Subsequent weighting by succes- sive approximations had little effect on the tree topology. and gave a single tree of unweighted length 76 (consistency index 0.725, retention index 0,765). Fig. 2 shows the tree with explana- tions of the characters defining each node. The characters defining species are marked as bars. RELATIONSHIP BETWEEN SPECIES PHYLOGENY AND IsL AND BIOGEOGRAPHY As can be seen from this phylogeny based on morphological characters (Fig. 2), the most clase- ly related species are never found on the same island. The only regular pattern of ecological and distributional change through the Hawaiian Is- lands is the broadening habitat usage on the younger islands. In particular, taxa on the oldest islands (Kauai and Oaha) are all endemic to single volcanoes, while on the youngest island, Hawaii, there are no species endemic to the ts- land, despite its much larger size (5 volcanoes). Ja addition, taxa on the youngest island occupy a much broader range of habitat types: 7. brevig- narhe, for example, is found at all elevations and in dry, mesic and wet forest on Hawaii Island, whereas representatives of this species on East Maui occur only in mesic forest at middle eleva- tions. Distributions of representatives of the clade on East Maui show some anomalies. In particular, of ist ot absent /bump/finger la o's!" close to ‘T' (second Jovth down mare nin)? 3 teeth 5 onwards larger than Band 4? iy bonito ee 2 first two teeth well separated? Terminal projection of conductor points: straight! backward/ forward Cap of ae eh OC tip: shallow/ deep Cap ridge of conductor tip: lateral’ [Cap ridge of conductor tip: lateral medial =| lis [s Spur of conductor tip: indistinct/ prominant Floor and spur base of conductor tip: at same Tevel/ separated [25_| Stermmum color; wansluceny opaque Orb webs built’ 2B Seminal receptaciest no swelling/swelling angled down/ tl fh [9 firsticeth: tiny/moderate-size/aslargeasothers tt 2 a [a ES CE CC [eaten oectteen een [No 7 SS mada asdoaass = auayaa3a7338 Backward projection of conductor tip: above/ at same leyel/ aa See below caj Spur of condoctor tip: angled up/ straight out/ hooked down — oo Separation of conductor cap und pleats: large/ small 20 | Cap of conductor: wide/ medium/ high Ae pee et 1 Lanett ess msm amiese® aa fa fafa jo |i jo | 127 _|Tipof & conductor projection: blunv pointed | Pe ke ee angled up | [29 _|Dorsumcolor:brown variable/green toi? fz [2 [2 foo fo fo | Tibia spines (lateral medial, dorsal): 332/ 442/52 lo |: j2 [2 |i f2 fs [2 fo jo fo fa | MEMOIRS OF THE QUEENSLAND MUSEUM Ee Ee fo TABLE 1. Characters used for generating phylogeny. stel = 7. stelarobusta; kau = T. kauatensis; pil = T. pilosa: mac = T. macracantha; pol = perr = T. perretrai, kam = T. kamakou: test = there are three bright green species, one endemic to-this volcano (7. macracantha), one shared with West Maui (7. waikamoi) and T. brevignatha shared with Hawaii Island. The East Maui species exhibit parapatric ranges, with only very narrow zones of overlap, and are more closely related to- species on other islands rather than to each other, DISCUSSION Differentiation between species of the spiny- leg clade of Hawaiian Tefragnatha appears never to have occurred on the same mountain mass: in no situation are two sister species found on the same volcano, or even on the same island. This T. polychromata; tant = T. tantalus; wak = T. waikamot; brev = T. brevignatha, T. restricta; quas =T. quasimodo. phylogeny based on morphological characters therefore strongly suggests that strict geographic isolation (between islands only) is necessary for the imiliation of species formation. Such isolation appears also to underlie speciation events in the Hawajian Drosophila (Carson and Templeton, 1984). The phylogeny of the Hawaiian spiny-leg Tetragnatha also indicates that species colonize in a generally southerly direction, with the most ancestral taxa occupying the oldest island, Kauai. In addition, colonization of the most recent island (Hawaii) may be associated with ecological release: populations of each of the three species that have colonized Hawaii Island, T. guasimodo, T. restricta and T_ brevignatha, occupy a broad PATTERN OF PHYLOGENY OF HAWAIIAN SPIDERS 523 T. pilosa T. kaudiensis 12,13,14,15,16 FIG. 2. Phylogeny of the Hawaiian spiny-leg Tetragnatha based on morphological characters. Explanations are given for characters defining each node; characters defining species are marked as bars. Sketches of the tip of the male conductor (left) and the upper surface of the apical portion of the male chelicera (right) are included for ease of comparison. Arrows point to the location of a species in the archipelago, with the size of an arrow tip being approximately proportional to the size of the distribution of a given species.Character changes defining each node are as follows. 1, Conductor terminal projection: short->long. 2, Conductor cap ridge: lateral— >medial. 3, Conductor cap: rounded—>pointed. 4, Conductor cap tip: blunt—>pointed. 5, Colour: brown/vari- able—green. 6, First upper cheliceral tooth lost. 7, First Jower cheliceral tooth lost. 8, First 2 lower margin cheliceral teeth—> well separated. 9, Conductor backward projection at level—> below cap. 10, Conductor cap: low—>high. 11, Backward projection conductor spur—>angled down. 12, Venter: pale->dark. 13, Abdomen colour: green—>brown. 14, First dorsal cheliceral tooth—>finger. 15, Cheliceral ‘sl’ tooth—> closer to ‘T’. 16, First 2 lower cheliceral teeth—> closer. 17, Conductor backward projection hooked up—> angled down. 18, Lower tooth row long—> short. range of habitat types. In particular, 7. brevig- natha is found in almost every habitat type on Hawaii Island, whereas representatives of the species on East Maui are confined to a narrow band of mesic forest at middle elevation. There are some distinct differences between the pattern of phylogeny I have generated here for the Hawaiian Tetragnatha and patterns suggested for the Hawaiian Drosophila. The Hawatian Drosophila generally demonstrate single volcano endemism, one species having its closest relatives on an adjacent volcano. In contrast, the phylogeny I have generated for the spiny-leg species of Hawaiian Tetragnatha suggests a non- uniform and disjunct pattern. Possible explana- tions for the Tefragnatha pattern may best be 524 MEMOIRS OF THE QU I : Mauna Loa VOLCANO |s_[w lw le |e [sae le fe | | lEievation [1-2 [o-t [1-2 [o-1 |1-2 0-1 [1-2 [04 | se Re esa poivclimm |_| r_ nectocsties [vm] ss] od | af | rT _4 waikamoi rime a |_| fkauiensis [| | | | | | 7 [ | [| kamakou | | | | | perreirai__ | | | pilosa || quasimodo 4 Sl. Po wan Ma [Mola] oan [a | [M.Kea_|Kh | EENSLAND MUSEUM fu [w [Haleakala [Ka |La |Wainaes [Ko |wai| [ [nw [n fe fe [wi] | | | ft [| ria alee ler ea estivles eaten 12 A a Ps es a a ed fie Mieee fT Sale [ee erie pe fet Fe a Ti Eh a a | fx | [x fx [x | | T TT Tt 7 |__| JO Ss | ix | ik | ix] TT | tt ft ft peal = fest ee | |x | fate TABLE 2. Tetragnatha species collected at different sites (islands, volcanoes and elevations, x 100m) through the Hawaiian Islands. Islands: MO= Molokai; LA= Lanai; KA= Kaui. Volcanoes: M. Kea= Mauna Kea;Kh= Kohala; Hu = Hualalai; W= W. Maui; Ka= Kamakou; considered by viewing the Hawaiian archipelago as a series of evolutionary snapshots, with specia- tion starting on Hawaii Island and developing on East Maui. The three species on the recently formed Hawaii Island are likely to be relatively recent colonists that have expanded their range and habitat use. Such ecological release sub- sequent to colonization is considered an impor- tant step in initiating species divergence in Galapagos finches (Grant, 1986). However, the widespread species on Hawaii Island are remarkably homogeneous, and none are endemic to the island. It may be that Hawaii Island is too young for speciation to have occurred in the spiny-leg Hawaiian Tetragnatha. The situation suggests that considerable movement of in- dividuals occurs within the island, and gene flow between islands has been sufficient to prevent speciation during the period of existence of Hawaii Island. The adjacent older volcano of East Maui was once part of the island complex, ‘Maui Nui’ (comprising Molokai, Lanai, East and West Maui). This island was likely first invaded by T. tantalus. Males may be better colonists than females (Bishop, 1990), but spiderlings would also arrive, and eventually give rise to a popula- tion that would expand its range on that island. However, colonists would continue to arrive on Maui Nui, and, at least initially, the original colonists would not be reproductively isolated from the secondary colonists of the same species. It is also possible that, if the secondary colonists included closely related heterospecifics, hybridization might occur, as newly forming taxa tend to have poorly developed sexual discrimina- La= Lanaihale; Ko= Koolaus; Wai = Waialeale. tion (Kaneshiro, 1976, 1983; Carson et al., 1989). Indeed, it is possible that both 7. macracantha and T. brevignatha arose through hybridization, which may play an important element in the formation of species in general (Endler, 1989). As sexual discrimination and ecological adap- tation develop, invaders would presumably lose their ability to colonize an occupied land mass. The pattern of distribution of representatives of the spiny-leg clade on older islands suggests that closely related taxa cannot maintain coexistence on the same land mass unless they have under- gone sufficient ecological divergence. The situa- tion on East Maui may therefore represent an unstable state: ultimately, a single species will take over the land mass, as a result of introgres- sion or competitive displacement. The mechanism I have proposed for speciation among representatives of the spiny-leg Hawaiian Tetragnatha remains speculative. However, the repeated ecological release of newly forming taxa strongly suggests that ecological changes have played some role in initiating species divergence, as does the finding that two populations (Maui versus Hawaii) of an apparently diverging species (7. brevignatha) differ only in terms of their habitat occupation. I suggest that, unlike the Hawaiian Drosophila in which sexual selection has been heavily implicated in the speciation process (Kaneshiro, 1983; Kaneshiro and Gid- dings, 1987), ecological factors (range expan- sion, reinvasion, competition) may be more important among the spiny-leg species of Hawaiian Tetragnatha. PATTERN OF PHYLOGENY OF HAWAIIAN SPIDERS ACKNOWLEDGEMENTS The study was supported by grants from the Hawaii Bishop Research Institute and the Hawaii Natural Area Reserves System with additional support from the Smithsonian Institution, the Bishop Museum, Haleakala and Hawaii Vol- canoes National Parks, Maui Land and Pineapple Company, the Nature Conservancy of Hawaii, Pacific Tropical Botanical Gardens, the U.S. Fish and Wildlife Service, the University of Maryland (Dept. of Entomology), and the University of Hawaii (Dept. of Zoology). I am indebted to the following for their assistance in collecting specimens: R. Bartlett, J. Burgett, H. L. Carson, I, Felger, J. I. Gillespie, J. Halloran, J. Jacobi, K. Y. Kaneshiro, J. Kiyabu, L. Loope, D. Lorence, A. C. Medeiros, S. Montgomery, C. Parrish, S. Perlman, W. Perreira, D, Preston, V. and B. Roth, R. Rydell, W. Stormont, J. Strazanac, M. White and K. Wood. I am grateful to J. A. Coddington, H. B. Croom, H. W. Levi, S. R. Palumbi, N. I. Platnick and to G. K. Roderick for providing advice, discussion and comments. LITERATURE CITED BERGER, A.J. 1981. ‘Hawaiian Birdlife’. (University of Hawaii Press: Honolulu). BISHOP, L. 1990. Meteorological aspects of spider ballooning. Environmental Entomology 19: 1381-1387. CARSON, H.L. 1968. The population flush and its genetic consequences. Pp. 123-137. In Lewontin, R.C. (ed). ‘Population Biology and Evolution’. (Syracuse University Press: Syracuse, New York). CARSON, H.L. & KANESHIRO, K.Y. 1976. Drosophila of Hawaii: Systematics and ecological genetics. Annual Review of Ecology and Sys- tematics, 7: 311-346. CARSON, H.L. & TEMPLETON, A.R, 1984. Genetic revolutions in relation to speciation phenomena: The founding of new populations. Annual Review of Ecology and Systematics 15: 97-131. CARSON, H.L., KANESHIRO, K.Y. & VAL, F.C. 1989, Natural hybridization between the sym- patric Hawaiian species Drosophila silvestris and Drosophila heteroneura. Evolution 43: 190-203. COOKE, C., MONTAGUE, J. & KONDO, Y. 1960. Revision of Tornatellinidae and Achatinellidae (Gastropoda, Pulmonata). B.P. Bishop Museum Bulletin 221: 1-303. ENDLER, J.A. 1989, Conceptual and other problems in speciation. Pp. 625-648. In Otte, D. and Endler, J.A. (eds). ‘Speciation and its Consequences’. (Sinauer Associates: Sunderland, Massachusetts). FARRIS, J.S. 1969. A successive approximations ap- 525 proach to character weighting. Systematic Zool- ogy 18: 374-385. 1970. Methods for computing Wagner trees. Sys- tematic Zoology 19: 21-34, 1989, The retention index and the rescaled consis- tency index. Cladistics 5: 417-419. FITCH, W.M. 1971. Toward defining the course of evolution: minimal change for a specific tree topology. Systematic Zoology 20: 406-416. FREED, L.A., CONANT, S. & FLEISCHER, R.C. 1987. Evolutionary ecology and radiation of Hawaiian passerine birds. Trends in Evolutionary Biology 2: 196-203. GILLESPIE, R.G. 1986. ‘Between population com- parison of resource acquisition in the long jawed orb weaving spider Tetragnatha elongata’. Ph.D Dissertation. (University of Tennessee: Knox- ville: Tennessee). 1987. The mechanism of habitat selection in the long jawed orb weaving spider Tetragnatha elongata (Araneae, Tetragnathidae). Journal of Arachnol- ogy 15: 81-90. 1991. Hawaiian spiders of the genus Tetragnatha: I. Spiny Leg Clade. Journal of Arachnology 19: 174-209. 1992. Hawaiian spiders of the genus Tetragnatha II. Species from natural areas of windward East Maui. Journal of Arachnology 20: 1-17. GRANT, P.R. 1986. ‘Ecology and Evolution of Darwin's Finches’. (Princeton University Press: Princeton, New Jersey). HENNIG, W. 1966. ‘Phylogenetic Systematics’. (University of Illinois Press: Urbana, Illinois). KANESHIRO, K.Y. 1976. Ethological isolation and phylogeny in the planitibia subgroup of Hawaiian Drosophila, Evolution 30: 740-745. KANESHIRO, K.Y. 1983. Sexual selection and direc- tion of evolution in the biosystematics of the Hawaiian Drosophilidae. Annual Review of En- tomology 28: 161-178. 1988. Speciation in the Hawaiian Drosophila, Bios- cience 38: 258-263. KANESHIRO, K.Y. & BOAKE, C.R.B. 1987. Sexual selection and speciation: issues raised by Hawaiian drosophilids. Trends in Ecology and Evolution 2: 207-211. KANESHIRO, K.Y. & GIDDINGS, L.V. 1987. The significance of asymmetrical sexual isolation and the formation of new species. Evolutionary Biol- ogy 21: 29-43. KARSCH, F. 1880. Sitzungs-Berichte der Gesellschaft Naturforschender freunde zu Berlin. Jahrgang. Sitzung vom 18: 76-84. LACK, D. 1971. ‘Ecological Isolation in Birds’. (Har- vard University Press: Cambridge, Mas- sachusetts), LEVI, H.W. 1981. The American orb-weaver genus Dolichognatha and Tetragnatha north of Mexico (Araneae: Araneidae, Tetragnathinae). Bulletin of the Museum of Comparative Zoology Harvard 149: 271-318. 526 MADDISON, W.P., DONAGHUE, M.J. & MAD- DISON, D.R. 1984. Outgroup analysis and par- simony. Systematic Zoology 33: 83-103. MAYR, E. 1963. ‘Animal Species and Evolution’. (Harvard University Press: Cambridge, Mas- sachusetts). MCCUNE, A.R. 1990. Evolutionary novelty and atavism in the Semionotus complex: relaxed selec- tion during colonization of an expanding lake. Evolution 44: 71-85. OKUMA, C. 1988. Redescriptions of the Hawaiian spiders of Tetragnatha described by Simon (Araneae, Tetragnathidae). Journal of the Faculty of Agriculture Kyushu University 33: 77-86. MEMOIRS OF THE QUEENSLAND MUSEUM OTTE, D. 1989. Speciation in Hawaiian crickets. Pp. 482-586. In Otte, D. and Endler, J.A. (eds). ‘Speciation and its Consequences’. (Sinauer As- sociates: Sunderland, Massachusetts). SIMON, C. 1987. Hawaiian evolutionary biology: an introduction. Trends in Ecology and Evolution 2: 175-178. SIMON, E. 1900. Arachnida. Fauna Hawaiiensis 2: 443-519, pls. 15-19. SWOFFORD, D.L. 1990. PAUP 3.0s. Phylogenetic analysis using parsimony, version 3.0. (Illinois Natural History Survey: Champaign, Illinois). WIEHLE, H. 1963. Tetragnathidae. Tierwelt Deutschlands 49: 1-76. \. NEW SPECIES OF KARSCHIIDAE (SOLIFUGAE, ARACHNIDA} FROM KAZAKHSTAN ALEXANDER VY. GROMOV Gromoy, A.V. 1993 11 11: A new species of Karschiidae (Solifugae, Arachnida) from Kazakhstan. Memvirs of the Queensland Museum 33(2): 527-528, Brisbane, ISSN 0079- 8835. The new solpugid species Karschia mangistauensis of the family Karschiidae is described from material callected in south-western Kazakhstan, The relationship of the new species is given, as well as the list of solpugids currently known from Kazakhstan. En se basant surle matériel récolié au Sud-Ouest du Kazakhstan on décrit une nouvelle espéce de solifuge Karschia mangistauensis de ta famille Karschiidae. On donne Ics affinités de la nouvelle espéce aussi gue la liste des solifuges connnes a présent au Kazakhstan.[Solpugids, Karschiidae, Karschia, Kazakhstan, Alexander V. Gromovy, Institute of Zoology Kazakhstan Academy of Sciences, Akadem- goradok, Alma-Ata 32, 480032 Kazakhstan Republic, CIS; 8 March, 1993. The solpugid fauna of Kazakhstan is poorly known. Only 13 species were recorded from the region by Birola (1938): these are Karschia garudnyi Birula, Eusimonia turkestana Kraeplin, Anoplogylippus dsungaricus Roewer, A. rick- mersi (Kraeplin), Henigylippus lamelliger Birula, Galeodes araneoides Pallas, G. turkes- lanus Kraepelin, G. caspius Birula, G. fuscus Birula, G. pallasi Birula,Paragaleodes heliophilus Heymons, P_ pallidus Birula and Daesia rossica Birula. The present paper concentrates on material col- lected from Mangyshlak and Ustyurt Plateaus (south-western Kazakhstan). Solpugids were preserved and studied in 70% alcohol using a binocular microscope MBS-L. Their determina- Won was done according to Walter (1889), Birula (1938) and Roewer (1932-1934, 1941). MORPHOLOGY AND BIOLOGY Family KARSCHIIDAE Karschia mangistauensis sp. nov. (Figs 1-10; table 1) MatTERIAL ExaMINED TYPES. Holotype 6 , Zhylandy Cape. Yeraliev District, Mangyshlak Plateau, Mangistau Area, South-Westerm Kazakhstan, (43°06’ N, 51°39’ B), 2 May 1991, A.V. Gromoy, Paratypes: South- Western Kazakhstan: Mangistau Area: Man- eyshlak Plateau: 2d, 2 9, same data, except 2-4 May 1991, K.U. Balmukanov, A.V. Gromov, K.B. Dzhankurazov; 1 ¢, Aktau City [Shev- chenko], (43°11’N, 51°39°E), 28 April 1991, K.U. Balmukanov; Ustyurt Plateau: I d, Kugusem Well, 68.5 km E of Akkuduk Village. Yeralieyv District, (43°10°N, 54°53"E), 2-5 May 1990, S.I_Ibraev; 1 9, Sulykkyzylsai Well, 69.5 km NE of Akkuduk Village, Mangistau District, (43°28°N, 54°43°E), 12 May 1991, E.E. Kopdyk- baev. Holotype and | 2 paratype preserved in Zoological Institute, St Petersburg [Leningrad], the remaining material in the author’s collection. DIAGNosIs The new species is closely related to Karschia cornifera Walter, 1889 from Turkmenistan, from which it differs by the colouration, by the shape of upper modified mesolateral seta near the base of cheliceral fingers, by the number of teeth on the fixed finger and by the spinulation of pedipalps. DESCRIPTION Male (holotype), Total length 21 mm. Body colouration light yellow-brown, with greyish head and thorax and grey-yellow abdomen with darker tergites. Chelicerae yellow, distally in- cluding brownish-black teeth. Pedipalps (Fig, 4); proximal part of femur yellow, distal part of femur and the remaining segments greyish. Legs yellow. Ocular tubercle (Fig. 1) dark, with numerous hairs, sparse short setae and 2 long setae. Near the base of the cheliceral fingers there is a mesal row of long setae: the upper two are strongly modified and thickened (Figs 2, 3). Ar- mature of pedipalps (Fig. 5): protarsus (basitar- sus, metatarsus auct.) with 9 promesolateral spines, tarsus with 1 mesobasal spine. Third ab- dominal segment with 46 broad ctenidia, fourth one with 19 ctenidia (Fig. 6). Ste La FIGS 1-10. Karschia mangistauensis, sp. nov. 1-6, male; 7-10, female. 1, propeltidium, dorsal view. 2, right chelicera, ectal view. 3, modified setae near base of fingers, and flagellum on left cheliceral fixed finger, mesal view. 4, 5 right pedipalp, mesoventral view; coloration (4); spinulation (5). 6, ctenidia on fourth sternite of abdomen, ventral view. 7, right chelicera, ectal view, 8, right cheliceral fixed finger, ventral view. 9, genital opercula, ventral view. 10, clenidia on fourth sternite of abdomen, ventral view. Scale line = 1 mm. Body length of paratypes 17-2] mm, number of promesolateral spines 6-10, mesobasal spine of tarsus sometimes absent, fourth abdominal seg- ment with 17 or 19 ctenidia. Female paratype. Body colouration lighter than in male, with darker pedipalps. Distal part of femur TV light brown. The head behind ocular tubercle with slight longitudinal light brown line. Ocular tubercle as in male, occupying less than 1/3 of clypeus width. Fixed fingers are straight from above, their length no more than the width of chelicerae. Armature of chelicerae as in Figs 7, 8. Genitalia (Fig. 9) with pale rosy ectolateral setae. Fourth abdominal segment with 19 pale rosy ctenidia which are thicker than in male (Fig. 10). MEMOIRS OF THE QUEENSLAND MUSEUM | (elise —_a 1.6 wide [Propeltidinm |. 4.3.5 wide Pedipalp: total (with coxa) 49 [Leg tit(witheoxa) [16.6 Leg IV (with coxa) 25.4 TABLE 1. Measurements (in mm) of Karschia man- gistauensis, Sp. NOV. BIOLOGY Night solpugid in clayey desert under stones during day. ACKNOWLEDGEMENTS lam grateful to Messrs K.U. Balmukanov and K.B. Dzhankurazoy (Kazakh State University. Alma-Ata) for their assistance in capturing of the new species, Mr 8.1. Ibraev and Mr E.E. Kopdyk- baev (Institute of Zoology, Kazakhstan Academy of Sciences, Alma-Ata) for their material kindly presented to me, and to Dr A.A. Zyuzin (Institute of Zoology, Kazakhstan Academy of Sciences, Alma-Ata) for translation of manuscript. | am also indebted to Dr Ch. K. Tarabaev (Institute of Zoology of Kazakhstan Academy of Sciences, Alma-Ata) who presented my paper at the XII International Congress of Arachnology (Bris- bane, Australia). LITERATURE CITED BIRULA, A.A. [BIALYNITSKIJ-BIRULA], 1938. Solifugae, In: Fauna of the USSR, Arachnida, vol, 1(3). (Academy of Sciences of the USSR: Mos- cow-Leningrad. (in Russian) ROEWER, C.F. 1932-1934, Solifugae, Palpigradi. In: Dr H. G, Bronn’s Klassen und Ordnungen des Tierreichs, Teil 5, Abteilung 4, Buch 4, 723 pp. Bremen, 1941, Solifugen 1934-1940, Veréffentlichungen aus dem Deutschen Kolonial- und Uberseée- Museum in Bremen 3(2): 97-192. WALTER, A. 1889. Transkaspische Galeodiden. In: Wissenschaftliche Ergebnisse der im Jahre 1886 in Transkaspien | (Zoologische Abtheilung), Lieferung 6: 103-117. A NEW SPECIES OF AMAUROBIOIDES O.P.-CAMBRIDGE (ANYPHAENIDAE: ARANEAE) FROM SOUTH AUSTRALIA D.B. HIRST Hirst, D.B. 1993 11 11: A new species of Amaurobioides O.P.-Cambridge (Anyphaenidae: Araneae) from South Australia. Memoirs of the Queensland Museum 33(2): 529-532. Brisbane. ISSN 0079-8835. The littoral spider Amaurobioides isolatus sp. nov. is described from South Australia and is the first new species of the genus from the Australian mainland. The male palp of A. litoralis Hickman is re-illustrated. Biogeography is discussed. [Araneae, Anyphaenidae, Amaurobioides, new species. David B. Hirst, South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia; 6 November, 1992. The genus Amaurobioides O. Pickard- Cambridge, 1883 occurs in New Zealand (Cambridge, 1883), Campbell Island (Hogg, 1909), South Africa (Hewitt, 1917) and was reported from Tasmania (Hickman, 1949) and Chile (Forster, 1970). Forster (1975) included the south-east coast of Australia in the distribution of the genus but that was not cited by Main (1981) or Davies (1986). The specimen(s) to which Forster (1975) referred were deposited in the Australian Museum, Sydney (AM) but were not labelled as Amaurobioides (unpublished data) and have not been found (pers. comm., M. Gray). No further material has been reported from main- land Australia. Once Amaurobioides was found on the rocky shoreline of the eastern side of Gulf St Vincent in South Australia , deliberate search- ing in similar habitats on Eyre Peninsula, Fleurieu Peninsula and Kangaroo Island showed the species was widespread. Types of A. litoralis Hickman, 1949 (syntype T ‘ cat | amsasensntenr en H — Va +32° oe } TA n | f At } on fe | ¥. / 2? | ~ a fd i] all ' aes, we I) tr ' Cy? < | 4 36 \ j Y 1 a J ! 200 Km ‘ ' | \ ! o o —. ! unk fe is n ig | FIG. 1. Southern portion of South Australia showing the distribution of Amaurobioides isolatus. Shaded coastline may include suitable habitats. series of 1 d and3 ¢ @ from Tasmania) deposited in AM, were examined. Hickman made no special type designations but the male seen (AM KS6410) is labelled ‘Holotype’. Hence, the label designation is invalid (Art. 73iii). The series also includes two females of an undescribed species (Forster, 1970). Forster, when noting that this type material com- prised two sympatric species, stated that the larger form was A. litoralis while the smaller form was undescribed. Sternum length:width ratios Species FIG. 2. Comparison of sternum length: width ratios: a, b, A. litoralis: small form (a); large form (b); c, A. isolatus. m, mean. Siu o.25mm FiG, 3. A- litoralis. Tibial apophysis and cymbium of syntype ¢ AM KS6410, ventral. The 2 is similar in size to the sole smaller 2of the type series, and not to the two larger ? Yas suggested by Forster (also captions for figures of the two forms appear to be transposed as the larger specimen figured is called the small form). This is supported by comparisons of the sternum length:width ratio (Fig. 2). Ratios: 4, 1.65 and smaller type ¢ 1.67; larger 2 2, 1.77, 1.81; @ A, isolatus 1.48-1.60 (n=14, mean =1.56) and 2 32, 1,5), 1.60, Although based only on Australian material seen, the conspecific d of the larger and undescribed form would probably at- tain a ratio in excess of 1.70. The ¢ palp of A. litoralis is r-illustrated here; the Pepigynum was adequately illustrated in Forster (1970, figs 487, 488). METHODS AND MATERIALS Hairs are omitted from illustrations. 2 genitalia were cissected then cleared in lactic acid. Al measurements are in millimetres, Abhreviutions : CL, carapace length; CW, carapace width; AL; abdomen length; AW, abdomen width, MOQ. median ocular quadrangle; aw, anteror width; pw, posterior width; Lorl length, W, width; K_L., Kangaroo Island; DH, D. Hirst. MEMOIRS OF THE QUEENSLAND MUSEUM Amaurobioides isolatus sp, nov. (Figs 1, 2, 4-9, Table 1) MATERIAL EXAMINED TYPES. Holotype d, Blanche Point, 35°{5'S, 138°28'E, 1.iii.1986, DH, N1992206. Paratypes: al- lotype 2, same data as aboye, N1992207; Y (with spiderlings), Elliston, 33°39'S, 134°53"E, 31.iii.1987, DH, D. Lee, N1992218; &, juv., same data, N1992216-7; 9, 5 penult. d, 2 penult. 9, same data as holotype but 25.1.1986, N1992208-15; penuli. ?, Petrel Cove, 35°36’S, 138°36E, 1.ii.1991, DH, N1992219, 9, 4 juv., Point Avoid, 34°41°S, 135°19"E, 31.11.1987, DH, D. Lee, N1992221: 2 (with spiderl- ings), juv.. same data, N1992220; 2 2, juv., Point Ellen, K.¥., 36°00’S, 137°11°E, 10.x1,1987, DH, N1992222-3; @(with eggsac), Point Tinline, K.1., 35°59'S, 137°37'E, 11.x1.1987, DH, N1992224; d 2, Port Willunga, 35°16°S, 138°28°E, in retreats 0.5m above hase of large rock on beach, 14,vi.1992, DH, N1992234-5; 4 9, juv., West Bay, KI, 35°54’S, 136°32°E, 6,x1.1987, D, N1992225-9, All in South Australia and deposited in South Australian Museum. Dracnasis The 3 of A. isolatus is recognised by the shape of the primary conductor. A. isolatus further dif- fers from the two Tasmanian species in having the sternum relatively broader while the 2 epigynum is smailer and less sclerotised. The ¢ has spination of tibia Lidentical to the @ , a feature shared with A. maritimus O.P.-Cambridge, from which it is separated by the genitalia. DESCRIPTION MALE. CL 3.79, CW 2.56. AL 4.48, AW 2.41. Colour in alcohol: Carapace yellow-brown, yellow posterior to fovea and laterally to above anterior Jegs, caput dark orange-brown, clypeus and lateral edge of face brown. Chelicerae red- brown, darker distally, Maxillae and labium orange-brown, anterior margins cream. Sternum cream, margins orange. Legs cream-yellow, antenor metatarsi and tarsi darker, coxae cream. Palp cream, cymbium brown. Abdomen cream with dark red-brown pattern dorsally and lateral- ly. typical for genus. Venter darker around spiracle and posteriorly to spinnerets, dark area extending anteriorly from spiracle in two narrow lines almost to epigastnc furrow. Carapace elongate, longer than broad in ratio 19:13, short imperfect longitudinal fovea [presumably straight in normal specimens]. Suiae barely evident, adpressed setae black, upright setae on caput between fovea and ocular region. Eye group occupies less than half width of caput. AME 0.10, ALE 0,17. PME=PLE0.18. SOUTH AUSTRALIAN AMAUROBIOIDES | |uegi [ueg2 [uegs |tega [Pap | [pa_|1.530.59) |1.56(1.48) [1.3301.39) |1.47(1.50) [0.5900.65) | [Me_|3.19@.34) |2.99@.25) |2.40(1.96) |2.59@.15) |-(-) | TABLE 1. Leg lengths of Amaurobioides isolatus. Values are for holotype ¢ (allotype 2). Interspaces: AME-AME 0.05, AME-ALE 0.04, PME-PME 0.11, PME-PLE 0.12, AME-PME 0.14, ALE-PLE 0.08. MOQ; aw: pw: | = 0.26: 0.47: 0.39. Width of clypeus to AME 0.10. Chelicerae with three teeth on both margins. Ster- num: L 2.12, W 1.40. Legs. (Table 1) Scopula sparse, particularly on posterior pairs. Leg spina- tion; no spines on patellae or tarsi. Ventral tibiae and metatarsi spines usually paired, occasionally single. Leg I, fe d3 p1, ti v6, me v3. Leg II, fe d3 pl, ti pl v6, me v4. Leg III, fe d3 pl rl, ti pl rl v5 (v6 on right), me p3 r3 v6. Leg IV, fe d3 pI rl, tirl v3, me p2 r2 vS. Palp, fe d3 pl, pa with one stout bristle dorsally at distal end, ti many long stout bristles, cymbium with three short weak spines prolaterally. Palp. Tibia with left apophysis having short FIGS 4-7. A. isolatus. 4-5, Left tibial apophysis and cymbium of holotype ¢, 4, ventral, 5, retrolateral; 6, right tibia and apophysis; 7, epigynum of allotype ?. 531 ( x : J i se MS ray % : } E ( ‘ ( fe : LN \ ‘ oe I ae al \ 4} io A} } J ro SE - “4 Te 4) CY FIGS 8-9, A. isolatus, 8-9, cleared vulva of paratype @ N1992208, 8, ventral, 9, dorsal. dorsal median secondary prong (Fig. 5), right apophysis lacking accessory prong (Fig. 6), pos- sibly normal state. FEMALE (as 3 except as follows).CL 4.21, CW 2.89. AL 6.97, AW 4.16. Eyes. AME 0.11, ALE 0.20, PME 0.19, PLE 0.20. Interspaces; AME -AME 0.08, AME-ALE 0.06, PME-PME 0.12, PME-PLE 0.14, AME- PME 0.17, ALE-PLE 0.10. MOQ; aw: pw: 1 = 0.29: 0.50: 0.46. Width of clypeus to AME 0.06. Sternum: L 2.30, W 1.48. Legs. (Table 1) Epigynum. Fossa broad, anterior margins vaguely defined by what appears to be sub- cuticular sclerotisation of vulva (Fig. 7). Vulva of paratype N1992208 shown in Figs 8, 9 [allotype not dissected]. VARIATION CL of paratype ¢, 3.48; the tibial apophysis of both palps lack accessory prongs and the fovea is straight. CL of paratype 2 ; 3.22-4.74, mean 4.35 (n=13). ETYMOLOGY The specific epithet, isolatus, reflects the iso- lated nature of the species distribution. NATURAL HISTORY Habits are similar in other Amaurobioides. Silk retreats are assumed to be permanent although many spiders collected or observed at Blanche Point in February were wandering over the rocks at night. Several penultimate ¢ 5 2 2 were col- lected in this way and kept alive for some time, one ¢ eventually maturing 3 months later. Most insects placed with the spiders, including moths and terrestrial isopods, were not fed upon. Small flies (mostly Drosophila) were more readily ac- cepted (Forster, 1970: 167). Littoral isopods were not tried as a food source (Hickman, 1949). Since then a specimen of A. isolatus at Blanche Point lunged at and grasped a small littoral isopod half its size with its anterior legs, hesitated and then released the isopod, retreating to its position at the entrance to the nest. Small flies, often seen resting 532 im sheltered areas at night along the coast, are another likely food source. Females with spiderl- ings (26 and 42) in the retreat were found in mid-autumn at both Point Avoid and Elliston while spiderlings and an eggsac were found in Separate retreats in November on Kangaroo Is- land. BIOGEOGRAPHY Most areas sampled were within the splash zone onrock faces sheltered from the full yelocity of the sea, but retreats were seen in an exposed and treacherous area at Cape du Couedic, Kan- garoo Island. Known populations are separated by unsuitable or sandy coastline of varying lengths (Fig. 1). Amaurabioides may have dis- persed across the intervening ocean by parachut- ing on silk lines or drifting on flotsam to setile and inhabit their present littoral environments. Forster (1970) considered that claim to be over- stated as a number of distinct forms, some sym- patric, were present in New Zealand. Platnick (1976) reinforced that in the Laroniinae. Since Australia’s separation and subsequent dnft from the other continents of Gondwanaland, the South Australian coastline has been altered by changes in sea level during the last ice-age. The rocky cliffs of Blanche Point and southern coast of Kangaroo Island which now provide a habitat for Amaurobivides were formed during the last ice-age over Tertiary deposits and have since been uplifted and weathered (Daily et al., 1979), One population in D'Estrees Bay, Kangaroo Is- land. consisted of only a few individuals on a small isolated rock outcrop backed by a low sandstone ledge. Similarly, near Port Willunga and 2km south of Blanche Point, individuals exist on a few older limestone rocks remaining on the wide sandy beach which are reached by the nor- mal high tide. Although backed by cliffs, no spiders were found on these, Cliffs also abut the sea in areas north of Blanche Point to Marino Rocks but as yet Amaurcbioides has not been found. Amaurobinides is unlikely to be found from Victor Harbour on the Fleurieu Peninsula to it least Robe in the south-cast of South Australia. Extensive sand dunes which now form the Coorong and much of the coast to the south are part of that area built up during inundation by the sea in the Miocene and the Pleistocene, and the few rocky oulcrops now present have remained isolated since. In summary, Antauribioides is one of the few true Gondwanan spider genera Jeft in South MEMOIRS OF THE QUEENSLAND MUSEUM Australia presumably because continual changes to the coast have occurred gradually, Littoral spiders have moved with it through dispersal and colonising adjacent new areas of rocky terrain or re-establishing itself into old areas within a suitable distance from the receding or insurgent sea. The sympatry of species of Amaurabioides in New Zealand and Tasmania probably occurred by migration ever land following uplift or weathering of unsuitable coastline between twa separated specics and exposing a continuous rocky habitat, rather than by dispersal on silk lines. ACKNOWLEDGEMENTS fam grateful to Dr M. Gray (AM) for the loan of types of the Tasmanian Amanrobioides and to Mr L.N, Nicolson for commenting on an early draft of the manuscript. LITERATURE CITED CAMBRIDGE, 0.P.- 1583, On some new genera and species of spiders, Proceedings of the Zoological Society of London 1883: 352-365. DAILY, B.. MILNES, A.R, TWIDALE, C.R., BOURNE, J.A. 1979. Geology and geomorphol- ogy. In ‘Natural History of Kangaroo Island’. {Royal Society of South Australia: Adelaide), DAVIES, V.T: 1986. ‘Australian spiders, Araneae, Col- lection, preservation and identification’. {Queensland Museum Booklet No, 14. Brisbane). FORSTER, R.R. 1970, The spiders of New Zealand. Part If. Otago Museum Bulletin No, 3: 1-184, 1975, The spiders and harvestmen, Jn Kuschel, G, (ed.) ‘Monographiae para art biogeography and ecology of New Zealand’. (W. Junk: Nether- lands). HEWITT, J. 1917. Descriptions of new South African Arachnida. Annals af the Natal Museum 3; 687- 7 HICKMAN, V.Y. 1949. Tasmanian littoral spiders with notes on their respiratory systems, habits and laxonomy. Papers and procecdings of the Royal Society of Tasmania 1948: 31-43. HOGG, H.R. 1909. Spiders and Opiliones from the Subantarctic Islands of New Zealand. The Suban- lurctic Islands of New Zealand |, Wellington 1909, 155-181. MAIN, BY. 1981. Australian spiders: diversity, uis- inbution and ecology. In Keast, A. (ed.) ‘Eeologi- cal Biogeography of Australia’ Vol, 2. (W. Junk, Netherlands). PLATNICK, N.f. 1976. Drifting spiders or continents?: vicanance biogeography of the spider subfaniily Laroniinac, Systematic Zoology 25: 101-109, IMPLICATIONS OF THE PHYLOGENY OF PIMOIDAL FOR THE SYSTEMATICS OF LINYPHIID SPIDERS (ARANEAE, ARANEOIDEA, LINYPHIIDAE) GUSTAVO HORMIGA Hormiga, G. 1993 11 11: Implications of the phylogeny of Pimoidae for the systematics of linyphiid spiders (Araneae, Araneoidea, Linyphiidac). Memoirs of the Queensland Museum 33(2): 533-542. Brisbane. ISSN 0079-8835. The araneoid family Pimoidae (new rank) is hypothesized to be the sister group of Linyphiidue. Louisfagea Brignoli is a junior synonym of Piroa Chamberlin and Fvie (new synonymy). The characters that support the monophyly of Pimoidae and of Linyphiidac plus Pimoidae are discussed. Explicit outgroup comparison to the closest relatives of linyphiids (ic. pimoids) allows studies of character evolution and character polarization within linyphiids and the assessment of previous phylogenetic hypotheses for the family. Prelimi- nary data on ihe implications of pimoid phylogeny for linyphiid systematics are evaluated, based mainly on morphological characters, Linyphiid monophyly is discussed. La familia arancoide Pimoidae (nuevo rango) es, hipotéticamente, e] grupo hermano de- Linyphiidae, El género Lowisfagea Brignoli se considera sinGnimo de Pimoa Chamberlin and lvic (nueva sinonimia), Se discuten los caracteres que apoyan la monofilia de Pimoidae y de Linyphiidae mas Pimoidae, La utilizaci6n explicita del criterio de comparacién con el grupo externo de los linifidos (es decir, los pimdidos) permite estudiar la evolucién y polarizacién de caracteres en linifidos, asi como ja evaluacién de anteriores hipdtesis filogenéticas sobre esta familia, Se evaluan los datos preliminares, basados en caracteres morfologicos principalmente, sobre las implicaciones de la filogenia de los piméidos para la sistematica de los linifidos. También se discute Ja monofilia de Linyphiidae. Pimoidae, Linyphiidae, Pimoa, cladistics, phylogeny, menophyly, homology, Gusiavo Hormiga, Departmen of Entomology, NHB 105, National Musexm of Natural History, Smithsonian Institution, Washington, DC 20560, U.S.A. and Maryland Center for Systematic Entomology, Department of Entomology, University of Maryland, College Park, MD 20742, U.S.A.; 27 October, 1992. Linyphiids are one of the dominant spider f#roups in the Holarctic region. Despite their over- whelming diversity and involved taxonomic his- tory the phylogenetic structure of the family and their relationship to other araneoids are very puorly understood. In this paper [ present some preliminary data on the systematics of pimoids, confirming their sister-group relationship to linyphids, and on the cladistic structure of a small sample of linyphiid genera, A revision and numerical cladistic analysis of the pimoids and the sample of linyphiid taxa (Hormiga, in press), together with detailed character information, will be published elsewhere shortly. The study of the phylogeny of the pimoids requires the inclusion of at least a sample of linyphiids (their putative sister-group) in order to assess character state polarities by means of outgroup comparison. It is in such a context that the present study should be considered, since the small] sample of genera used here can by no means account for the whole range of linyphiid diversity. However, quantitative cladistic analysis of the data presented here enables for some testable hypotheses on linyphiid systematics and character evolution, by explicitly stating phylogenetic relationships in terms of synapomorphies rather than by the more specula- tive approaches that have commonly been used in traditional linyphiid higher systematics. This approach enables us to evaluate comparalive morphological data (or any other kind of bialugi- cal data) in a cladistic context. Hypotheses on phylogeny and character homology hypotheses are indistinguishable because ‘every hypothesis of homology is a hypothesis of monophyletic grouping’ (Patterson, 1982). Finally, the present study allows for a preliminary test of the phylogeny of the linyphiid subfamilies proposed by Wunderlich (1986). MATERIALS AND METHODS TAXA Nine linyphiid, five pimoid, and two non linyphid araneoid genera that are possible out- groups of the pimoid-linyphiid complex are used in this study. The linyphiid taxa selected repre- sent the subfamilies and tribes used by Wunder- 534 lich (1986) im his phylogenetic scheme for Linyphiidae (given here in parentheses): Linyphia tnangularis (Clerck) and Micro- linyphia dana (Chamberlin and Ivie)(Liny- phiinae, Linyphiini); Bolyphantes luteolus (Blackwall) and Lepthyphantes tenuis (Black- wall)({Linyphiinae, Micronetini); Brigone psychrophila Thorell and Walckenaeria directa (O.P_-Cambridge) (Erigoninae); Haplinis diloris (Urquhart) and Novajroneta vulgaris Blest (Mynogleninae); and Stemonypheantes blauveltae Gertsch (Stemonyphantinae), The pimoids (which contain 21 species, including 1] new species (Hormiga, in press) are represented here by five species: Pimou (=Louisfagea) rupicola (Simon), P. (=Louisfagea) crispa {Fage), P- al- lioculata (Keyserling), P. breviata Chamberlin and Iyie, and P. curvata Chamberlin and Tyic. Tetragnatha versicolor Walckenaer and Zygiella x-notata (Clerck) are used as outgroups of the pimoid-linyphiid clade. The affinities of Zygiella are problematic: the genus is currently placed in Tetragnathidae, although not long ago it was thought to belong in Araneidae. Recent analyses of Araneoidea relationships by Coddington and Scharff suggest that Zygiella is either sister to Araneidae or Araneiae, i.e. it is the most basal taxon within arancids or basal within the araneine clade (Scharff and Coddington, pers. comm.). Taxonomic note: | have used taxonomic decisions that will be soon discussed in greater detail elsewhere. The Pimoinae Wunderlich are raised to familial status (Pimoidae, NEW RANK) and are therefore removed from the Linyphiidac. Treating pimoids as a linyphiid subfamily produces a great change in the diagnosis of Linyphiidae, sinve it Is largely based in male genifalic characters which are absent in the Pimoidae (e.g,, Intersegmental parucymbium, loss of the arancoid conductor, loss of the araneoid median apophysis, presence of a radix and a column, etc.). Once it is established that pimoids and linyphiids are sister-groups, the as- sigument of ranks is arbitrary. The exclusion of pimoids renders Linyphiidae more homogeneous and easier to diagnose. Lowisfagea Brignoli, as presently defined, is polyphyletic (Hormiga, in MEMOIRS OF THE QUEENSLAND MUSEUM press). The removal of crispa would leave the remaining species of Lowisfagea as a paraphyletic genus. Louisfagea is regarded here as a junior synonym of Pimog Chamberlin and Ivie (NEW SYNONYMY). Throughout this paper the taxon name Linyphiidae (linyphtids) does not include the pimoids. CHARACTERS The data set contains 47 characters (Table 1): 33 male and female genitalic characters, 5 spin- Netel spigot characters, 7 other morphological somatic characters, and 2 behavioral characters. The data consist mostly of original observations, butafew characters have been extracted from the literature. Although this data set integrates jnfor- mation from several character systems, it espe- cially focuses on male palp and spinneret spigot morphology. The methods of study and of homol- ogy assessment of spinneret spigot morphology follow those of Coddington (1989), The work on linyphiid morphology (including the descriptive Studies on male palp, spinneret spigot, and tracheal system morphology) will also be pub- lished elsewhere. ANALYSIS The data set was analyzed using the computer program for phylogenetic analysis Hennig&o ver. LS (Farris, 1988). Multistate characters were treated as non-additive (unordered). RESULTS CHARACTERS Character distributions are summarized in Table t- The desmitracheate jracheal system (sensu Millidge, 1984: character 35) is a synapomorphy of the erigonine clade. I have not been able to confirm some of the tracheal mor- phologics described by Millidze (1986). I have examined the tracheal system of several crigonine genera (Arigone aletris Croshy and Bishop, E. psychrophila, Gonatium rubens (Blackwall), Grammonote angusta Dondale, and Hypselistes florens (O.P.-Cambridge)) and have not found evidence of the median tracheae open- TABLE I. Rows represent characters and columns taxa, The first state is ‘state 0°, the second is ‘state 1*, ete. ‘7° represents missing data, and “—" non-applicable states. The last two columns give the consistency index (C1) and the weight (W) assigned to the character in the successive character weighting analysis (see text). Taxon numbers: 0= Tetragnatha versicalor, | = Zygiella x-netara, 2 = Linyphia triangularis, 3 = Microlinyphia dana, 4 = Bolyphantes luteglus, 5 = Lepthyphantes tenuis, 6 = Erigone psychrophila, 7 = Walckenaeria directa, & = Haplinis diloris, 9 = Novafroneta vulgaris, 10 = Stemonyphantes blauyeltae, The remaining taxa are species of Pimoa: || =rupicola, 12 =crispa, 13 =altioculata, \4=breviata, 15 =curvata.Characters: 1-30, male genitalia; 31-33, female genitalia; 34-40, somatic morphology; 41-45, spinnerel spigot morphology; 46, 47, behaviour. PIMOIDAE AND SYSTEMATICS OF LINYPHIIDAE 535 O |1 |2 |3 {4 {5 [6 |7 [8 {9 [10]11]12}13]14]|15|Cr WwW 1 pesoengs roi aa dorsoectal denticulated 0 Jo lo lo lo Jo Jo Jo lo Jo fo fa Ja a Ja Ja fa00 }10 2_|DDP denticles: numerous (20); few (<20) —/—|—|/—|— |-— |—|— |— |— |— ]0 [0 }1 ]1 |1 «4100 {10 3_|Pimoid cymbial sclerite (PCS): absent; present 0 |O {0 |O |O |O |O |O JO JO JO }1 f1 fi 1 f1 $1.00 | 10 | 4 i Hen mnie! dina sclerotized, rigid; —|-|-IEIF IE |H}=-|- KEE ofa Ja da |1 |100 }10 |5__|PCS membranous ridge: absent; present lH |— |= |— | | | | | | | 0 [0 [0 0 [1.00 [10 6 _| PCS shape: U; elongated anteroposteriorly; reversed J —/—|—|— |— |— |— | || |— 9 {2 }1 }1 }1 41.00 {10 7_|Paracymbium attachment:integral; intersegmental 1 {0 |1 {1 {1 {1 [1/1 |1 J1 [1 [O [0 |O JO JO {050 |4 Paracymbium morphology: straight; large-pointed apex; 8 |UorJ; linguiform-fused to PCS; triangular; short- 0 3/3 /3 |3 |3 |3 ]3 |3 |2 |4 |6 {5 {5 |5 |1.00 |10 pprocttved: St_type 9 | Paracymbium apophyses: present; absent 0 1 {i }O [O {1 fl {1 [1 JT [1 ft fi fi ji [0.50 [3 | 10 | Petiole:otherwise; fused to subtegulum 0 hi 1 {1 |] [1 Jl ji fl 1 {i ji jl fl }1.00 [10 11 | Tegular suture: conspicuous; subtle or absent —|—|—|/— |— }|— |— |— ]— |— |— ] 0 {0 | 1 {1 {i }1.00 [10 12 | Mynoglenine tegular apophysis: absent; present 0 {0 |0 {0 |O |O0 {0 |O0 {1 {1 |O JO {O JO {O JO |1.00 |10 13 | Suprategulum: absent; fused; articulated Oo |O |1 {1 {1 |1 [1 ]1 [0 {O [2 [0 |O |O JO JO {1.00 | 10 14 | Median apophysis: present; absent 1 {O [1 ft ft fd ft ft {a fa {1 [GO JO {Oo {1 |i [033 43 15 | Conductor: present; absent 0 |O j1 j1 {1 {I {1 |1 [1 {1 [1 [0 JO }0 JO JO {1.00 | 10 16 | Conductor form: small and undivided; large and bilobate_|O0 [0 |—|—|—|—|—|—|— —j|0 |O |O {1 {1 |1.00 |10 17 | Embolus length: long and filiform; short 0 {0 |0 {0 }1 |1 {1 |0 {0 {O |O {O JO |O JO |O {0.50 }2 18 | Embolic membrane: absent; present —|O {1 {0 {1 |i fl fl jl fil [O |—j|—|—|—|—]0.50 |2 | 19 | Pimoid embolic process (PEP): absent; present __|0 {0 /0 {0 |0 |0 {0 {0 |O }O JO {1 JI Jt {td [1 |1.00 |10 20 | PEP conformation: undivided; divided —|—|—|—|— |-— |-—|—|— |—|—]}1 }90 [0 {0 [0 |1.00 |10 21 | PEP base: narrow; wide and lamelliform — —|—|—|—|-—|-— |—|— |— |0 {0 }1 {1 J1 41.00 |10 22 | Radix: absent; present O jl {1 {1 [1 fi fi ji fi fl fi |O JO |O [0 JO |0.50 {4 23 | Column (distal haematodocha): absent; present O {1 jl {1 {1 Jl [1 Ji [1 {1 J1 JO JO |O {O |O }0.50 {4 24 | Fickert’s gland: absent; present 0 {O |O |O }1 }1 {0 |O JO JO |O |O {0 |O0 {O {O |1.00 {10 25 | Terminal apophysis: absent; present —|O {1 {1 {1 [1 [1 [0 {O JO |O |—|—|—|—|—]0.50 |3 26 | Lamella characteristica: absent; present —/0 {1 /1 {1 J|1 JO JO [0 JO {O |—j—|—|—|—]1.00 |10 7 Speiipalpalsibtel epcgiyeik absent; dorsal, rounded; 0 lo lo lo lo Jo J2 |2 Jo fo J3 Ja Ia Ia Ia Ja |4.00 I10 28 | 3 pedipalp tibial spines: not clustered; distal row O {0 {0 [0 JO 10 |O {0 [O JO JO JO JO JO j1 {1 J1.00_| 10 29 | Prolateral trichobothria in male palpal tibia: two; one 0 {|O jl {1 {1 Jl {1 j1 [O {1 Ji [O |O |O {O [O |0.50 |4 30 | Retrolateral trichobothria in 3 palpal tibia: 2; 4; 3;>4 1 |O |2 {0 |O {0 {0 JO {2 |O {O {2 {2 {2 |2 |2 |0.50 |3 31 | Epigynum form protrudes: less than its width; more —|0 |O |O [0 |O {0 |O |O |O |O {oO |1 [1 [ad [1d [1.00 [10 | 32 | Dorsal plate of epigynum, projections: absent; present 0 j|O0 |0O |O {0 |O {0 |O |O JO {O |O JO |O }1 {1 }1.00 {10 33 | Atrium: absent; present —|0O {1 {1 {0 |O |0 JO |1 {0 |O JO JO |O0 {0 {O {0.50 {2 4 | Mynoglenine cephalic sulci: absent; present 0 {0 {0 |O |O /O [? {O {1 {1 JO |O {O {0 |O [0 |1.00 |10| 35 | Tracheal system: haplotracheate; desmitracheate 0 |0 |0 /O {0 |O {1 {1 [0 JO {O |O JO {0 JO {O | 1.00 {10 Ectal chelicerae of 5: smooth; with stridulatory striae 0 {0 |O [1 [i [1 JO [t ft ft [i fd ft ft ft ft }033 | Retrolateral teeth 9 chelicera: 3; >3; 2 0 {0 |i [1 {i fl [1 [Of fh ? {2 {0 |? [2 |2 1050 [5 38 | 2 pedipalpal tarsal claw: present; absent 0 j0 {0 /0 {O }1 {1 JI [0 {O |O JO {0 J}O JO jO }0.50 {2 39 | Leg autospasy: otherwise; at patella-tibia 0/0 {1 ]1 {1 1 f1 J) fd fd fd ft fl fi fd fi }1.00 [10 |40 | Trichobothrium metatarsus IV: present; absent 1 {0 {1 {1 }1 |1 {0 [0 _|0 0 {0 {0 |0 JO jO |0 {0.50 |3 41 | PMS: with anterior aciniform brush; without 1 }0 |1 Jl Jd ft fd fl fd fl fd ft ft fd fi fi {1.00 }10 42 | Aciniform spigots in 9 PMS: > 1; 1; absent 0 {0 |0 {0 jO |O {0 |O0 JO JO {2 |2 |1 12 [2 [2 |0.66 |10 43 | PLS mesal cylindrical spigot base: same size: enlarged [0 |o |i [1 |1 [a [a {a {a [a fa fa [a [a [a [a [1.00 [10 | 44 | PLS aciniform field: random spigots; elongated field 1 {0 {1 {1 {1 |1 Jt ft jd fi fl ae = = 1.00 |10 45 | Aciniform spigots in 9 PLS: >1; 1; absent 0 {0 |0 {0 |0 lo 0 {0 {0 |O |2 {1 46 | dspins sperm web while: above sperm web; below it ? |? [0 [0 |? 1]? position during ejaculation: above sperm web; below ? |? {0 |0 |? y |? [1 i ing directly to separate sptravies, as Millidge reported. The mentioned engonines posses i tracheal atrium (contre Millidge, 1986:57), which, using an aqueous solution of chiorazol black, stains similarly to the rest of the tracheal system, The spiracle ts most visible at both ends, where it is wider and rounded, although there is a slit connecting both emis. Such ends are not a closed circle (i.e. hey are not scparate spiracles), as Millidge’s illustrations scem to suggest (e.g, his figure 5), since they are open at its Inner parl to the interconnecting slit. Stemonyphariies blawweltae and Allomengea pinnata (Emerton) have tracheal atria opening through a single spiracle, contrary to Millidge’s assertion that in bath genera the atrium opens via two spiracles. Atria opening via a single spiracle were also found in Drapetisca alteranda Chamberlin, Centromerus sylvaticuy (Blackwall), Lep- thyphantes flavipes (Blackwall), L tenuis (Black- wall), and L. infricatus (Emerton). These latter genera were also reported by Millidge [the first one only implicitly) to have the atrium opening via two spiracles. In the two latter species the slit is very similar to the one reported here for the enigonines, with markedly wider round ends (this fact might have caused themt to be taken as having two spiracles), The spinneret spigot morphology characters (41-45) suppon the monophyly of the pimoids and of the pimoid-linyphiid clade (Honmiga, in press), Linyphiid and pimoid spigat morphology is consistent with the araneoid groundplan (Cod- dington, 1990b; Peters and Kovoor, [991]; Hor- miga, in press). The pimoid-linyphiid clade lacks the PMS aciniform brush found in primitive or- bicularians (character 41), but so do many tetrag- nathids and the theridiids. Pimoids and linyphiids share the pasition of the mesal cylindrical spigot on the penphery of the PLS, but this 3s not ex- clusive to the pinwid-linyphiid clade: tt 1s also found in Zygiella x-nerata (pers, observ.) and in some other telragnathids (Coddington, pers. comm.; Platnick et al., the base of the peripheral cylindrical spigot of the PLS (character 43) is characteristic of pimwids and linyphiids. Pimoids have drastically reduced the PMS and PLS aciniform fields (characters 42 and 45): they cither have one or none aviniform spigots on each spinneret, Stemonyphantes has also lost, presumably tn parallel, the aciniform spigots in both the PMS and the PLS. The use of the mating sequence and the transfer of sperm (characters 46-47) as taxonomic charac- ters in linyphiids was studied by van Helsdingen 1990). An enlargement of MEMOIRS OF THE QUEENSLAND MUSEUM (1965, 1969, 1983). Blest and Pomeroy (1978) studied the sexual behavior of Haplinis diloris. 1 have used data from van Helsdingen’s observa- tions as valid for the different species of Lep- thyphantes and Microlinyphia in my data, under the assumption that there is no variation for the characlers under study at the intrageneric level. For Erigone psychrophila, | have also used data from other species in the same genus, namely &. dentipelpis and E. jongipalpis (Gerhardt (1927, 1923) cited in yan Helsdingen (1983)). The male position during the construction of the sperm web (fork and web) and during ejaculation is below the sperm web in erigonines and mynoglenines, and above (only the web, the fork is constructed from below) in Linyphiini and Micronctini. ANALYSIS The data (Table 1) were analyzed using the implicit enumeration option of Hennigs6, which found four cqually parsimonious cladograms with a length of 81 steps and consistency and retention indices of 0.74 and 0.81 respectively. These four topologies differ in the interrelation- ships of pimoids and in the position of Stemanyphantes, which in one of the four cladograms is sister to the pimoids, This latier topology is the result of the paralle) loss of the acimiform Gelds in pimoids and linyphtids. Deac- tivating the characters that account for the num- ber of aciniform spigots in the PMS and PLS (42 and 45, respectively) and using the implicit enumeration option three cladograms are ob- tained. These three cladograms are the same as those obtained with the ‘active’ characters, with the exclusion of the topology that clusters Stemonyphantes with pimoids. Successive char- acler weighting (Farris, 1969; Carpenter, 1988) was used, as implemented by Hennigk6, to choose a cladogram fram the set of four equally parsimonious cladograms. A single iferation produced one cladograrn (Fig. 1), which cor- responds to one of the original set of four, This resultis stable in a second iteration. Because this cladogram ts based on the most consistent char- acters itis preferred as a hypothesis tor explaining the relationships of this sample of taxa. The eladistic analysis of this sclection of pimoid taxa produces results (i,c. tree topologies) fully con- gruent with those obtained in Hormiga (in press), in which a total of 20 pimoid species were analyzed together with the same sample of linyphiids and the two outgroup genera, PIMOIDAE AND SYSTEMATICS OF LINYPHIIDAE 537 PIMOIDAE 6 LINYPHIIDAE & a A & & & r we a) ¢ > sg $§ & & § RG Na $e Ff SC Ce EF & FSFE eC SF FC ESLFE ELSES ESESE % ~ Ae NS SF FOS SDP MWS HOH PY 29 17 30 i se |? 18 38 36 r 33 14 a he 28 8 37 32 33 17 42 Ns 27 24 ¥ 2,6,8,11, 12 ms 16,21, 45 x re 8 34 10 4 42 38 26, 40, 46, 47 14 31 45 30 40 us ; 25 3 8 8 22 19 18 23 27 41 30 37 44 7,8,14, 15, 42 22, 23, 29, 37 45 9, 36, 39, 43 FIG. 1. Preferred minimum length cladogram for the taxa and characters in Table 1 (three equally parsimonious alternative topologies exist; see text). The cladogram length is 81 steps; the consistency and retention indices are 74 and 81, respectively. DISCUSSION MOoNopPHYLY OF THE PiMoip-LINyPHIID CLADE Pimoids and linyphiids emerge as a monophyletic assemblage, unambiguously sup- ported by the presence of cheliceral stridulatory striae, patellar autospasy, and the enlargement of the peripheral cylindrical spigot base in the PLS. Paracymbial apophyses are secondarily absent (i.e. lost) in the pimoid-linyphiid clade, although they are regained in the Micronetini. All these characters (except the patellar autospasy) exhibit some degree of homoplasy. Millidge (1988) rejected the inclusion of Linyphiidae in Araneoidea, and instead related them to Agelenidae (s. /at.), Amphinectidae, and other taxa currently placed in Amaurobioidea and Dictynoidea. His hypothesis on the exclusion of linyphiids from Araneoidea has been elegantly rebutted by Coddington (1990b), who stated that linyphiids exhibit 9 out of the 10 synapomorphies that support the monophyly of Araneoidea. Pimoids share the same 9 araneoid synapomor- phies. Peters and Kovoor (1991) studied (he structure, histochemistry, and function of the spinning apparatus of Linyphia triangularix and concluded that the data did not provide any tn- dicw#tion of close relationship between Lieyphiidae and Agelenidac. Certainly Millidge's hypothesis lacks character support. The available data clearly argue in favor of the inclusion of the pimoid-linyphiid clade in Araneoidea. Furthermore, Millidge’s idiosyncratic methed of phylogenetic inference is flawed because, among other things, it seems to suggest the use of symplesiomorphies [by ‘reversing’ the outgroup comparison method) to establish family relationships (p. 254). It is well known that grouping by plesiomorphic character slales produces paraphyletic groups (Hennig, 1966) and therefore should be avoided. A major problem in araneoid phylogeny is the placement of the thendiid and the linyphiid- pimoid Jineages, in which the orb web architec- ture has been lost (Coddington and Levi, 1991)- Cyatholipidae have been suggested as another possible sister group of linyphiids (Coddington, 1990a). While the sheet web might support this hypothesis, the evidence provided by the mor- phological data 4s, at the moment, inconclusive. Mowor#y Ly of PiMoins Pimoid monophyly is supported by nine synapomorphies, six of them from male palpal morphology and two from spigot morphology. It is interesting to note that none of the pimoid- linyphiid py napamorphics refer to palpal mor- phology, which is quite different in these two lineages and might reflect a very old time of divergence and/or a rapid rate of character change for the male genitalia. The highly dezived spigot morphology of pimoids is unique among arancoids. With the exception of Stemonyphantes no other araneoids have been reported to loose all the aciniform gland spigots. Monorry.y, CHARACTER ANALYSIS, AND Cvavistic Structure oF LinyPunps Linyphiid monophyly is supported by eight synapomorphies. Seven of these cight characters (ic. all except character 8) are homoplasious. MEMOIRS OF THE QUEENSLAND MUSEUM With the increasing number of studies that use quantitative cladistic methods it is becoming clear that homoplasy is quite common (Cod- dington and Levi, 1991). Coddington (1990b) noted that many of the most useful characters for the inference of araneomorph phylogeny were homoplasious. Griswold (in press), in his study of the Lycosoidea, arrived at a similar conclusion for female genitalic characters. Linyphiids are not an exception, and this fact will not surprise most linyphiid taxonomists. For example, interseg- mental paracymbia (character 7). similar to the linyphiid type, are also found in Tetragnatha and Pachygnatha (Levi, 1981:274, 286). Millidge (1988:258) considers the two latter cases as In- tegral paracymbia, different from the linyphiid type, in which case the homoplasy would be removed from this character. Bul regardless of possible instances of homoplasy, the interseg- mental paracymbium ts a putative synapomorphy for linyphiids. Coding the paracymbial morphel- ogy (character 8) is not an easy task, I have taken a conservative approach by coding it with a high number of character states (seven), in part due to the high morphological diversity of this structure, The coding used produced no extra length (the character’s consisiency index is 1), but by itself it provides little grouping information (only Kvo states occur in more than one taxon), The states are thus ‘ordered’ by the tree topology generated by all characters (the final optimization of the character on the cladogram was done by hand, because several equally parsimonious optimiza- tions exist). Blest (1979) and Wunderlich (1986) consider that mynoglenines and erigonines share the same type of paracymbium (‘simple paracymbium’). Van Helsdingen (1986:122) ar- gued against this view by pointing out thal many linyphiine genera also haye the so-called ‘simple’ paracymbium. Although in some cases erigonines and mynoglenines seem to have moe- phologically ‘simpler’ paracymbia (short proximal and distal branches, sometimes J- shaped, without apophyses) than some of the linyphiini and micronetini, I cannot see a clear- cut distinction between these two states. I have coded all the linyphiids (except Stemonyphanies) as having the same overall paracymbium mor- phology (with a proximal and a distal branch of varying length and being more or less J or U- shaped). The paracymbium type found in Stemonyphantes is considered by Millidge (1988) as an Intermediate form between the integral and inlersegmental types. This latter type of paracym- bium is inferred to be the primitive state for PIMOIDAE AND SYSTEMATICS OF LINYPHITDAE linyphiids, This state is subsequently transformed into the paracymbium morphology found in the rest of linyphiids, Coding mynoglenines and erigonincs as sharing the same unique character state (i.¢., the ‘simple’ paracymbium), as Blest and Wunderlich have soggested, produces no changes in the cladogram topology. The presence of a median apophysis and a conductor on the tegulum is regarded as plesiomorphic for araneoids (Coddington, 1990a). Pimoids have a conductor and a median apophysis (Hormiga, in press). The absence in linyphiids of a true (i.e. tegular) conductor and a median apophysis (Coddington, 1990a) are regarded as synapomorphies for linyphiids (char- acters 15 and 14, respectively). Two potential synapomorphies of linyphiids, the radix and the column, are waiting forresolution of the oulgroup of the pimoid-linyphiid clade in order to be tested. The linyphiid radix (character 22) might be homologous to the araneid radix, and therefore plesiomorphic for linyphiids, if araneids are the sister group of pimoid-linyptiids (Coddington, 1990a). The same happens with the linyphiid column or stalk (sensu Saaristo, 1971; character 23) that connects the radix to the tegulum/suprategulum. The column could be homologous to the distal haematodocha if arancids are sister to the pimoid-linyphiid clade (Coddington, 1990a), If that is not the case, the homology of the linyphiid radix and column with ils presumed equivalents in Araneidace might be refuted, and these characters would function as synapomorphics of linyphiids (this latter alterna- live is the one mapped on Figure 1). Linyphiids seem to have reduced the number of prolateral trichobothria in the male palpal tibia (character 29) from two (pimoids and outgroups in the data set) to one. However this putative synapomorphy of linyphiids might loose generality (i.e. might be refuted) in a data set with a larger sample of taxa. The same might happen te the number of retrolateral teeth on the female chelicera (charac- ter 37), which is four or more in all but one of the linyphiid taxa in the data set, and acts as putative synapomorphy for linyphiids. The linyphiid suprategulum (character 13) isa projection of the tegulum that bears the column and through which the sperm duct passes (Saaris- to (1971, 1975); Millidge (1977); Coddington (1990a)). However. the suprategulum might not be homologous across all linyphiids. The tegular projection thal Blest (1979, figs 596-602) and Blest and Pomeroy (1978, figs 2, 4) call the ‘suprategulum’ in New Zealand mynoglenines 5349 does not bear the column (wiuch in some cases 15 far from it, e.g. Pseudafroneta, in Blest’s figure 597) and has no sperm duct going through it. | have interpreted the mynoglenines as lacking a suprategulum (serisu Saaristo) and coded its tegular apophysis as a structure synapomorphic for mynoglenines and not homologous to the suprategulum (‘mynoglenine tegular apophysis', character 12). However, the tegular apophysis of Haplinis seers 1o be functionally analogous to the suprategulum in some linyphiids (van Helsdingen (1965, 1969); Blest and Pomervy (1978)) in engaging the socket of the epigynal scape, but data on the functioning of the genitalia across taxa are still very scarce. The suprategulum of Stemonyphantes is articulated to the tegulum by means of a membranous connec- tion (van Helsdingen, 1968-124; pers, observ.) and is different from the rest of linyphiid suprategula which are fused to the tegulum (char- acter 13). The cladogram in Figure 1 suggests the possibility of independent origins for these wo types of suprategula, and therefore questions its homology (secondary absence of the supralégulum in the mynoglenines -versus inde- pendent gains-requires one additional step). The linyphiid embolic membrane (van Heisdingen, 1969) is not homologous to the arancoid conductor because of their different position (but see Coddington, 1990a:16). The embolic membrane (character 18) is a putative synapomorphy for all linyphiids, with the ex- clusion of the basal genus Sremonyphantes. The ‘embolic membrane’ Microlinyphia is not an out- growth of the column, as in most Jinyphiids (van Helsdingen, 1986:123), but a structure ‘arising from (the) membranous connection of radix, base of embolus, and dorsal side of lamella! (van Helsdingen, 1970-6). I have interpreted it as not hemologens to the column-positioned embolic membranes, but the nature of this membrane remains dubious- The alternative, i.e. coding it as an embolic membrane shifted to a radical position in Micralinyphia, produces no change in the cladogram topology. The terminal apophysis (character 25) is a synapomorphy for erigonines plus linyphiines, butits interpretation offers several problems. The firstis its homology with its homonym in araneids (Saaristo 1971, 1975; Coddington, 1990a), Such homology 1s dependent, among other things, ona sister-group relationship between araneids and linyphiics (plus pimoids), but even sa the homol- ogy is not obvious. Zygiella x-notata (which 1s considered here as an araneid) lacks anything 540 similar to a terminal apophysis, pimoids lack the radix (therefore, we do not know if they ever had such apophysis), and basal linyphiids (i.e. Stemonyphantes and the mynoglenines) have simple radices and no terminal apophysis. The cladogram in Fig. 1 suggests independent origins (i.e. non homology) for the terminal apophysis in araneids and linyphiids. If the embolic division of Stemonyphantes is interpreted as simple (and not simplified) it also suggests that complex embolic divisions in araneids and in linyphiids arose inde- pendently. This latter interpretation would ques- tion the monophyly of araneids plus linyphiids (e.g. Coddington, 1990a:14). Second, and at a less inclusive level, not all erigonines and linyphiines have a terminal apophysis. Evalua- tion of the homology of these apophyses requires a more detailed cladistic structure for the family (i.e. more taxa and more characters). Another radical sclerite, the lamella characteristica (char- acter 26), is a putative synapomorphy for the linyphiines. Further support for the monophyly of Micronetini plus Linyphiini is given by the loss of metatarsus IV trichobothrium (character 40) and the position of the male during the construc- tion of the sperm web and during ejaculation (characters 46 and 47). The phylogenetic infor- mation provided by the latter two characters should be regarded as provisional, because of the high number of missing entries for these charac- ters in the matrix. According to Blest and Pomeroy (1978) Haplinis is unique among linyphiids in having an expansion of the palp prior to its locking to the female genitalia, while in the remaining linyphiids for which this trait is known the male first locks its palp to the epigynum and then expands the haematodocha. However, in a recent study on African linyphiids Scharff (1990:62) described a similar expansion prior to locking for Neriene kibonotensis (Tullgren). More data on the distribution of this character are needed in order to establish it as a mynoglenine synapomorphy. Erigonine monophyly is supported by the retrolateral tibial apophysis of the male palp, the loss of the female palpal claw, and the des- mitracheate tracheal system (sensu Millidge, 1984). In the present dataset the epigynal atrium (character 33) is the only synapomorphy support- ing the monophyly of Linyphiini. An epigynal atrium is also present in the mynoglenine genus Haplinis (Blest, 1979:100) but absent in Novafroneta (Millidge 1984:241). The cladogram suggests independent origins for these two atria; its homology is therefore questionable MEMOIRS OF THE QUEENSLAND MUSEUM (similar epigynal atria are also present in other linyphiids, not included here, that are not closely related to the Linyphiini; Millidge, 1984; van Helsdingen, in litt.). Three synapomorphies sup- port the monophyly of Micronetini: the paracym- bial apophyses, a short embolus (it also occurs in Erigone), and the presence of Fickert’s gland in the radix. The nature of the clypeal glands is another interesting problem in linyphiid evolution. Whether the mynoglenine sub-ocular sulci are or are not homologous to the male erigonine post- ocular sulci is a matter of debate. Mynoglenine sub-ocular sulci are found both in males and females (they are very similar in both sexes; juveniles also have functional sulci, at least in the species of Haplinis studied by Blest and Taylor, 1977), they do not play any active role during the courtship (at least in the species studied by Blest and Pomeroy, 1978), and they probably elaborate defensive secretions (Blest and Taylor, 1977; but this latter hypothesis has not been empirically tested, although the unique ultrastructure of the clypeal secretory cells is consistent with the syn- thesis of a toxic product). On the other hand, erigonine post-ocular sulci (as well as the cephalic elevations) are found (mostly) in adult males. These erigonine sulci usually have pores associated with glands that are cytologically dif- ferent from those of the mynoglenine sulci (Blest and Taylor, 1977; Schaible et al., 1986; Schaible and Gack, 1987), and they play an active mechanical role during the courtship (they are gripped by the female cheliceral fangs). Never- theless, these erigonine glands are not always associated with cephalic specializations. Mynoglenine and erigonine ocular sulci can be interpreted as homologous structures within the same transformation series or as two independent developments. The available evidence is not easi- ly interpreted in either way. The mynoglenine and erigonine sulci differ in their position, in the cytological structure of their associated glands, and in their behavioral role. It seems that the available data argue against the homology hypothesis, since they fail to meet the classical homology criteria of position and detailed similarity. Congruence with other character sys- tems offers a powerful test of the homology hypothesis of the sulci. Blest (1979:165) argued that the most economical hypothesis (i.e. par- simonious) ‘would suggest that the sulci of the mynoglenine type gave rise directly to the kind found in Erigoninae’. Mapping his hypothesis on his cladogram (op. cit., p. 172, which in parenthi- PIMOIDAE AND SYSTEMATICS OF LINYPHIIDAE cal notation can be summarized as: Mynogleninae (Linyphiinae, Erigoninae)) re- quires the gain of the mynoglenine type of sulci in the common ancestor of all linyphiids, profound modifications (morphological, cytological, and behavioral) of the sulci to achieve the erigonine type of sulci (either in the ancestral erigonines or at the level of the linyphiine-erigonine ancestor) and finally the Joss of the sulci (and its accompanying glands and behavior) in the linyphiines, The alternative hypothesis (i.c. non homology of mynoglenine and erigonine sulci) maps on the mentioned cladogram as two independent gains of the two types of sulci. The evolution in parallel of the erigonine and mynoglenine sulci would then ac- count for their differences. Although the latter hypothesis is more parsimonious (in both Hlest’s and my cladogram) this question cannol be truly tested until more data (taxa, particularly those with any type of sulci and/or glands, aid infor- mation on the giands) are included im the data set. This is due to the effect that mynoglenine and erigonine cladogram topologies might have on the optimization of the character(s) on the linyphiid cladogram. Only then we will be able to asses alternative hypotheses on the evolution of these cephalothoracic specializations. The linyphiid tracheal system needs to be studied in detail and re-evaluated, New mor- phological descriptions are needed, since at least some of the available comparative data are inac- curate (see above), Millidge's (1986, figure 12) scheme for the evolution of the tracheal system in linyphiids is therefore not valid, because it 1s partially based on inaccurate data. The most parsimonious hypothesis to explam the data presented in this study is the cladogram depicted in Figure 1, which suggests (as well as the three equally parsimonious alternatives that exist) relationships different from those proposed by Wunderlich (1986:106). The mynoglenines are considered here to be relatively basal linyphiids, while Wunderlich suggested them as sister to the erigonines. Both hypotheses agree on considering the pimoids and Stemonyphantes as the most basal clades, and on the monophyly of the Micronetini plus the Linyphiini. To use either of these two phylogenies asa classification would be premature. Wunderlich did not explicitly list the synapomorphies that define the monophyletic groups in his cladogram, synapomorphies are mixed up with diagnostic characters (some of which are not synapomorphic), and there is no mention of the genera included in each monophyletic group, evenin aschematic manner, My study should be considered only a prelimi- nary sketch of linyphiid relationships. Clearly, a much larger sample of taxa is needed before the main monophyletic groups can be established, The addition of new taxa and new characters might affect the cladogram topology presented here. As we have seen, non-homoplasious char- acters for wide ranges of taxa are more the excep- tion than the rule, and different character systems. often delimit conflicting monophyletic groups, When large numbers of taxa and characters are studied quantitative studies are imperative, Cladistic studies provide explicit and testable hypotheses of relationship and aré recognized as the most reliable method for retrieving the phylogenetic pattern thal underlies organic diver- sity. Not until this approach is adopted will ad- vances in linyphiid higher classification become a reality. ACKNOWLEDGEMENTS I am indebted to Drs. J_A_ Coddington, C. Mit- ter, CE. Griswold, N-L Plamick, and N. Scharff forhe]pful discussion and comments on an earlier version of this manuscript. Financial support for this study was provided by the University of Maryland and the Smithsonian Institution. LITERATURE CITED BLEST_ A.D. 1979. Linyphiidae-Mynogleninae. Pp. 95-173, In RR, Forster and A.D. Blest, The spiders of New Zealand, part V. Otago Museum Bulletin 5: 1-173. BLEST A.D. & POMEROY. G. 1978. The sexual he- haviour and genilal mechanics of three species of Mynoglenes (Araneae: Linyphiidae). Journal of Zoalogy (Landon) 183: 319-340. BLEST A.D. & TAYLOR, H.H. 1977. The clypeal glands of Mynoglenes Simon and some other Jinyphiid spiders, Joumal of Zoology (Landon) 183: 473-493. CARPENTER, J.M, 1988 Choosing umong multiple equally parsamonious cladograms, Cladistics 4 291-296. CODDINGTON, J.A. 1989. Spitinerct silk spigot mor- phology: evidence forthe monophyly of orbweave ing spiders, Cyttophorinae (Arancidae), and the group Theridiidac plus Nesticidae, Journal of Arachnology 17: 71-95. 1990a, Ontogeny and homology in the male palpus of orb-weaving spiders and their relatives, with comments on phylogeny (Araneoclada: Arancoidea, Deinopoidea), Smithsonian Con- tnbutons to Zoology 496; 1-52. 1990b. Cladistics and spider classification: 542 Araneomorph phylogeny and the monophyly of oroweavers (Araneae: Aranemorphac; Or- biculariae). Acta Zoologica Fennica 190: 75-87. COBDINGTON, J.A. & LEVI, H.W. 1991. Sys- tematics and evolution of spiders (Araneae). An- nual Review of Ecology and Systematics 22: 4565-592. FARRIS, J.S. 1969. A successive approximations ap- proach lo character weighting. Systematic Zool- ogy 18: 374-385. (988, Hennig&6, version 1.5, (Computer program distributed by its author, 41 Admiral Street, Port Jeflerson Station, NY 11776). GRISWOLD, CE, (in press), Investigations imto the phylogeny of lycosoid spiders and their kin (Arachnida, Araneae, Lycosoidea), Smithsonian Contributions to Zoology. HENNIG, W. 1966. ‘Phylogenetic Systeniatics'. (University of Mlinois Press: Urbana). 263pp. HORMIGA, G, In press. A revision and cladistic analysis of the spider family Pimoidae (New Rank, Araneoidew, Araneac). Smithsonian Con- tribvotions to Zoology LEVI, H.W. 1981. The American ofb-weaver genera Delichoenatha and Tetragnatha nonh of Mexico (Araneae; Araneida, Tetragnathinae), Bulletin of the Mustum of Comparative Zoology 149: 271- 318, MILLIDGE, A.F. 1977. The conformation of the male palpal organs of Linyphiid spiders and its applica- lion to the taxonomic and phylogenctic analysis of the farmily (Araneae: Linyphiidae). Bulletin of the British Arachnological Society 4; 1-60. 1984. The taxonomy of the Linyphiidae, based chiefly on the epigynal and tracheal characters (Arancac: Linyphiidae). Bulletin of the British Arachnological Society 6; 229- 267. 1986, A revision of the tracheal structures of the Linyphiidae (Araneae), Bulletin of the British Arachnylogical Society 7: 57-61. 1988. The relatives of the Linyphiidae: phylogenetic problems at the family level (Araneae). Bulletin of the British Arachnological Society 7:253-268. PATTERSON, ©. 1982. Morphological characters and homology. Pp. 21-74. In Joysey. K.A. and Friday, A.E. (eds) ‘Problems of Phylogenetic Reconstruction”. (Systematics Association Spe- cial Volume No. 21, Academic Press: London and New York), PETERS, H.M. & KOVOOR, J. 1991. The silk-produc- ing system of Linyphia triangularis (Araneae, Linyphiidac) and some comparisons with Araneidae. Structure, histochemistry and fune- tion. Zoomorphology 111; 1-17. PLATNICK, N,L, CODDINGTON, J.A., FORSTER, R.R. & GRISWOLD, C.E. 1991. Spinneret mor- phology and the phylogeny of haplogyne spiders MEMOIRS OF THE QUEENSLAND MUSEUM (Araneae, Arancomorphac), American Museum Novitates 3016; 1-73. SAARISTO, M.1, 1971, Revision of the genus Maro O.P.-Cambridge (Araneae, Linyphiidae). Annales Zoologici Fennici 8: 463- 482. 1975, On the evolution of the secondary genital organs of Lepthyphantinae (Araneae, Linyphiidae), Proceedings of the 6th Internation- al Arachnological Congress (Amsterdam, 1974): 21-25. SCHAIBLE, U. & GACK, C. 1987. Zur Morphologie, Histologie und biologischen Bedeutung der Kopfstrukturen einiger Arten der Gattung Diplocephalus (Araneida, Linyphiidac, Erigoninae). Verhandlungen des Naturwis- aesesepattncied Vereins in Hamburg 29: 171- 180, SCHAIBLE, U., GACK, C. & PAULUS, HLF. 1986. Zur Morphologie, Histologie und biologischen Bedeutung der Kopfstrukturen miinolicher “Zwergspinnen (Linyphiidae: Erigoninae). Zoologische Jahrbiicher (Systematik) 113(3): 389-408, SCHARFF,N. 19%). Spiders of the family Linyphiidae from the Uzungwa mountains, Tanzania (Araneae). Entomologica Scandinavica, Supple- ment No. 36: 1-95. VAN HELSDINGEN, P.J. 1965. Sexual behaviour of Lepthyphaniey leprosus (Ohlert) (Araneidae: Linyphiidac), with notes on the function of the genital organs, Zoologische Mededclingen (Leiden) 41; 15-42. 1968. Comparative noles on the species of the holaretic genus Sremonyphantes Menge (Araneida, Linyphiidae). Zoologische Mededelingen (Leiden) 43(10): 117-139. 1969. A reclassification of the species of Linyphic Latreille, based on the functioning of the genitalia (Araneida, Linyphiidac) . Zoologische Verhan- delingen (Leiden) 105; 1-303 1970. A reclassification of the species of Linvphia Latreille, based on the functioning of the genitalia (Araneida, Linyphiidae) Il. Zoologische Verhan- delingen (Leiden) 111: 1-86. 1983, Mating sequence and transfer of sperm as a taxonomic character in Linyphiidae (Arachnida: Araneae). Verhandlungen des Naturwis- sensschafilichen Vereins in Hamburg 26; 227- 240. 1986. World distribution of Linyphiidae, Pp. 121- 126. In Eberhard W.G., Lobin Y.D., Robinson B.C. (eds) ‘Proceedings of the Ninth Internation- al Congress of Arachnology, Panama, 1983", (Smithsonian Institution Press: Washtngton, D.C.). WUNDERLICH, J. 1986. “Spinnenfauna geste und heute”. (Erich Bauer Verlag bei Quelle and Meyer: Wiesbaden). CRITERIA FOR IDENTIFYING THERMAL BEHAVIOUR IN SPIDERS: A LOW TECHNOLOGY APPROACH W.F. HUMPHREYS Humphreys, W.F. 1993 11 11: Criteria for identifying thermal behaviour in spiders: a low technology approach. Memoirs of the Queensland Maseum 33(2): 543-550. Brisbane. ISSN 0079-8835. ‘The widespread occurrence of thermal behaviour in diurnally active web spiders is cither largely ignored or not recognised, Thus it obfuscates some explanations of the function of the stabilimentum on spiders webs. Thermal behaviours of four spiders (Nephila edulis, N. maculata, Gasteracantha minax and Neogea sp.) are examined using technology which is often inappropriate for field studies, Many thermal behaviours are recognised as well as behaviours which Facilitate thermal behaviour. The thermal correlates of these behaviours are established. Some observational criteria are derived, which require only simple equip- ment, by which thermal behayiours may be recognised in the field and distinguished from other behavioural patierns.CArancae, orh-weavers, thermal behaviour, thermoregulation, stabilimentum. W.F. Humphreys, Western Australian Museum, Francis Street, Perth, Western Australia 6000, Australia; 26 October, 1992. Many orb-web spiders remain active at the web hub during the day. where they can continue to feed, mate, and defend their web site from the same and other species, as well as produce or respond to attractant signals (acoustic, tactile, visual or chemical). The seasonal and diurnal duration of this activity can be extended by adopt- ing behaviours that warm the spider (Robinson and Robinson, 1974, 1978; Biere und Uetz, 1981) when it would otherwise be too cold or else that prevent it from overheating (Lubin and Henschel, 1990; Humphreys, 1978, 1987a, 1991, 1992). I consider below mainly behaviours that prevent overheating. In essence, in hot weather the spider postures so as to align the long axis of its body with the sun’s rays and in this position it tracks the sun’s apparent movement during the day. Such behaviour is not exclusive to spiders of open country nor in tropical climates but is found also in both temperate and tropical forest spiders (Biere and Uetz, 1981; Humphreys, 1991, 1992 and unpublished). The standard interpretation of this thermal behaviour relies on a simple physical model; posturing minimises the projected surface areca (silhouette) exposed to the sun’s radiation and so reduces the heat load (Fig, 1), lowenng equilibrium body temperature (Willmer and Unwin, 1981: but see Humphreys, 1986) or, in an anu-predator hypothesis, minimising the sil- hovette against the brightest background, else the body area most brightly illuminated. Recent observations haye shed some light on this seemingly simple process and revealed a sequence of behaviours serving to reduce pro- gressively the heat loading, behaviours that are themselves mostly graded (Humphreys, 1992). These include stilting, drooping, orientation. front leg raising, abdomen pointing, posturing, front leg rotation and web abandonment. As- sociated behaviours include silk laying and agita- tion (Humphreys, 1992 and unpublished), In addition, the use of a dise stabilimentum as a sun shade, suggested by Robinson and Robinson (1973: 283), is an effective thermal behaviour in Neogea sp. (Humphreys. 1992), Such behaviours not only maintain the animal within its heat tolerance range, but also serve to maintain the body temperature (Tp) within a narrow range (presumably some optimum temperature) for ex- tended periods of time (Humphreys, 1974, 1978, 1991). As body temperature has wide implica- tions in physiological, behavioural, ecological and evolutionary contexts (Willmer, 1991), it is important to recognise thermal behaviour in spiders in order to allow different types of ex- planations for their behaviours. That the thermal behaviour of spiders is not being recognised or is not being reported in the literature can be drawn from work on stabilimen- ta on spiders” webs. While stabilimenta have many different forms, they are mostly thought to provide mechanical support (Robinson and Robinson, 1973), to function as anti-predator devices. (Eberhard, 1973, Edmunds and Ed- munds, 1986; Lubin, 1986), to attract prey (Ewer, 1972; Craig and Bernard, 1990) or to collect water (Olive, 1980; see also Ewer, 1972; Robin- san and Robinson, 1973: 283), Neogea sp. in Papua New Guinea uses a disc stabilimentum as a parasol, which, together with a sequence of other behaviours, cach themselves graded, reduces its heat loading (Humphreys, 1992). The demonstration that stabilimenta may be used ina thermoregulatory role raises questions concem- ing many observations which have been inter- preted as supponing the anti-predator role of stabilimenta. Some observations and deductions have resulted in an anti-predator function being ascribed to the stabilimentam, However, in the absence of other information, these observations are equally open to interpretalion in terms of thermoregulatory hypotheses (see Humphreys, 1992). For example -1. Only spiders that remain ut the hub of the web during the day produce stabilimenta (Eberhard, 1973). 2. Spiders with stabilimenta may shuttle from one side of the web to the other (ibid.). 3. The legs assume-an “aligned posture’ by day but not by night (ébid.), 4. The amount of silk used is directly related to openness of the habitat (Marson, 1947), Eberhard (1973) found that Uloberus diversus Marx used more silk in its stabilimentum on light than on dark nights (see also 4, above). The trend for larger stabilimentum at brighter sites camouflaged those spiders most susceptible to attack. However, without pertinent behavioural data, it is not possible lo refute the hypothesis that the open sites are More exposed to direct sunlight and thus that the stabilimenta are ased to protect the spider from ultra violet light (but see Craig and Berard, 1990) of to reduce its heat load. Posturing by spiders that remain by day at the web hub is rarely mentioned in the literature on stabilimenta and defense mechanisms, For ex- ample, although Edmunds and Edmunds (1986: §3) found that species of Argiope, Nephila, Leucauge, Cyrtophora and the Gasteracanthinac remain at the hub of the web during the day, they made no mention of posturing. In the Australasian region species in all these genera readily posture and track the sun (Humphreys, 1991, 1992: W.F. Humphreys. unpublished). Clearly, thermoregulation hypotheses need more consideration in field studies of diurnally active spiders. More recently this has occurred (Henschel et al., 1992; Humphreys, 1991, 1992; Lubin and Henschel, 1990; Ward and Henschel, 1992) but such studies often require expensive equipment to examine the thermal behaviour. Such equipment may be inappropriate to a field biologist primarily interested in ohseryation and manipulation to examine behavioural ar MEMOIRS OF THE QUEENSLAND MUSEUM sociobiological problems. There needs ta be some observational criteria using only low tech- nology by which thermal behaviour may be recognised and distinguished from other be- havioural patterns. The examination of thermoregulation in orb- weaving Spiders is problematical as most methods used on vagrant spiders (thermal preferendum apparatus, thermocouple implanta- tion, temperature transmitters) are not ap- propriate. The most promising apparatus for such studies is the use of remote infrared telemetry (Suter, 1981; Humphreys, 1991, 1992), although model spiders may be effectively used to deter- mine Te (Riechert and Tracy, 1975; Henschel e¢ al,, 1992), Can criteria be established which would enable workers, using cheap and readily available equip- ment, to establish that spiders are behaving in a manner consistent with thermoregulation and to identify the thermal conditions under which they initiate such behaviour? METHODS Observations on Nephila edulis (Labitlardiére) were made both on Rottnest Island and in Perth, on Gasteracantha minax Thorell in the south- west, of Western Australia, and on Nephila maculata (Fabricius) in mangrove at Port Benoa, Bali, Indonesia, Spider temperatures Were recorded from 1100 -1500 hours using an infra-red thermometer, described elsewhere (Humphreys, 1991, 1992). The temperature was recorded of undisturbed spiders resting above and below the hub of the web, both in the shade and in the sun, Tt was recorded at intervals and as soon as possible (<3s) after a change in behaviour. Spider behaviour changed according to the incident light; this varied because the site was sometimes shaded by trees or by clouds. To induce more behavioural sequences the spider was sometimes shaded ar- lificially and the direction and strength of the incident sunlight adjusted using a mirror. A plane mirror was used to alter the apparent position of the incident radiation at about the same intensity as the natural sunlight and a concave mirror was used to alter the apparent position of the incident ra(liation and at an intensity continuously vari- able trom greater to less than the intensity of the direct sunlight. In the field, control of intensity Was crude in the wind owing to movement of the web, and hence the spider; control of the intensity THERMAL BEHAVIOUR IN SPIDERS eneveer —_{aisn_fs._[n_{ Range _ Reposeinshude [32.64 2.0 12 __|29.0-35.1 | [Repose in partial som |a24ah [159 [19 | 79.9-343 | [Bepos nn “50 jis |47__ [316-3853 | TABLE 1, Mean temperature (Tp °C) of N. edulis in Repose position on Rottnest Island, Western Australia. Tp of spiders in Repose differs according io energy intensities of their location (shaded, partly shaded, sunlight! ANOVA - Fs 275 = 19.895, P<0.001 ), Common letters include means not differ- ing significantly (Fisher's PLSD at w= 0.05). of radiant energy is therefore relative and greater or Jess than the natural incident radiation. The following temperatures are mentioned: Ts = of ambient shaded air; Ty = of the spider *s body which by default is the abdomen (Tap), otherwise the thorax (Tw). The environmental temperature (T,) which is used as a shorthand for the effective heat load on the spider taking account of all energy gains and losses. Means are followed in parentheses by the standard deviation of the mean, and sample size, Definitions required for this discussion are given below (see also Humphreys, 1991, 1992), Abandon web: the spider leaves the web, often after a sequence of very agitated movements, and moves to the shade provided by the objects to which the main anchor lines of the web are attached. Abdomen pointing: Ihe abdomen alone is oren- tated to the sun as 4 prelude to full posturing. This behaviour is strongly represented in some species (Humphreys, 1992), Agitation and body lift: the spider appears agitated and circles its body around the web's hub and in the process the body is raised away from the web. ‘The latter 1s sometimes seen on its own and they are included here under the same behaviour. This body liftis not comparable to stilting (Humphreys, 1992), Prooping: the spider hangs limply from the back legs with apparent loss of hydrostatic pressure; the appearance is like that adopted by a spider imme- diately after moulting while the new cuticle is hardening. Fabian position (Humphreys. 1991): the spider aligns its Jong axis parallel to the direction of incident sunlight with the prosoma facing away from the sun. This position may be achieved by orientation and/or posturing. When the incident sunlightis parallel to the web plane then the Fabian position may be the same as the Repose position (Humphreys, 1991). Continued adoption of the Fabian position results in the long axis of the spider tracking the sun during the day. front legs raised; legs 1 and IL are raised off the web and aligned parallel to the incident radiation; this occurs as a graded sequence with the first pair beig raised before the second pair. Orientation: the angle of the saggital plane of the spider is rotated to Iie parallel to the solar azimuth while the long axis of the body stays in the plane of the web, Part orientation: the spider is not in the Repost: position and has partly orientated its saggital plane between the Repose position and the orientated position Pesturing: change in the angle between the web plane and the antenor-posterior axis of the spider. Repose position: spiders occupy the lower or upper surface of the hub with the prosoma pointing downwards; the anterior-posterior axis. of the spider is parallel to the plane of the web. Rotate fronr legs: following front legs raising the legs are rotated forwards such that they are stretched out in front of the spider and lie in the shade of its body when itis fully postured; this may occur as a graded sequence with the tirst pair being rotated before the second pair. Silk laying: adjusts the web stuctrure near the hub apparently to aid leg placement the better to pos~ ure and orientate to achieve the full Fabian posi- tion. This facilitates subsequent thermoregulatory behaviour but is not itself thermoregulatory. Startte posrare: when the spiderchanges the angle between its antero-posterior axis and the plane of the web such that its long axis is parallel to the incident radiation. Stilting: descnbes the ‘standing on tiptoc’ be- haviour of scorpions used to prevent overheating (Alexander and Ewer, 1958); here it describes similar behaviour in spiders (Humphreys, 1992). EVIDENCE Statements otherwise unsupported are based on my unpublished observations, REPOSE POSITION AND THERMOREGULATION Spiders adopt the repose position if Te is below some critical level and they do so whether they are in shade or sun, hence, direct sunlight alone does not cause spiders to posture, However, Tsin sun is higher than in shade (Table 1). For cx- ample, during ceol weather (low Tz) in the sun and during hot weather in the shade all in- dividuals are in the Repose pesition on their webs if not otherwise engaged in activities such as mating, web building, etc. When Ty is not sufficient to cause posturing in G. ninax the proportion of spiders in the Repose 546 position during daylight does nor differ between sunlit (36/38) and shaded (32/33) sites (x 7) = 0.016, P= 0,90), The mean Ts temperature of N. edulis in the Repose position was directly related to the inten- sity of the incident radiation such that spiders in the sun were hotter than partly or fully shaded spiders (Table L). Spiders on non-horizontal webs almost invariably rest on the underside of the web with the prosoma pointing down. However, spiders resting in posi- tions other than the Repose position should not be taken as proof of thermoregulatory behaviour be- cause some species, such as Verrucesu and Cyclase, reputedly adopt a head up stance (Foelix, 1982: 139), as does G, minax at night aad Ar- gyrades antipodianus O.P. Cambridge, generally. ORTENTATION AND PosTURING: EvInENce FOR ‘THERMOREGULATORY FUNCTION In hot weather, spiders orient or posture on the web to attain the Fabian position and then track the sun's apparent movement. They do this ir- respective of web orientation. Heat and sunlight are needed to obtain these behaviours, On very hot days, spiders may leave the web altogether and seck shade, Large spiders assume Fabian posture earlier than small ones possibly because under given environmental conditions large spiders reach higher body temperatures. How- ever, small spiders may have lower threshold Tp’s. In hot weather an indj\idual spider in the sun will use reorientation and/or posturing to align the anterior-posteror axis of its body parallel to the direction of incident sunlight with the prosoma facing away from the sun and thus achieve the Fabian position (Robinson and Robinson, 1974, 1978; Humphreys, 1991, 1992), The spider will adjust this position during the day and track the apparent movement of the sun (Humphrey's, 1991), Tn hot weather all individuals in the sun orientate inthe same direction irrespective of the orientation of their webs; namely they all assume the Fabian position by posturing and/or reonentation (Humphreys, 1991). Heat alone does not cause the thermal behaviour because in hot weather under heavily overcast conditions spiders do not assume the Fabian posi- tion. However, if intermittent direct sunlight strikes the spider it assumes the Fabian position imtermiltently, On very hot days spiders may assume the Fabian position in the morning and aflemmoan but leave the web to seek shade during the middle of the day. MEMOIRS OF THE QUEENSLAND MUSEUM Such activily pattems have been reported for many heliothermal spiders (Humphreys, 1978, 1987a, 1987b) and other taxa (e.g. reptiles: Heatwole, 1970). N. edulis abandons the web at 44.8°C (+0.50, 3) and moves into shade. In Perth, Western Aust- calia, when the shaded air temperature was extreme (46.2°C) many N. edulis failed to seek cooler places and fell dead from their shaded webs through heat stress (G.A. Harold, pers. comm., 1991). Large spiders assume the Fabian posityon easlier in the day than do small spiders (e.g., N. mtaculata)}— this is consistent with the thermoregulation hypothesis because larger bodies have a higher temperature excess (Willmer and Unwin, 1981). However, the threshold temperatures. for given behaviours could be size related and lower in small than in Jarge spiders. This is consistent with the seeming generality that the tolerance zones of animals are related to the temperatures ex- perienced. For example, very small N. edulis start to posture at 36.0°C (=2.39, 4), significantly cooler, by an average of 4.4°C (Fs) 25. =13.279, p=0).002), than adult spiders undergoing the same behaviour (40.4°C 42.16, 27). ORIENTATION AND PoSTURING IN RESPONSE TO MANIPULATION Experiments with redirected and intensified sunlight can be conducted to influence the be- haviour of spiders to assist in determining whether the behaviour is thermoregulatory without having to measure body temperature. The results are consistent for several species includ- ing Arachnura higgins, N. edulis, N. maculata, G. minax and Neogea sp. In cool sunny weather when the spiders are in the Repose position, additional heating (by con- centrating redirected sunlight using a concave mir- ror}, results in the spider orientating—and/or posturing if necessary—to assume the Fabian posi- ion. The redirected sunlight does not alone alter the behaviour of the spider (sunlight redirected at natural intensity using a plane mirror). Hence, posturing is dependent on the intensity of the heat applica. In hot weather a spider which has assumed the Fabian position will resume the Repose pasition if clouds obscure the sun or it is artificially shaded even if lower than the natural insolation is reflected onto jt by means of a concave mirror. Spiders in the Fabian position in the sun will, if artificially shaded, assume a new Fabian position THERMAL BEHAVIOUR IN SPIDERS 147 FIG, 1. Thermoregulatory postures adopted by golden web spider, N, clavipes, Lines projecting from three successive positions of sun (S/, $2, 53) indicate corresponding orientations of long axis of spider's body, Lateral views (a,c) and plan view (b) of web show posture assumed in response to ventral (through the web) insolation; b lateral insolation; c dorsal insolation (redrawn from Robinson and Robinson, 1974). if the direction of the sun is artificially changed by means Of a mirror, In hot weather when the spiders are in the Repose posiuion in the shade, redirection of unconcen- trated sunlight, by means of a plane mirror or 4 concave mirror, results in the spider orientating and/or posturing if necessary to assume the Fabian position. In hot weather, when the spiders are in a Fabian position, adding reflected sunlight from a plane mirror results in the spider orientating with respect to the mean angular direction of the two sources of incident radiation (when angle <90°). A spider posturing between [wo heat sources will turn to- wards the one increased in intensity and vice versa. Hence, the Fabian position moves towards the incident radiation of the mirror if the heat reflected from the mirror is increased and towards incident radiation of the sun if the heat reflected from the mirror is decreased. If redirected light comes from above the horizontal plane of the web spiders rapidly change their Fabian position; if redirected light comes from below the horizontal plane of the web, a naturally impossible position, spiders appear confused and change position frequently and some species never achieve the Fabian position (e.g. . maculata). CASCADING BEHAVIOURS Many thermally related behaviours that have been categorised are themselves graded so that they each develop progressively rather than switch from one state to another. For example as Neogea sp. warms in the sun, it exhibits a progression of distinct behaviours, each of which is graded and which are associated with increasing temperature of the abdomen (Humph- reys, 1992), When a spider in the Repose position on the disc stabilimentum is heated by the sun it initially ‘stilts’, as has been described for scor- pions. The spider gradually raises its body away from the disc surface until it has full downward extension of all legs and seems to be standing on ‘uptoe’, thus removing the body of the spider as far as possible from the dise’s surface, On further heating, Neogea sp. progressively orientates its body and then gradually postures, starting with the abdomen. It rotates the tip of the abdomen towards the incident radiation and this minimises the projected surface area of the ab- domen exposed to the sun. As the posturing develops the prosoma also is aligned with the abdomen so that the entire spider is orentated prosoma from the sun with minimal silhouette area exposed. Eventually the Jegs themselves are rot- ated forwards until they are parallel to the long axis of the spider in which position they are in the shadow of the abdomen, as is the prosoma; this is the full Fabian Position from which the spider tracks the sun (Humphreys, 1991, 1992). By these means the spiders potentially can obtain very fine contro] of their silhouette area and hence on their temperature, InN. edulis many behaviours were recognisable as similar to those observed in other spiders (e.g. orientation, posturing. agitation: Humphreys, 1991, 1992), whereas others have not previously been reported or recognised (e.g. drooping). Some behaviours recognised may be components of the same behavioural sequence. For example, Agita- hon, in which the spider circles around the hub, involves the body being raised slightly from the 548 web, a behaviour sometimes seen on its own. Both behaviours are included here under the same category. Thermally there appears little difference between three categories recognised here as dif- ferent behaviours (agitation and body lift, front legs raised, and start to posture). Work conducted under more controlled conditions in the laboratory may separate thermally these behaviours or allow their pooling using more rigorous criteria. Eleven behavioural categories are recognised in N. edulis, ranging from Repose to web abandonment which occur between Tp of 33.9 and 44.8°C (Table 2). The spider temperature associated with many of these behaviours is significantly different from others. Some of these behaviours reduce the projected body surface area exposed to the sun and thus, under the predictions of the physical model, should result in lower equilibrium body tempera- ture, all else being equal (e.g. orientation, postur- ing, leg raising, leg rotation and web abandonment). Other behaviours may not be ther- moregulatory but are associated with the onset of the next behaviour in the graded series (e.g. agita- tion and body lift) or facilitate a subsequent stage (e.g. silk laying to enable correct leg placement for full posturing). As in Neogea sp. (Humphreys, 1992), some be- haviours themselves form a graded series which should proffer gradually increased ther- moregulatory effects. Both front leg raising and front leg rotation occur initially in the front legs followed by the second pair of legs. In addition contralateral legs are not necessarily lifted or rotated at the same time. DISCUSSION Two classes of observation refute the hypothesis that posturing serves an anti-predator role as stated in the introduction. Firstly, if the Fabian position reduce the sil- houette area against the brightest part of the sky as an anti-predator defense (i.e. to make them less visible) then they should posture to the sun under clear conditions irrespective of the intensity of the sunlight; they do not. Furthermore, under conditions of patchy heavy clouds (cumulus and cumulo-status) against a clear sky, the spiders should assume a Fabian position with respect to the brightest sector of the sky; they do not. Secondly, many thermally related behaviours are themselves graded so that they are exhibited progressively as the spider warms. This provides the strongest evidence for the thermoregulation hypothesis because partial stilting, posturing or MEMOIRS OF THE QUEENSLAND MUSEUM Behaviour Mean Repose - see Table 1_|— oe Part orientation 33.9 0.57 6 33.1-34.7 [Drooping (36.5 (157 (8 | 35.4-38.8 Orientation {38.7a pa | 34.2-403 Agitation and body lift |38.7a 2.09 21 35.2-43.5 Front legs raised 38.9a 2.84 ll 35.0-43.3 Start to posture 40.4b 2.16 27 34,.8-43.6 6 |39.3-42.6 Rotate front legs 42.4ced 0,99 10 41.2-44.3 Abandon web 44,8d 0.50 3 44.3-45.3 TABLE 2. Mean temperature (Tp °C) of N. edulis on Rottnest Island, Western Australia, associated with different behaviours (ANOVA - Fs 8.93 = 15.233, P<0.001). Common letters include means not differ- ing significantly (Fisher’s PLSD at a= 0.05). orientation (Humphreys, 1992) makes no sense under alternative hypotheses but is entirely con- sistent with, and predicted from, the ther- moregulation hypothesis. The body temperature of a spider is a complex function of many intrinsic factors (size, morphol- ogy, attitude, physiology, reflectance, etc. ) as well as factors extrinsic to the individual (e.g. wind speed, turbulence, air temperature, incident radiation and its spectral characteristics; Mon- teith and Unsworth, 1990). It is because Tp is a complex function of intrinsic and extrinsic fac- tors that makes Ta a poor predictor of thermal behaviour. Hence, the observation that a spider may not always assume the Fabian position (or other presumptive thermoregulatory behaviour) at the same T, does not imply that the behaviour has no thermoregulatory significance. For ex- ample, Lycosa godeffroyi Koch in Canberra began basking at much lower T, in winter (4°C) than in summer (17°C) and reached 35°C onclear winter days at Ta of 11°C (Humphreys, 1974, 1978); the latter shows the dominant role of boundary layer effects for such surface dwelling spiders. Although orb-weaving spiders are often high above the ground, such boundary layers may assume more importance in those orb weaving spiders that incorporate a surface in their web (e.g. Neogea sp. and leaf curling species; Humphreys, 1992). These many classes of observation support the hypothesis that the posturing and/or reorientation that spiders undergo in intense sunlight is of thermoregulatory significance. Many are not alone adequate to support unequivocally the ther- moregulation hypothesis (e.g. Table 3: 4, 6, 9), some, in combination with others, support the Condition at spider THERMAL BEHAVIOUR IN SPIDERS Behavioural response and thermal consequences 1° Cool weather in shade 2* Cool weather in sun Manipulation Nil Repose; T,=T; Repose; Th>T, 3° Cool weather in sun Nil =S Repo se Tp>Ta 549 TABLE 3. Summary of characteristics of ther- moregulatory behaviour in orb-weaving spiders. Definitions: Spiders as- 4 Cool weather in sun Orientate and/or posture; T,>T, >S 5* Hot weather in shade Nil 6 Hot weather in shade T° Hot weather in sun Nil [Repose:Ti=Ts Onrientate and/or postureX tracks sun; sume Fabian position in hot but not in cold weather. denotes sunlight redirected onto the spider at about intensity of natural minimise Ty sunlight using a plane mir- 8 Hot weather in sun < than natural intensity using ° . Repose; in extremis may suffer heat death a concave mirror (>S or < 10 Very hot day in shade | Nil without postr S). The spider is simul- LI Very hot day insun | Nil Seeks shade taneously artificially 12 Population in hot sun | Varied web orientation minimise T), 13 Population in hot sun Large & small spiders All spiders orientate in same direction; Large spiders posture earlier in day than small shaded (s) or not (S). Num- bers with * are considered alone, and numbers fol- 14 Hot weather in sun =S perpendicular to sun 15* Grade n-1 behaviour |>S Spider postures mid-way between two incident heat sources Grade n behaviour; behavioural cascade culminating in Fabian lowed by common Ietters are considered together, to support strongly the ther- moregulation hypothesis. 16 Hot weather in sun =S below horizontal 17 Cool weather in shade | =s Apparent confusion in some species;> Tp Posture to > exposure to heat source; T}>Ta hypothesis (e.g. 1-7), while others support no other hypothesis (e.g. 15). While the emphasis here has been on behay- iours that reduce the heat load, spiders should use behaviours to warm them in order to enhance the time they are at optimal temperatures. This is the case in burrow dwelling lycosids (Humphreys, 1974, 1978, 1987a, 1987b) as well as in orb web spiders which may seasonally orientate their webs to maximise the projected surface area to warm more or faster (Carrell, 1978; Tolbert, 1979). While there is an indication of size related effects in thermoregulatory behaviour in Nephila spp., as may be expected theoretically using a simple physical model, no such size effect was observed in Stegodyphus lineatus Latreille (Henschel et al., 1992). While the thermal behaviour of spiders is much more sophisticated than has been accepted, the presumed advantages of such fine tuning are not understood. None the less, the recognition of such behaviour is an important aspect of field studies and the means to do so are required, especially for smaller spiders which are intractable subjects for direct recording of temperature in the field. How- ever, the sensible use of this schema should allow easy appraisal of the overt body positions of spiders in the field as to their likely thermoreg- ulatory significance and it should assist in disen- tangling thermoregulatory from other be- haviours. A thermoregulator with the battery of finely graded behaviours seen here should, under ideal conditions, be able to maintain a near constant body temperature under a wide range of environ- mental conditions. In practice their temperatures fluctuate markedly with every air movement, at least partly owing to their small thermal capacity. If the spiders are innately incapable, owing to their small mass, of precise thermoregulation, why have they developed such a wide range of sophisticated behaviours which should permit precise thermoregulation? ACKNOWLEDGEMENTS It is a pleasure to acknowledge the occasional assistance of Rae Young in the field and the Young family for allowing me to work on their property ‘Mandalay’. I thank Mark Elgar and Yael Lubin for their many constructive com- ments. Some of this work was undertaken during the tenure of a Christensen Research Institute Fellowship and with the approval of the Madang Provincial Council; the advice and assistance of Matthew Jebb and his staff is greatly appreciated. The work was funded by the Australian Research Grants Scheme (#D181/15274) and the Austral- ian Research Council (#A18831977 and #A 18932024), LITERATURE CITED ALEXANDER, A.J. & EWER, D.W. 1958. Tempera- ture adaptive behaviour in the scorpion, Opis- thopkthalmus latimanus Koch, Journal of Experimental Biology 35: 349-359. BIERE, J.M. & UETZ, G.W. 1981. Web onentation in the spider Micrathena gracilis (Arancae: Araneidae), Ecology 62: 336-344, CARREL, LE. 1978. Behavioural thermoregulation during winter in an orb-weaving spider. Sym- posium of the Zoological Socicty of London 42: 4-50. CRAIG, C.L. & BERNARD, G, D, 1990, Insect atirac- tion to ultraviolet-reflecting spider webs and web decorations. Ecology 71; 616-623. EBERHARD, W.G, 1973. Stabilimenta on the webs of Uloborus diversus (Araneae: Ulobordae) and other spiders. Journal of Zoology, London 171- 367-384. EDMUNDS, J. & EDMUNDS, M. 1986. The defensive mechamsmms of orb weavers (Araneae: Araneidac) in Ghana, West Atrica. Pp. 73-89. In Eberhard, W.G., Lubin, Y.D. and Robinson, B.C. (Eds), Proceedings of the Ninth international Congress of Arachnology, Panama, 1983. (Smithsonian In- stitution Press: Washington, D.C.). EWER, R.F. 1972. The devices in the web of the West Alffican spider Argiope flavipalpis. Journal of Natural History 6; 159-167. FOELIX, R.F, 1982, Biology of Spiders, (Harvard University Press: Cambridge, Massachusetts). HEATWOLE, H. 1970. Thermal ecology of the Desert Dragon Amphibolures inermis. Ecological Monographs 40; 425-457. HENSCHEL, J.R., WARD, D, & LUBIN, Y. 1992. The importance of thermal factors for nest-site selec- fon, web construction and behaviour of Stego- dyphies lineatus (Araneac: Bresidac) in the Negev Desert. Journal of thermal Biology 17: 97-106. HUMPHREYS, W.F. 1974. Behavioural thermoregula- tion in a wolf spider. Nature, London 251: 302- 503. 1978. The thermal biology of Geolycosa godeffrayi and other burrow inhabiting Lycosidae (Araneac) in Australia. Oecologia, Berlin 31: 319-347. 1986. Heat shunting in spiders. Pp. 41-46. In Can- gresso Intermacionale Arachnologia, vol. |. (Ed. J.A. Barrientos), Jaca, Spain. 1987a, The thermal biology of the wolf spider Lycosa tarentula (Araneae: Lycosidae) in north- em Greece. Bulletin of the British Arachnologi- cal Society 7: 117-122. 1987b, Behavioural temperature regulation, Pp. 56- 65, In, Nentwig, W (ed). ‘Ecophysialogy of Spiders’. (Springer-Verlag: Berlin.) 1991. Thermal behaviour of » small spider (Araneae: Araneidae: Arancinae) on spinifex in MEMOIRS OF THE QUEENSLAND MUSEUM Westem Australia. Behavioural Ecology and Sociobiology 28: 47-54. 1992, Stabilimenta as parasols: shade constnaction by Neogea sp. (Araneae: Araneidae, Argiopinae) and its thermal behaviour, Bulletin of the British Arachnological Society 9: 47-52 LUBIN, Y.D. 1986. Web building and prey capbare in Uloboridae. Pp. 132-171, In Shear, W,A, (Ed). Spiders: webs, behavior, and evolution. (Stanford University Press: Stanford, California). LUBIN, Y.D. & HENSCHEL, J.R. 1990. Foraging at the thermal limit: burrowing spider (Seorhyra, Eresidae) in the Namib Desert dunes. Oecologia 84: 461-467, MARSON, J. 1947. Some observations on the ecologi- cal variation and development of the cruciate zig- zag camouflage device of Argiope pulchella (Thor,), Proceedings of the Zoological Society of London 117; 219-227, MONTEITH, J.L. & UNSWORTH, M.H. 1990. Prin- ciples of environmental physics, (Edward Amold; Landon), OLIVE, C.W, 1980. Foraging specializations in orb- weaving spiders, Ecology 61: 1133-1144. RIECHERT, S.E. & TRACY, CR. 1975, Thermal balance and prey availability : Bases for a model relating web-site characteristics to spider reproductive success. Ecology 56: 265-284, ROBINSON, M.H. & ROBINSON, B. 1973, The stabilimenta of Nephila clavipes and the origin of stabilimentum-building in Araneids. Psyche 80: 277-288. 1974, Adaptive complexity: the thermoregulatory postures of the golden-web spider Nephila clavipey at low ajtitudes. American Midland Naturalist 92; 386-396, 1978. Thermoregulation in orb-weaving spiders: new descriptions of thermoregulatory postures and experiments on the effects. of coloration. Zoological Journal of the Linnean Society, Lon- don 64: 87-102. SUTER, R.B. 1981. Behavioural thermoregulation: solar orientation in Frontinella communis {Linyphiidae), a 6-mg spider. Behavioural Ecol- ogy and Sociobiology 8: 77-81. TOLBERT, W.W. 1979. Thermal stress of the orb- weaving spider Argiepe trifasciata (Araneae). Oikos 32: 386-392. WARD, D. & HENSCHEL, J.R. 1992. Experimental evidence thal a desert parasitoid keeps its host cool. Ethology 92:135-142. WILLMER, P. 1991. Thermal biology and mate ac- quisition in ectotherms. Trends in Ecology and Evolution 6; 396-399. WILLMER, P.G, & UNWIN, DM. 1981. Field analyses of insect heat budgets: reflectance, size and heating rates, Oecologia 50; 250-255, HYPERTROPHY OF MALE GENITALIA IN SOUTH AMERICAN AND AUSTRALIAN TRIAENONYCHIDAE (ARACHNIDA: OPILIONES: LANIATORES) GLENN S. HUNT AND EMILIO A. MAURY Hunt, G.S. and Maury, B.A. 1993 11 11: Hypertrophy of male genitalia in South American and Australian Triaenonychidae (Arachnida: Opiliones: Laniatores). Memoirs of the Queerisland Museum 33(2); 551-556. Brisbane. ISSN 0079-8835. Hypertrophy of male genitalic elements, particularly the stylus, is described and discussed. A stylus is regarded as hypertrophied if stylus length is sub-equal to or longer than trancus length. Greatest hypertrophy occurs in the Australian specics Cluniella distincta Forster (stylus x4.5 trunens) and a new genus, new species from South America (%2.5 truncus). Other species discussed are Aracanobunus juberthiei Muiioz-Cuevas from South America, and . minvta Forster, Rhynchobunus arragans Hickman, Tasmanobunas parvus Hickman, Tasmanonuncia sp., Allobunus distinctus Hickman and Thelbunus mirabilis Hickman from Australia. To accommodate an clongate stylus, the truncus is often shortened, and the genital operculum and sternum modified so that the genital orifice is located more anteriad. Hypertrophy of the stylus may be associated with the hypertrophy or reduction of other terminal elements. [n Clunie/la spp, and the two South American species penetration of the stylus occurs along a very Jong yagina; the spermathecae are situated at the base of the ovipositor. Hypertrophy may have evolved as aconsequence of sexual selection, (|Opiliones, Triaenonychidae, male genitalia, hypertrophy, morphology, sexual selection. Glenn S, Hunt, Divisionef Invertebrate Zoplogy, Australian Museum, P.O, Box A285, Sydney South, New South Wales, 2000, Australia; Emilio A. Maury, Museo Argentino de Ciencias Naturales ‘Bernardine Rivadavia’, Casilla de Correo 220 Sucursal 5, 1405 Buenos Aires, Argentina; 3 November, 1992. The triacnonychid penis comprises a basal trun- cus supporting an apical complex which includes the stylus and associated plates, processes and setae. In the primitive condition, three sets of plates are present (Fig. 1.4): the dorsolateral plates which are embryologically derived from the trun- cus and the dorsal plate and ventral plate embryologicaily related to the stylus (Martens, 1986). Both the dorsal and ventral plates were apparently primitively paired but are now fused, at least basally. The ventral plate carries setae, Certain taxa have undergone loss or reduction of plates (Martens, 1986; Hunt and Hickman, 1993). A few taxa have undergone extreme hypertrophy in the length of the stylus with one or more of the associated plates frequently showing correlated hypertrophy, or reduction, depending on the taxon. HYPERTROPHIED STRUCTURES CLUNIELLA SPP. The most extreme hypertrophy of the stylus known for the family occurs in Clunielladistincra Forster, 1955 of SE Queensland and NE New South Wales (Fig. 2A). The stylus is x4.5 truncus length. There is correlated morphological change in the female where spermathecae occur basally in the ovipositor (Fig. 5c), unlike the usual con- dition where the spermathecae occur sub-apical- ly. Therefore, the long stylus probably penetrates almost the whole length of the ovipositor to reach the spermathecae. The dorsolateral plates of the penis are elongate, gradually tapering to x2 ventral plate length (Fig. 2B). The dorsal plate is either lacking or intimately fused with the stylus: the latter is suggested by the subterminal lateral processes on the stylus which may be homologous to terminations of the dorsal plate (see Thelbunus mirabilis below, Fig. 5A). The ventral plate is reduced in size, and the number of infenor setae ts reduced from three to two pairs. The extreme stylus is accommodated within the body by shortening of the truncus, and by clon- gation of the genital operculum and posterior invagination of the sternum which together shift the genital opening anteriad. The sternum mar- gins tend to follow the genital operculum (Fig. SE: ef. female genitostermal region, Fig. SF) but when the operculum is lifted the shape resembles that in Fig, 5H. Cluniella minuta Forster, 1955, which overlaps in distribution with C. distincta, has undergone less radical elongation of the stylus (Figs 2c-D). Nevertheless, the stylus is x1.4 truncus length- The spermathecae are also basal despite the 552 Ss. Ab fied | | (- ~ fis y" | N | a5 i nee eats fc ap - l/ ‘ t ‘ | l figm-ve via # bey? \ 4- 28 n ~ ) ' ad ( on \ ~ | | { } | | | | ; f | | ; ij | | i A | \" ry 4 | ave 1 4 } | } fl { Di}! A ‘ore j Vii a La /\\ ali] : is a | ‘|| Vy) yf | | } | | | \F i) . oe | , } \ " j {vi & \| y\ ' ‘| \ he, | yi ' ae A At we i P—\ Wot | FIG. 4. Hypertrophied ¢ genitalia in Tasmanian Tri- aenonychidae, A, B: Raynchobunus arrogans , \ateral and ventral. C, D: Tasmanobunus parvus , lateral and ventral, E, F: Tasmanonuncia n.sp. (Hunt, in prep.), lateral and ventral. G, H: Allobunus distinctys, lateral and ventral. seem initially accommodated by shortening of the truncus (C. minuta condition). Changes to the genital operculum and sternum evolved later. Cluniella spp. and the two South American species described above show close cotrespon- dence in many features associated with stylus hypertrophy: great elongation of stylus, modification of sternum and genital operculum, shortening of truncus, and spermathecae situated basally in the ovipositor at the end of a very long vagina. The question is whether these features indicate aclose phylogenetic relationship or whether they are examples of convergence. The latter is sup- ported because: 1. Modifications to genitostermal architecture appear to have arisen independently within the Cluniella lineage, evolving from the ‘normal’ condition as occurs in C. minuta. 2, Attachment of penis sheaths is basal in Cluniella and mesial in South American species. 3. The penes of the South American species HYPERTROPHY OF MALE GENITALIA oD | | =p __ A If 1) a te if .: dio. ; f FIG, 5, Hypertrophy of genitalia in Thelbunus mirabilis and modified structures associated with genitalic hypertrophy in various Triaenonychidae. A, B: T. mirabilis, lateral and detail of lateral showing hypertrophy and modification of ventral plate setae. C,D: Ovipositor in Cluniella distincta and Araucanobunus juberthiei respectively showing basal seminal receptacles, E, F: Genitosternal region of C. distincta, d and 2 respectively. G, I: Genitostemal region of South American new genus, new species (Maury,inprep.), d and % respectively; H = shape of sternum in ¢ after genital operculum removed. J, K; genitosternal region of T: mirabilis, 3 and 2 respectively: go = genital operculum; sp = spermatheca; st=sternum; v = vagina (not delineated in C. distincta). show closer affinity with the South American genus Triaenonychoides (see Maury, 1987)) rather than with Australian genera. 4. Apart from the basal spermathecae and long vagina, the ovipositor of the South Amencan species appears to be of the typical triaenonychid form. The ovipositor of both Clumiella spp. is highly derived in having a very membranous tip, in lacking well developed sensory lobes, and in catrying vestigial setae. In some specimens ex- amined the membranous tip was inflated and had *ballooned’ out the genital orifice. This morphol- ogy suggests that the female may assist penetra- 555 tion by inflating the ovipositor so that it partly engulfs the stylus. Thus, assuming that the male C. minuta has not undergone a reversal in genitosternal architecture, the derived ovipositor seems to have evolved before shortening of the male sternum and elongation of the genital oper- culum. Thus, the genomes of Cluniella and the two South Ametican taxa have the capacity to allow quite remarkable convergence in a syndrome of characters. The overall! effect appears the same, but the details differ. Why have such vastly elongate styluses evolved, particularly to the extreme shown by C. distincta? Sexual selection by female choice is. favoured by Eberhard (1985) as the most general- ly applicable explanation for ‘extravagant’ genitalia. Eberhard proposes that ‘male genitalia function as ‘internal courtship’, devices to in- crease the likelihood that females will actually use a given male’s sperm to fertilize her eggs rather than those of another male’. In the case of Cluniella and the South American species, it is postulated that males with the largest styluses have greater success than males with smaller styluses and hence contribute more of their genes. to the next generation, The genitalia may stimu- late the female prior to or during copulation and so activate the appropriate responses, or it might provide the right mechanical and sensory ‘fit’ during copulation, The basal spermathecae in the ovipositor of Cluniella spp. and the two South American species (and the long stylus matching the long spermathecae in Ballarra spp.) suggest that the correct mechanical fit may at least be part of the answer. A search for congeners and an analysis of inter- and intraspecific variation, as well as behavioural studies, may yield further data to resolve these questions. ACKNOWLEDGEMENTS The first author was assisted by an Australian Biological Resources Study grant. Drs Michael Gray (Australian Museum) and A. Roig-Alsina (Museo Argentino de Ciencias Naturales), and Mr James Cokendolpher (Lubbock, Texas), com- mented on the manuscript. Mr Roger Springthorpe did the illustrations. and Ms Sue Lindsay the SEMs. LITERATURE CITED EBERHARD, W.G, 1985. “Sexual Selection and 556 Tag ce Berens a ae MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 6, Genitosternal region in Thelbunus spp. and variation in sternum; A = sp. nov.; B = T. mirabilis. Genital operculum lifted; note recess in sternum where folded stylus fits. Scale bars= 500m. Animal Genitalia’. (Harvard University Press: Cambridge, Mass). 244pp. HUNT, G.S. 1985. Taxonomy and distribution of Equi- tius in eastern Australia (Opiliones: Laniatores: Triaenonychidae). Records of the Australian Museum 36; 107-125. HUNT, G.S. & COKENDOLPHER, J.C. 1991. Ballar- rinae, a new subfamily of harvestmen from the Southern Hemisphere (Arachnida, Opiliones, Neopilionidae). Records of the Australian Museum 43: 131-169. HUNT, G.S. & HICKMAN, J.L. 1993. A revision of the genus Lomanella Pocock and its implications for family level classification in the Travunioidea (Arachnida: Opiliones: Triaenonychidae). Records of the Australian Museum 45;81-119. MARTENS, J. 1986. Die Grossgliederung der Opiliones und die Evolution der Ordnung (Arach- nida). Actas X Congreso Internacional de Arac- nologia, Jaca, Espana 1: 289-310, MAURY, E.A. 1987. Triaenonychidae Sudamericanos. IV, El genero Triaenonychoides H. Soares 1968 (Opiliones, Laniatores). Boletin de la Sociedad de Biologia de Concepcién, Chile 58: 95-106. MUNOZ-CUEVAS, A. 1973. Descripcion de Araucanobunus juberthiei gen. et sp. nov. de Tri- aenobunini de Chile (Arachnida, Opiliones, Tri- aenonychidae). Physis, Buenos Aires, Secc. C 32(84): 173-179. PREDATOR-PREY CO-EVOLUTION OF PORTIA FIMBRIATA AND EURFYATTUS SP_, TUMPING SPIDERS FROM QUEENSLAND ROBERT R. JACKSON anv R. STIMSON WILCOX Jackson, R.R, and Wilcox, R.S, 1993 11 11: Predator-prey co-evolution of Portia fimbriata and Euryaitus sp., jumping spiders from Queensland. Memwirs af the Queensland Museum 33(2): 557-560. Brisbane. ISSN 0079-8835, Portieis a salticid that preys on other spiders and Euryaitus sp, is 2 salticid that nests inside suspended rolled-up leaves. Portia and Euryattus are sympatric at a site near Cairns but not known to be sympatric at other sites studied. Portia from the Cairns site practices a unique prey-specific predatory behaviour against Exryartus, and Euryartus From this site is efficient at detecting and defending itself against Portia. Euryattus, but not Portia, 1s present at a site near Davies Creek which, although only ca 15km from the Cairns site, is more xeric and at a higher elevation. Three types of tests were carried out to compare Fortia’s efficiency at catching adult allopatric versus sympatric Euryatrus (Test 1), allopatric Eurvartus juveniles versus juveniles of another salticid species on which Portia is known to prey (Test 2) and allopatric versus sympatric Euryattus juveniles (Test 3). In these tests, Portia behaved similarly toward allopatric (Davies Creck) and sympatric (Cairns) Euryatius, except that it attacked and killed allopatric more often than sympatric Euryattus. Allopatric Euryattus, in contrast to Cairns Evrvaitus, appeared not to recognize an approaching Portia as a predator.]Portia fimbriata, Euryattus, Jacksonoides, co-evolution, allopatry, sympatry, Robert R. Jackson, Department of Zoology, University of Canterbury, Christchurch 1, New Zealand; R. Stimson Wilcox, Department of Biological Sciences, Slate University of New York at Binghamton, Binghamton, New York 13902-6000, U.S.A.; 30 November, 1993. Portiaisa genus of specialized jumping spiders (Salticidae) that prey on other spiders (Jackson and Hallas, 1986). Portia is a detritus mimic and has a unique, slow, choppy style of locomotion that seems to preserve its crypsis. There are seven described species of Portia, distributed in the tropics of Africa, Asia, and Australasia (Wanless, 1978). A population of Pertia fimbriata (Doles- chal!) in Queensland uses specialized behaviour to catch other species of salticids (Jackson and Blest, 1982). This population of P. fimbriata also uses a prey-specific predatory behaviour against females of a particular sympatric salticid, Euryat- tus sp. (Jackson and Wilcox, 1990). Euryattus females suspend a dead, rolled-up leaf by strong guylines from rock ledges and tree trunks, then use the leaf as a nest (Jackson, 19845). Portia has never been observed to atlempi to catch Euryattus by going inside the rolled-up leaf. However, in Queensland, P. fimbriata uses vibratory displays to lure Euryattus females from their nests (Jackson and Wilcox, 1990). These displays apparently mimic courtship displays of Euryattus males (Wilcox and Jackson, unpubl. data). Other species of Portia and populations of P. fimbriata m areas from which Euryattus is absent do not perform these displays (Jackson and Wilcox, 1990). Queensland P, fimbriata will wait for hours at atime for Euryattus to come out of its nest (Jack- son and Wilcox, 1990). Often, Ewryattus actively defends itself by leaping at Portia and driving it away UJackson and Wilcox. 1990). This is un- usual behaviour for a salucid. From thousands of observations of interactions between P. fimbriata and many different species of salticids (Jackson and Hallas, 1986), it is evident that Euryarnus is more efficient than other salticids at recognizing and defending itself against an approaching Por- tia. Also, in laboratory tests (Jackson and Wilcox, 1990), Euryattus readily recognized an approach- ing Portia as a potential predator, whereas Jack- sonoides queenslandica, another salticid on which P. fimbriate feeds (Jackson and Blest, 1982), did not recognize P. fimbriata. This sug- gests an evolutionary ‘arms race’ (sensu Dawkins and Krebs, 1979) between Euryattus and P. Jinthriaia. Frequent predation by P.fimbriate on Euryattus may have favoured special abilities in Euryattus to recognize and defend itself against P. fimbriata, This, in turn, may have resulted in the evolution of refinements of P. fimbriata’s predatory behaviour. To test this hypothesis. we must compare the behaviour of Euryativs in populations with and without Portia. Recently, such an opportunity arase when Euryaltus were found in an area in which Portia was not known. 558 MATERIALS AND METHODS Cages, maintenance, terminology, basic testing procedures and analysis are given in Jackson and Wilcox (1990). Laboratory cultures of sympatne Euryatius, J, queenslandica and P. fimbriata were established, using spiders collected from rainforest near Caims at about sea level (see Jackson, 1985; Jackson and Hallas, 1986). A laboratory culture of allopatric Eunwthes was established from spiders collected in an Acacia- Eucalyptus woodland beside Davies Creek, near Davies Creek Nattonal Park in the Atherton Tableland (about 15km from the study site near Caims andatc. 500m elevation). Portia has never been recorded from this and other Atherion ‘Tableland habitats (Wanless, 1978; Jackson, un- publ. data). Unless noted otherwise, all spiders tested were reared in the Laboratory from eggs of freld-collected spiders. No individual spiders were used in more than one test. In this paper, we refer to Euryattus from Caims and Davies Creek us “sympatric Euryattus’ and ‘allopatric Euryattus’, respectively. There were no evident differences related to general behaviour between these two populations of Euryartus. In particular, similar leaves were suspended by females for nests and males courted with similar vibratory displays. The systematics of the genus Euryanus remains uncertain. Whether the two populations of Euryatrus we studied are one or two different species is not now known. Voucher specimens were deposited at the Florida Collection of Arthropods (Gainesville) and the Queensland Muascum. We conducted three tests. In Tesi 1, Portia was given access to an adult allopatric Euryarus female in her nest. In Test 2, on alternate days, Portia was given access to a juvenile (2-3mm in hody length) allopatric Euryatius and a juvenile (23mm) J. queenslandica in a bare cage (1.e..n0 nest or other objects present). In Test 3, on alter- nate days, Portia had access to a juvenile (2- 3mm) of an allopatric and a juvenile of a sympatne Evryattus ina bare cage. To begin each type of test, Pertia was placed into a cage con- taming the other spider shortly after lights came on in the laboratory (0800 hours). Spiders were observed continuously until predation occurred or until 4h fad elapsed. Each test was either wWentical or at least similar to tests carried out previously Jackson and Wilcox, 1990). Data from Test 1 using allopatric Euryatius adults were compared to data from the identical MEMOIRS OF THE QUEENSLAND MUSEUM type of tests using sympatne Euryartus adults in an earlier study (Jackson and Wilcox, 1990) to see whether Portia’s capture efficiency against allopatric Euryattus adults was greater than against sympatric Euryattus adults. Test 2 using allopatric Ewryartus juveniles was compared to type 2 tests in Jackson and Wilcox (1990) using sympatne Euryattus juveniles and J. queenslan- dica juveniles. We already know that Portia cap- tures J. queenslandica juveniles more efficiently than it captures sympatric Euryattus juveniles (Jackson and Wilcox, 1990). Here we examine whether Portia’s capture efficiencies against these two salticids vary when Epryattis is al- lopatne. Test 3 enabled us ta compare Portia’s efficiency at captunng allopatnc and sympatric Euryattus juveniles. Adult body length is c.8mm for both J. queenslandica and P. fimbriata and for both populations of Exryattus. Jackson and Wilcox (1990) used three size classes, defined by the ratio of prey to predator body volume, when testing P. fimbriata with juvenile salticids: smal] (0.1- 0.25), medium (0.S-J), and large (1.5-2). Only two of these (medinm and large) were used here. MeNeinar tests for significance of changes were used for statistical analyses of the results from Tests 2 and 3, these tests being designed as paired comparisons (Sokal and Rohlf, 1981): each individual Portia was used in one test with one salticid and another test with the other salticid 48 h earlier or later (decided randomly). Yates’ corrections were applied to the McNemar tests, and the Bonferroni adjustment (see Rice, 1989) was made to significance levels whenever single data sets were used in multple comparisons. RESULTS Test |: Buevarryes Apu 1s Nest P. fimbriata behaved sunilarly toward al- lopatric (herein) and sympatric (Jackson and Wil- cox, 1990) Euryartus, except that it attacked and killed allopatric Euryattus more frequently than sympairic Euryattus (Fig. |, test of independence, P<0.01). Allopatric Euryattus appeared less prone than sympatric Euryattus to recognize P. fimbriata as a predator: 85% of the P. fimbriata got onto the leaf with allopatric Euryatius, but only 43% got onto the leaf with sympatric Euryar- tus, 23% of sympatric Euryartis, but only 4% of allopatric Euryatius, drove P. fimbriata away (Fig. 1). PREDATOR-PREY COEVOLUTION Altopatric Guryattue N= 32 SO Sympatric Eut yale N=30 100 Percentage of Tests E drove P away E-dtove P off P moved slowly attache and P never got close = guyline or onte leat Oregiine FIG. 1. P. fimbriata (P) tested with adult allopatric (Davies Creek) and sympatric (Crystal Cascades) Euryattus females (E) in suspended, rolled-up leaves. Data for sympatric Euryattus from Jackson and Wil- cox (1990). Close: on leaf or guyline connected to leaf, or dropping on dragline toward leaf. For each outcome of test, number given above bar and percent- age is read from axis. Test 2: JUVENILE EURYATTUS AND JACKSONOIDES QUEENSLANDICA There was no evidence that Portia captured or stalked J. gueenslandica more frequently than allopatric Euryattus (Figs 2, 3, McNemar tests, NS). Allopatric Euryattus did not appear to recognize Portia asa predator any more readily than did J. queenslandica. Test 3; CamRNS AND Davies Creek EuryATTUS JOVENILES There was no evidence that Portia stalked sym- patric Euryattus any more frequently than al- lopatric Euryatius, but Portia caught allopatric 80 30 ge of Tests Percent Popursued =P pursued 0 piursum) PF caplifed P captuietl P captured J only E only J and E J only E only {ana £ FIG, 2. Responses of P. fimbriata (P) to medium size (see text) allopatric Euryartfus (E) and sympatric J. queenslandica (J). 40 paired tests: each Portia tested with one Euryattus and, on an alternate day, with one Jacksonoides (sec text). Data for ‘P pursued neither J nor EH’ and ‘P captured neither J nor E’ not displayed. 559 10 40 3 a 30 & - 29 a 5 % 20 8 S 15 © 40 Lo 3 P pursue =P oun F pursued =P Fapturedd P captured ? captures J only and & ony E only Jand © FIG. 3. Responses of P, fimbriata (P) tested with large (see Lext) allopatric Euryattus (E) and sympatric J. queenslandica (J), 25 paired tests: each Portia tested with one Euryatfus and, on an allernate day, with one Jacksonoides (see text). Data for ‘P pursued neither J nor E’ and ‘P captured neither J nor E’ not displayed. Euryattus more often that it caught sympatric Euryattus (Figs 4, 5). DISCUSSION Only one population of Portia fimbriata from Caims studied (Jackson and Wilcox, 1990) is sympatric with Euryattus. Euryattus suspends a rolled-up leaf for a nest, and this is the only salticid sympatric with the Cairns Portia, or with any other Portia studied, known to do this. Only the Cairns Portia is known to use a prey-specific predatory behaviour against Euryattus. The sym- patric (Jackson and Wilcox, 1990), but not the allopatric , Euryaitus appears readily to recognize and defend itself against Portia. In fact, the al- 100 80 60 40 Petcentage of Tests 20 B poe P purdved PF pursued P eed P eaplued Pp _Fanturnd only only Sand A S oni A only FIG. 4. Responses of P. fimbriata (P) to medium size (see text) sympatric (S) and allopatric (A) Buryatrus sp. juveniles. 38 paired tests: each Portia tested with one sympatric and, on an alternate day, with one allopatric Euryatius (see text), Data for ‘P pursued neither S nor A’ and ‘P captured neither § nor A’ not displayed. Percentage of Tesis Popumued =P purgued = pwevet FF Captured F caplued F captured S only 4 only Sana S ony A only Sand A FIG. 5. Responses of P. fimbriata (P) to large (see text) sympatric (S) and allopatric (A) Euryatrus sp. juveniles. 28 paired tests: each Portia tested with one sympatric and, on an alternate day, with one allopatric Euryattus (see text), Data for *P pursued neither S nor A’ and ‘P captured neither § nor A’ not displayed. lopatric Euryattus appears to be no better than J. queenslandica at escaping predation by Portia , whereas Portia captured J. queenslandica more efficiently than it captured the sympatric Euryat- ius (Jackson and Wilcox, 1990). The ability of the Cairns Euryattus appears to be a predator- specific antipredator behaviour. Population differences were evident despite there being no known prior experience of the predator by the prey or the prey by the predator under laboratory rearing conditions in this and the earlier (Jackson and Wilcox, 1990) study, These findings suggest that, in the Cairns area, Portia and Euryattus appear to have acted as selective agents on the evolution of each other’s behaviour. ACKNOWLEDGEMENTS We thank Curt Lively, Mark Elgar and Marianne Willey for useful discussion and criti- MEMOIRS OF THE QUEENSLAND MUSEUM cal reading of the manuscript. Financial support was provided by grants from the National Geographic Society (3226-85) and the U.S.-New Zealand. Cooperative Program of the National Science Foundation (NSF Grant BNS 8617078). LITERATURE CITED DAWKINS, R. & KREBS, J.R. 1979. Arms races be- tween and within species. Proceedings of the Royal Society, London B 205: 489-511. JACKSON, R.R. 1985. The biology of Euryattus sp. indct., a web-building jumping spider (Araneae, Salticidae) from Queensland: utilization of silk, predatory behaviour and intraspecific interac- tions. Journal of Zoology, London (B) 1: 145-173. JACKSON, R.R, & BLEST, A.D. 1982. The biology of Portia fimbriata, a web-building jumping spider (Araneae, Sallicidae) from Queensland: uwtiliza- tion of webs and predatory versatility. Journal of Zoology, London 196; 255-293. JACKSON, R.R. & HALLAS, S.E.A. 1986. Compara- tive biology of Portia africana, P. albimana, P. Jimbriata, P. labiata, and P. schultzi, araneo- phagic, web-building jumping spiders (Araneae, Salticidae): utilisation of webs, predatory ver- satility, and intraspecific interactions, New Zealand Journal of Zoology 13: 423-489. JACKSON, R.R. & WILCOX, R.S. 1990. Aggressive mimicry, prey-specific predatory behaviour and predator-recognition in the predator-prey interac- tions of Portia fimbriata and Euryattus sp., jump- ing spiders from Queensland. Behavioral Ecology and Sociobiology 26: 111-119. RICE, W.R. 1989. Analyzing tables of statistical tests, Evolution 43: 223-225. SOKAL, R.R. & ROHLF, F.J. 1981. ‘Biometry’. (Freeman: San Francisco), WANLESS, R.F. 1978. A revision of the spider genus Portia (Araneae: Salticidae), Bulletin of the British Museum (Natural History) Zoology 34: 83-124. “WE’LL MEET AGAIN”, AN EXPRESSION REMARKABLY APPLICABLE TO THE HISTORICAL BIOGEOGRAPHY OF AUSTRALIAN ZODARITDAE (ARANEAE) R, JOCQUE Jocqué, R. 1993 11 11: “We'll meet again”, an expression remarkably applicable to the historical biogeography of Australian Zodariidae (Araneae). Memoirs of the Queensland Museum 33: 561-564. Brisbane. ISSN 0079-8835. The largest subfamily of the Zodariidae, the Zodariinae, contains 31 genera and has endemic representatives on all tropical continents. The sequence in this clade first indicates that the Austrahan zodariid fauna is the result of a combination of vicariance and dispersal events. Only three zodariid genera are not endemic to Australia. It is argued that two of these. Mallinella and Asceua, have reached Australia by dispersal over forest-covered areas. It is remarkable that the endemic Australian genera in the Zodariinae are more closely related to the African ones than are the Neotropical genera which is in contrast with the current ideas on chronology in plate tectonics. A possible explanation might be found in the past and present distribution of forests, The appearance of this type of vegetation on the Crelaceous- Tertiary boundary, might also be invoked to explain bipolar distnbutions in Africa. La plus importante des sous-familles des Zodarlidae, les Zodariinae. contient 41 genres, dont des endémiques sur chaque continent tropical, La séquence dans ce grand clade indique d'abord que la composition de la faune australienne serait le résultat d'une combinaison de vicariance et de dispersion, Seuls trois genres trouvés en Australie n’y sont pas endémiques. On avance l’argument selon Jequel deux d’entre enx ont réussi a alleindre |’ Australie par dispersion a travers des aires couvertes de foréts, [| est remarquable que les genres endémiques australiens soicnt plus proches des genres africains que de ceuxd’ Amérique du Sud ce qui contredit les idées courantes concernant la chronologie de la dérive des plaques. Une explication possible pourrait se trouver dans la distribution passée et actuelle des foréts équatoriales. La génése de ce type de végétation, a la fin du Crétacé, pourrait également expliquer la distribution bipolaire de certaines vieilles lignées Winvertébrés. DAfrica, Gondwanaland, distribution, vicariance, Rady Jocqué, Koninklijk Museum voor Midden-Afrika, B-3080 Tervuren, Belgium; 13 October, 1992. The Zodariidae are a medium-size pantropical family of mainly nocturnal, ground-living spiders. Except for the members of the subfamily Storenomorphinae they are yirtually all bur- rowers to some degree, Some simply dive into sand (Psammoduon) or hide in litter (Asceua, Mallinella) whereas others make a complex retreat consisting of a burrow with a trapdoor (Psammorygma, Neostorena) or an igloo-like construction of pebbles or grains of sand (Diores, Zodarion), This sedentary lifestyle and the fact that zodariids do not balloon explains why most species have small distribution ranges, It also makes them an ideal subject for zoogeographical Studies, moreover since a cladistic analysis of the family is available (Jocqué, 1991), THE AUSTRALIAN ZODARIIDAE Most Australian zodariids, estimated at several hundred species, belong to genera endemic to the Australian continent. There is no trace of any Distribution. Palacotropics & Australia Australia southern Gondwana circamforest steppe -woodland Habronestes [shania __|Sowth and Central America |ecincurnforest____| Neostorena _| Australia [steppe -woodland —_| Storena steppe -circumnfores TABLE I. Distribution and habitat of some zodariid gencra, Asceua Asterou Cyrioctea representatives of these genera on any other con- tinent (Table 1). Three genera have representatives elsewhere and in fact have the centre of their distribution outside Australia. The first one is Cyrioctea, the only genus in the Cyriocteninae, found exclusive- in sandy habitats such as arid dunes and sand eserts. It has a typical Gondwanan distribution 502 FIG, 1. Approximate distribution of Mallinella. with representatives in South Africa, Chile and Australia (Cyrioctea raveni Platnick and Griffin). Both the other genera, Mallineila and Ascena, have an enormous distribution which appears to be linked with old world forests. One species of each has ceached the northern tp of Australia. The Australian zodariid fauna 1s thus apparent- ly composed of three different stocks: a strictly endemic one, a southern Gondwanan one and a third element that could be quoted as old world forest fauna. To understand this composition we have to go back to an era before the breakup of Gondwanaland. The Zodariidae indeed have q basic Gondwanan distribution with the more plesiomorphic taxa represented in Africa, Australia and South America. These are the Cyrioeleinae, the Lachesaninae and the more plesiomorphic members of the Zodariinae, The latter taxon is now known to include what has been described as the subfamily Storeninae (Jocqué, 1991, 1992). Thirty-one out of 47 genera now belong in the Zodariinae. However, the more apomorphic members of the subfamily (Femoral Gland Clade or FOC), having seVeral synapomor- phies (femoral gland, lack of chilum, flattened incised hairs, fused chelicerae) are present only in Africa (including part of the Palaearctic) and tropical Asia, The same applies to the Storenomorphinae and the Cydrelinae which are resincted to tropical Africa and tropical Asia. When Africa got finally separated from other major landmasses, slightly more than 100 mybp, these three groups were apparently nol yel in existence. The bulk of the zodariid fauna outside that continent is therefore suppased to be derived of the plesiomorphic taxa present at the time of the split-off. However, from the above tt fs clear that India (and part of South East Asia *) carried i much more modern assemblage of Zodariidae when it moved towards its present position. In- deed, there is no evidence that at least purely MEMOIRS OF THE QUEENSLAND MUSEUM tropical forest organisms (c¢.g., Mallinella) originating in Africa, have been able to reach India via a northern itinerary. No forest connec- tion has ever existed via the mediterrancan and the Arabian peninsula. This paradox ts discussed below. Virtually all Zodariidac are restricted to habitats lying in a climatic zone with a marked dry season. In the Neotropics only a few species (in Jshania and Tenedos) seem to have adapted ta moist forest and no zodariids have so far been found in Amazonia. In Australia no true forest- inhabiting species belonging to endemic genera appear to be present, although some species in the genera Neastarena, 6) trapped at burned and unburned (control) sites, at Lac Ekomiak, Québec. n= total number of individuals trapped, bath sites combined; 7BS= percentage individuals caught at burned site. = Pardosa uintana, P. mackenziana and P. xerampelina; — = adults of H. herniosa and juvenile Hila/ra specimens. RESULTS MESIC SITE A total of 772 spiders was collected from 6 study sites (3 burned, 3 unburned!) in northem Québec during July-August. 1990, Individuals of two families, Linyphiidae and Lycosidac, clearly dominated all collections; individuals of Gnaphosidae ranked third among trap captures {Table 1), Both at Lac Ekomiak and at Kuujjuarapik, trap captures were higher at burned sites than at un- burned sites. This was mainly due to the great numbers of Lycosidae caught at open burned sites. The figures for the two most abundant families were (Lac Ekomiak and Kuujjuarapik combined): Lycosidae 208 at burned and 76 at unburned sites, Linyphiidae 188 and 229 respec- tively, In general, at the burned sites, the diversity (H) was higher or equal compared to the un- burned controls (Table 1), Altogether 56 species were caught, 37 species were trapped at Lac Ekomiak and 34 at Kuuj- juarapik. Namber of species from bumed sites was 47; from unburmed sites 37; 28 species were common te both bumed and unburned sites. Linyphiidae (Erigoninac and Linyphiinac), Lycosidae, and Gnaphosidae were numerically dominant in species number, with 3] (24 and 7), 9 and 6 respectively. Species that actively colonized the burned sites included, among the lycosids, Pardosa hyper- STT [Pardasa hyperborea 16 (100.0 [only at burned site _| [Pocadicnemisamericana [6 [100.0 [only at bumed site _| Arctose alpigena to burned site [Pardovauintano (100 [74.0 |t0 bred sit [Graphosa muscorum [10 __|70.0_| stightly to burned site | Sisisrorundus a eo [Sisicotrus montanus [22 (59.1 lequallyoccurring _| aetna — he fist hosts | lo control site | Hilaira hermiasa 66 1136 Leptlyphantes complicaras | 19 5.3 TABLE 3. Common spiders (> 6) trapped at bumed and unbumed (control) sites. at Kuujjuarapik, Québec. n = total no. of individuals trapped, both sites com- bined; % BS =percentage individuals caught at burned site; * = adults of H. herniova and juvenile Hilaira specimens. borea (Vhorell) in both study areas and Alopecesa aculearta (Clerck) at Lac Ekomiak (Tables 2, 3). The species group of Pardosa uintana Gertsch, P. mackenziana (Keyserling) and P. xerampelina (Keyserling), including many juveniles, as well as Arctosa alpigena (Doleschal) at Kuujjuaraptk, and Trochosq terricola Thorell at Lac Ekomiak, also were more abundant at bummed than unbumed Siles. The gnaphosids caught, Gnaphosa microps Holm and G. museorwm (L.Koch), were slightly more abundant at burned than unburned sites. OF the linyphiids (Engoninae), Diplocentria biden- tara (Emerton) and Pecadicnemis americana Millidge apparently “preferred’ burnt areas (Tables 2, 3). Many species were represented by less than 4 individuals captured, and consequently not in- cluded in the Tables 2. 3, Several were found only at burved sites. This group mcluded: Gnaphosa parvula Banks, Zelotes fratris Chamberlin, Par- dosa furcifera (Thorell), Neon nelli Peckham and Peckham, Sisieus apertus (Holm), Ceraticelus atriceps(O.P_-Cambridge), Horcoles quadricris- rafus (Emerton). Setastes truncatus (Emerton), Tunegyna debilis (Banks), Walckenaeria atrotibialisO.P_-Cambridge, W. castanea (Emet- ton), W. directa (O.P.-Cambridge) and W. tricor- nis (Emerton). Several species seemed to Jack habitat specificity and were equally found in marked numbers at both burned and unburned sites. Such species included the linyphiids, Sists ronendus S78 (Emerton), Sisicottus montanus (Emerton) and Agyneta olivacea (Emerton); and the thomisid Ozyptila gertschi Kurata. These generalist species must be regarded as colonizer species because of their common occurrence at burned sites, Although only in a few cases (Pardosa hyperborea and P. uintana) “preferences” to bummed areas were statistically significant, about 30 of the 47 species caught at bumed sites can be regarded as potential colonizers in the subarctic postfire forests investigated. Species that clearly avoided burned sites were the linyphiids Leprthyphantes complicatus (Emer- ton), L. alpinus (Emerton), Hilaira hermniosa (Thorell), Latithorax ebtusus (Emerton), and Agyneta allosubtilis Loksa. OF the lycosids, Par- dosa moesta Banks was found only at the un- burned mesic forest at Lac Ekomiak. DISCUSSION The bummed areas at Lac Ekomiak and at Kuuj- juarapik greatly differed both in the intensity of fire and in the size of area bummed. At Kuuj- juarapik, spiders easily colonized the burned site from surrounding nearby natural areas. By con- trast, at Lac Ekomiak, species colonizing the burned sites came from long distances (Le., several hundred metres), especially at the dry bumed site, The possible survival of spiders in the bumtarea during the fire is open to discussion (cf. McKay, 1979: 246); however, at the dry bummed site its seems to be improbable due tc the intensity of the fire, The spider community trapped at burned sites one year after fire was nch; the diversity (H) was not lower than at unbumed sites. Similar results were found in subarctic Finland during the first postfire summer (Koponen, 1988). This contrasts with some earlier studies (Schaefer, 1980; Metz and Dindal, 1980). However, also Schaefer (1980) observed high diversity values already two years after fire in pine forests of Germany. Some of the species that colonized burned sites in northern Québec are considered pioneer species in other northern areas, e.g- Diplocentria bidentata in bumed areas of northem Finland (Koponen, 1988), MEMOIRS OF THE QUEENSLAND MUSEUM ACKNOWLEDGEMENTS I thank Louise Filion and the staff of Centre d'études nordiques for working facilities and generous help at Kuujjuarapik and Québec City. Luc Sirois provided help at Lac Ekomiak. and Heli Hunme participated in the field work. LITERATURE CITED BECKWITH, R.C. & WERNER, R.A. 1979. Effects of fire on arthropod distribution. Pp. 53-55. In Viereck, L.A. and Dyrness, C.T. (eds) ‘Ecological effects of the Wickersham Dome fire near Fair- banks, Alaska’. (USDA, Forest Service, General Techn. Rep., PNW-90). BUFFINGTON, J.D, 1967. Soil arthropod populations of the New Jersey Pine Barrens as affected by fire. Annals of the Entomological Society of America 60: 530-535, HAUGE, E. & KVAMME, T. 1983. Spiders from forest-fire areas in southeast Norway. Fauna Nor- yegica, Ser, B, 30: 39-45, HUHTA, Y. 1971, Succession in the spider com- munities of the forest floor after clear-cutting and prescribed burning. Annales Zoologici Fennici 8: 483-542. KOPONEN, S. 1988. Effect of fire on spider fauna in subarctic birch forest, northem Finland. Technis- che Universitat Berlin, Dokumentation Kongresse und Tagungen 38: 148-153, 1989, Effect of fire on ground layer invertebrate fauna in birch forest in the Kevo Strict Nature Reserve, Finnish Lapland. Folia Forestalia 736: 75-80. MCKAY, RJ. 1979. The wolf spiders of Australia (Araneae: Lycosidae): 12, Descriptions of some Western Australian species, Memoirs of the Queensland Museum 19: 341-275. METZ. LJ, & DINDAL, D.L. 1980. Effects of fire on soil fauna in North America. Pp. 450-459. In Dindal, D.L, (ed.) ‘Soil Biology in Related to Land Use Practices’. Proceedings of the 7th Intemation- al Colloquium of Soil Zoology, Syracuse. PAYETTE, S., MORNEAU, C., SIROIS, L. & DESPONTS, M. 1989. Recent fire history of the northern Québec biomes. Ecology 70: 656-673. PEARSE, A.S. 1943, Effects of burning-over and raking-off litter on certain soil animals in Duke Forest. American Midland Naturalist 29: 406-424. SCHAEFER, M, 1980, Effects of an extensive fire on the faunaof spiders and harvestmen (Araneida and Opilionida) in pine forests. Proceedings of the 8th even Congress of Arachnology, Vienna: )03-108. DIVERGENT TRANSFORMATION OF CHELICERAE AND ORIGINAL ARRANGEMENT OF EYES IN SPIDERS (ARACHNIDA, ARANEAE) OTTO KRAUS AND MARGARETE KRAUS Kraus, O. and Kraus, M. 1993 11 11: Divergent transformation of chelicerae and original arrangement of eyes in spiders (Arachnida, Araneae). Memoirs of the Queensland Museum 33(2): 579-584. Brisbane. ISSN 0079-8835. In various higher taxa of the Araneae (e.g., Mesothelae, Migidae, Hypochilidae), the chelicerae and their fangs show an intermediate position between those commonly called orthognathy and labidognathy. This stage is considered to form part of the ground pattern of spiders; accordingly, it is called plagiognathy (new term). It is concluded that plagiognathy gave rise to orthognathy and labidognathy as divergent adaptational developments. In most instances, plagiognathy is correlated with the maintenance of the original (plesiomorphous) arrangement of the lateral eyes (= ALE + PLE + PME) in triads or semi-triads. The previous assumption that orthognathy and the arrangement of eight eyes in two subparallel rows are characters that were already present in ancestral spiders is refuted. Bei verschiedenen héheren Taxa der Araneae (z.B. Mesothelae, Migidae, Hypochilidae) weisen die Cheliceren sowie deren Klauen eine intermediare Position zwischen Orthognathie und Labidognathie im tiblichen Sinne auf. Diese Anordnung wird als Teil des Grundmusters der Echten Spinnen angesehen und hierfiir die neue Bezeichnung Plagiognathie eingefiihrt. Von diesem primaren plagiognathen Zustand werden sowohl die Orthognathie als auch die Labidognathie als divergente Entwicklungen mit unterschiedlichem Anpassungswert ab- geleitet. In den meisten Fallen ist Plagiognathie korreliert mit dem Erhalt der urspriinglichen (plesiomorphen) Anordnung der Seitenaugen (VSA + HSA + HMA) in Form von Triaden oder Semi-Triaden. Die bisherige Annahme ist nicht Janger aufrecht zu erhalten, wonach Orthognathie und die Anordnung von 8 Augen in zwei Querreihen als Komponenten des Grundmusters der Spinnen angesehen worden waren. [jAraneae, plagiognathy, orthog- nathy, labidognathy, lateral eyes, triads. Otto Kraus, Margarete Kraus, Abteilung fiir Phylogenetische Systematik, Zoologisches Institut und Zoologisches Museum, Universitét Hamburg, Martin-Luther-King-Platz 3, D-2000 Hamburg 13, Germany; 12 November, 1992. It is generally believed that the chelicerae in spiders can be arranged in either of two different ways, described by the terms orthognathy and labidognathy. Orthognathy is commonly thought to represent the primitive (plesiomorphic) char- acter stage (Foelix, 1982: 3; Platnick and Gertsch, 1976: 13). At first glance, this view seems to be supported by the fact that a strictly orthognathous arrangement of these mouthparts is also present in the outgroup of the Araneae, i.e., in the Amblypygi. Hence, the idea that orthognathy is a plesiomorphic feature seems to be the most par- simonious explanation. Accordingly, labidog- nathy is regarded as a derived (apomorphic) feature. Kaestner (e.g., 1952, 1953a, b) presented arguments supporting the assumption that labidognathous, i.e., cooperating chelicerae had various functional advantages. He produced a model (Fig. 1) illustrating the transformation of a ‘primitive’ orthognathous arrangement into the labidognathous position. However, it is difficult to imagine how this could have happened gradually, and Kaestner did not explain why or- thognathy had been maintained in a considerable number of higher taxa. Simon (1892: 64, 82) pointed out that the Liphistiidae and Migidae had arrangements of the chelicerae that did not fit very well into the generally accepted orthognathy/labidognathy scheme. Later authors ignored such ‘deviations’, however, and continued to base the distinction of two major subtaxa of spiders-Mygalomorphae (=Orthognatha) and Araneomorphae (=Labido- gnatha) on different positions of the chelicerae. Kaestner alone remarked on the intermediate ar- rangement of these mouthparts in Actinopodidae and in Hypochilus, but apparently he too con- tinued to adhere to the typological ortho- gnathy/labidognathy concept. One main aspect of his study was therefore to classify the chelicerae in Hypochilus as orthognathous or labido- gnathous. In this paper, we will present relevant facts, most of them already known for decades, and discuss conclusions allowed by alternative con- cepts. sau FIG, 1, Transformation of chelicerae as supposed by Kaestner. A, orthognathy, left chelicera omitted, front of prosoma nearly vertical, B, labidognathy, dotted lines and arrows indicate how front of prosoma (with chelicerae) shifted from original vertical to a horizon- tal position (rotation of basal segments of chelicerac not indicated). C, suggested economy of relatively small cooperating labidognathous chelicerae com- pared with a single orthognathous chelicera (hatched); both seize objects of same size. (From Kaestner, 1953b). This approach leads directly into a critical discussion of another generally accepted dogma in arachnology—that the eight eyes present in the ground pattern in spiders were originally ar- ranged in two more or less parallel rows. In the nearest outgroups (Amblypygi, Uropygi), how- ever, the arrangement of these eight eyes is quite different: the lateral eyes form triads on both sides of the prosoma, Such triads also occur ia certain spiders, We therefore also plan to adopt a some- what unconventional approach, discussing the question as to Whether the presence of such triads in various subtaxa of the Araneae could be a persisting plesiomorphic character expression. RESULTS AND INTERPRETATIONS (CHELICERAE FACTS, Orthognathy is commonly regarded as plesiomorphic. However, precisely those spiders that have the greatest number of plesiomorphies in common (Platnick and Gertsch, 1976) do not show an orthognathous position of their chelicerae: in the Liphistiidae (Figs 2a-b) the basal segment (paturon) of these mouthparts is relatively short, inflated and obliquely posi- tioned, Further, the longer axis of this basal seg- ment is orientated obliquely downwards, and not horizontally and paraxially as in ‘tre’ Orthog- natha (Figs 2c-d). The corresponding position of the fangs is also oblique. and anything but paraxial, in contrast to the position of the fangs in Atypus, for example (see Simon, 1892: 64). The same situation as in Liphistiusis also found in various subtaxa of the Mygalomerphae. In 1892, Simon {(: 82) described similar arrange- MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 2. Position of chelicerae and fangs, lateral and ventral views. A-B, Mesothelae: Liphistius sp. C-D, Atypidae: Avypus affinis. E, Migidae: Migas quintus, F, Actinopodidae: Missulena cccatoria, G, Hypochilidac: Hypochilas gertschi. H, H. thorelli.— (A-B from Millot, 1949; C-D, F, H from Kacstner, 1952; E from Wilton, 1968). ments in the Migidae, referring to ‘chélicéres trés courtes, convexes A la base, mais ensuite brusque- ment inclinées, presque verticalement ..,” (see Fig, 22). Kaestner (1952: 118) studied Sason robustum (OQ, P.-Cambridge, 1883) as a repre- sentative of the Barychelidae and characterized the chelicerae as short and subvertically inclined. In the same paper, Kaestner demonstrated that obliquely arranged chelicerae were also present in the Actinopodidae (Fig. 2f); he described the situation in Missulena occatoria (Walckenaer, 1805) and concluded: ‘I cannot see any biological teason for such conditions, But as torsions of this kind play an important role in the origin of labidognathy, it is interesting to see that they [the torsions] may also occur in the Orthognatha’ (trans). from German). Itis worth mentioning that the chelicerae even of the oldest known spider, Atterocopus fimbriun- guis (Shear, Selden and Rolfe, 1987) (Middle Devonian), had short basal segments and also fangs (Selden ef al., 1991, e.g., plate 1, figs 6-8). TRANSFORMATION OF SPIDER CHELICERAE (i) OW Fe FIG, 3. Orthognathy (left) and labidognathy (right) as apomorphic character states derived fram plagiog- nathy (bottom). Unfortunately, their original position is un- known, Chelicerac with an oblique position are also found in a taxon that unquestionably belongs to the Arantomorphae (= Labidognatha awct.): the Hypochilidae (Figs 2g-h). Again, 1t was Kaestner (1952: 132) who studied details. He concluded that the mouthparts in Hypochilus were of the orthognathous type in construction and expressed the view (Kaestner, 1952; 114) that ‘the majority of important characters present in Hypaochilus is jn accordance with the Orthognatha, whereas the number of features present in Labidognatha only is very low. For this reason, I must remove the genus from the suborder Labidognatha and either place it in the Orthognatha or set it up in a suborder of its own’ (transl. from German). INTERPRETATION Kaestner maintained that labidognathy was an advanced character stale, which had developed {rom an orthognathous ground pattern by gradual transformation (Kaestner, 1953a: 60; Fig. 1). He felt that Aypochilus (and the Hypochilidae) should be regarded as transitory stages and ex- plained the oblique position also present in the Barychelidae and Actinopodidae as a parallel development. Furthermore, he regarded the *semi-orthognathous’ chelicerae in Dysdera (Dysderidae) as intermediate. Kaestner thought, then, that various transitory stages still existed. forming a ‘phylogenetic link’ between the two extreme character states. We reject this judgement based on typology. and postulate that an oblique position of the chelicerae, including the fangs, really represents the plesiomorphic situation (Fig. 3). As a new term is needed, we would like to suggest *plagiognathy’ to designate this original position 581 of the chelicerae. Accordingly, the plagio- gnathous position presentin the ground pattern of the Araneae has been secondarily transformed in two different directions, both apomorphic char- acter states: orthognathy and labidognathy (Fig. 3), We see various arguments in support of this hypothesis: a) Tt explains why orthognathy is not en- countered in the Mesothelae (Liphistius, Hep- tathela). b) The absence of orthognathy in repre- sentalives of several mygalomorph families is explained. ¢) The fact that the Hypochilidae are not labidognathous is explained by the simple as- sumption that the original plagiognathy has been maintained in this group of the Araneomorphae, Nonetheless, in all other Araneomorphae (this means in the Neocribellatae, the sister taxon to the Hypochilidae) labidognathy has been achicev- ed and is regarded as an apomorphy of this taxon. This conclusion is not invalidated by the fact that superficially orthognathous arrangements ong- inated secondarily in a few sexually dimorphic araneomorph taxa (e.g., in males of the salticid genus Myrmarachine}. d) Kaestner’s typological and entirely theareti- cal model suggesting how a supposed transition from orthognathy to labidognathy could come about (Fig. 1) is replaced by a new concept (Fig. 3). This postulates divergent and gradual evalu- tionary change of the ground pattern, that is to say, of plagiognathy. e) Kaestner’s complicated assumption that obliquely arranged chelicerae originated im para- Nel both in the Mygalomorphae and the Araneo- morphae is replaced by a simple, comprehensive hypothesis. The only remaining conflict seems to be that reflected in the strictly orthognathous position of the chelicerae in the most closely related out- groups of the Araneae (Amblypygi, Uropygi). If our ‘plagiognathy hypothesis’ is correct, it must be assumed that orthognathy in the Araneae is a different and thus independent secondary development within the mygalomorph spiders. There is no question but that this contradiction needs some further examination. Preliminary investigations have already sug- gested that orthognathy in Amblypygi may be different from orthognathy in spiders; the basal segment in amblypygid chelicerae has a long, stout apodeme at its proximal dorsolateral border, which reaches deeply into the broad, flat prosoma. This peculiarity is lacking in plagio- 362 gnathous and also in orthognathous chelicerae of spiders. We expect that more detailed studies on the functional morphology, including the mus- culature, will demonstrate that orthognathy in uropygids and amblypygids differs from ortho- gnathy in spiders. This would support our view and could perhaps constitute point f) in the list of positive arguments above. Eves Surprisingly. plagiognathous spiders (for ex- ample Mesothelae, Migidae, Hypochilidac) share a special arrangement of the eyes (Figs 4g, e, c): anterior lateral, posterior lateral and posterior median eyes are grouped closely together. This prompts the following remarks on the question as to how the eyes were grouped in the ground pattern of the Araneae. As designations widely used in taxonomic descriptions (AME, ALE, PME, PLE) disregard the origin of these ‘ocelli°, some notes on the homolgy of the eyes of spiders may be ap- propriate to ensure that we understand each other. the anterior median eyes (AME) will be called “median eyes’ by us, as they are homologous with the median eyes of other arthropods (for example those in Xiphosura, ‘ocelli’ in insects, and the three components of crustacean nauplius eyes). All other eyes, three on each side, will be called ‘latetal eyes’ (ALE + PLE + PME), as they are homologous with the paired onginal compound eyes in arthropods, for example. in xiphosurans, FACTS {tis commonly believed that an arrangement in (wo transverse rows of eight eyes is plesiomor- phic. Only two weak aspects support this view. however: (i) there 1s no reason at all] to dewbt that the presence of eight eyes forms part of the araneid ground pattern, and (b) their arrangement in two rows is widely observed both in the Mygalomorphae (for example the Actinopod- idae; see Simon, 1892: 79, figs 81-83) and in the Araneomorpha (for example Araneidae, Euspar- assidae, Thomisidae). On the other hand, lateral eyes more or less distinctly grouped in triads occur in various groups of spiders. Mesothelae, Migidae and Hypochilidae have already been mentioned. Al- most perfect triads occur in Pholcidae (Fig. 41), The same is true of Amblypygi (Fig. 4b) and Uropygi, the direct outgroups to spiders! The arrangement of the eyes. in the extinct Trigonotarbida deserves special attention, Ac- cording to Selden etal. (1991; 254), they form the sister group of all other pulmonate taxa (= MEMOIRS OF THE QUEENSLAND MUSEUM fs, £74 #0) T ( "hel, | \ ern " “ es = 8 @ , us { a b iy oS Cc “ & es “y = "\ “Oe: : C.J t ay Moa Y ie ay th 7 E Hi ! FIG. 4. Position of median (black) and lateral eyes in Trigonotarbida, Amblypygi und Araneae. A, Trigonotarbida: Gilboaruchne eriersoni, reconstruc- tion of prosoma (from Shear ef al., 1987). - B, Amblypygi: Damon sp, C, Hypochilidae: Hypochilus gerteciu, D, Atypidac: Anypus affinis. E, Migidae: Poecilomigas sp. F, Pholcidae: Pholeus circularis. G, Mesothelac: Liphistius sp. H, Dysderidge: Dysdera sp. 1, Agelenidae: Agelena sp. (Not to scale), Araneae + Amblypygi + Uropygi + Schizomida). Devonian trigonotarbids had the usual two median eyes, and the lateral eyes were repre- sented by up to 9 (12 ?) lenses (Fig. 4a). Three of these were major lenses, while the others were minor lenses arranged in the interspace between the major ones (Shear et al.. 1987), This kind of transformation of the original compound eyes clearly indicates that a triad of major lateral eyes is a feature of the ground pattern of the pul- monates as a whole; accordingly, the loss of the minor lateral eyes could be regarded as an aut- apomorphy of all other pulmonates. including spiders. This secondary reduction of the minor lateral eyes may explain why most triads are not perfectly closed, not even in amblypygids (Fig. 4b). The peculiarity ‘lateral eyes in triads’ is com- monly used as a character in spider identification keys, but as faras we can tell, ils potential bearing on phylogeny has never been discussed, Could it be that triads of lateral eyes are part of the ground pattern m the Araneae? A survey of how the lateral eyes are positioned in representatives of higher taxa of spiders shows that almost perfectly *closed* triads (as in phol- cids) are rare. In most instances, the three lateral eyes on each side are somewhat dissociated. In addition to the Mesothelae and Migidae already mentioned, we should also like to draw attention TRANSFORMATION OF SPIDER CHELICERAE to the Atypidae (Fig. 4d) and to the illustrations in Raven’s comprehensive study of the Mygalo- morphae (1985). In many cases the posterior lat- eral and the posterior median eyes are closely connected, with some distance between them and the anterior laterals. Hypochilus shows slightly dissociated triads (Fig. 4c). The Dysderidae (Fig. 4e) and Oonopidae are six-eyed spiders, having the median eyes completely reduced. In dys- derids, the lateral eyes are closely grouped together, resembling the arrangement of the laterals in the Mesothelae. In many groups within the Araneomorphae, diads are present instead of triads. They are formed by the ALE + PLE, with the PME separated. This arrangement can be found in Austrochilidae and especially in most Theridiidae and Linyphiidae, for example. Diads also occur in groups characterized by a secondary loss of the PME, such as Scytodidae. INTERPRETATION The assumption that eight eyes arranged in two transverse rows were already present in the ground pattern of the Araneae is not supported by any concrete fact; nor would this at all correspond with the situation in the nearest outgroups. It would mean that triads and triad-like arrange- ments of the lateral eyes in spiders were classifi- able as parallel developments (homoplasies). This is unlikely. In accordance with the position of the eyes in the Amblypygi and Uropygi, we expect that the laterals were primarily grouped as triads (ALE + PLE + PME). This hypothesis is supported by five arguments: a) Triads of major lateral eyes (lenses) already existed in Devonian Trigonotarbida; hence, triads apparently form part of the ground pattern of all pulmonates among arachnids. b) The postulated configuration is in good agreement with the arrangement of the eyes in the direct outgroups. c) Triads and semi-triads present in various groups of the Mygalomorphae and also of the Araneomorphae must no longer be explained by assumed parallel origin. d) Various types of somewhat dissociated lat- eral eyes can be explained by a secondary separa- tion of the ALE or of the PME from the others, which frequently remain in contact with each other. e) Simon’s ‘oculi laterales utrinque contigui’ 583 (e.g., 1894: 517), that is to say, the occurrence of diads can be explained as part of the original triad. To some extent, the question remains open, as to how it is possible to distinguish between eye positions that can be regarded as more or less modified triads and other positions, with secon- darily approximated ALE and PLE. PERSPECTIVES Apparently, plagiognathy is part of the ground pattern of the Araneae. Developments in the directions of orthognathy and labidognathy can easily be explained as divergent evolutionary changes (Fig. 3). The question therefore arises of how these might be correlated with functional aspects. As an impetus for further discussion, we propose the following working hypotheses: a) In the Mygalomorphae, orthognathy may be correlated with the capture of prey on the ground. Under such conditions, the two parallel fangs of the chelicerae can easily penetrate the victim on a substrate like two stabs of a dagger. It seems remarkable that a semi-orthognathous position of the chelicerae has originated secondarily in the Dysderidae: they kill woodlice on the substrate. b) In the Araneomorphae, the origin of labido- gnathy may be correlated with the evolution of capture webs (sheet, frame, orb webs etc.). These could make it more efficient to bite the prey with two opposing chelicerae or fangs, whereas plagiognathous and, even more, orthognathous chelicerae might not penetrate but rather push away the victim: there is no longer any substrate ‘supporting’ prey animals. c) Plagiognathy and the maintenance of lateral triads or semi-triads of eyes apparently form part of the ground pattern of spiders; these features are confined to more ‘primitive’ groups. The presence and the various types of transformation of these two characters should be integrated into current concepts on the phylogeny of the Araneae (see, for example, Raven, 1985; Coddington, 1990). At present, our view of features of an araneid ground pattern and succeeding evolution- ary changes seems to be somewhat at odds with various published cladograms; they hence could be partially wrong. We feel that this conflict may be due to the possibility that characters assumed to be synapomorphies in various cladograms (see, 1 But see Kaestner (1953a: 62). He believed that the position of the chelicerae in Dysdera was a ‘phylogenetic link’ between orthognathy and labidognathy, Unfortunately, he was not aware that the first postembryonic stages were nearly labidognathous, with relatively shorter basal segments and only slightly oblique fangs (pers. observ.). In Dysdera, the final semi-orthognathous position was gradually acquired in later instars. 584 e.g., Platnick and Shadab, 1976, fig. 1; Raven, 1985, fig. 1) may well turn out to be symples- iomorphies; e.g., Raven's characters 35 (eyes spread widely across the prosoma; same as Plat- nick and Shadab’s character 1) and 36 (male pedipalps: conductor of bulb present; see Kraus, 1978, figs 12, 14-16). ACKNOWLEDGEMENTS We are indebted to Prof. Dr. H.M. Peters, Tiibingen, and Prof. Dr. H.W. Levi, Cambridge, Massachussets, for critical advice. We express our thanks to Dr, W.A. Shear, Hampden-Sydney, who draw our attention to the situation in the Trigonotarbida and in other fossil arachnids. Dr. R. Horak, Graz, kindly provided early post- embryonic stages of Dysdera. LITERATURE CITED CODDINGTON, J.A. 1990. Ontogeny and homology in the male palpus of orb-weaving spiders and their relatives, with comments on phylogeny (Araneoclada: Araneoidea, Deinopoidea). Smith- sonian Contributions to Zoology 496; }-52. FOELIX, R.F. 1982. ‘Biology of spiders’. (Harvard University Press: Cambridge and London). 306pp. KAESTNER, A. 1952. Die Mundwerkzeuge der Spin- nen, ihr Bau, ihre Funktion und ihre Bedeutung fiir das System. 1, Teil; Orthognatha; Palacocrib- ellata. Zoologische Jahrbiicher (Anatomie) 72(1): 101-146. 1953a, Die Mundwerkzeuge der Spinnen, ihr Bau, ihre Funktion und ihre Bedeutung fiir das System. 2. Teil: Herleitung und biologische Bedeutung MEMOIRS OF THE QUEENSLAND MUSEUM der Labidognathie. Zoologische Jahrbiicher (Anatomie) 73(1): 47-68. 1953b, Die Mundwerkzeuge der Spinnen, ihr Bau, ihre Funktion und ihre Bedeutung fiir das System. 3. Teil: Die Cheliceren der Labidognatha (Di- pneumones). Mitteilungen aus dem Zoologis- chen Museum in Berlin 29(1): 3-54. KRAUS, O, 1978. Liphistius and the evolution of spider genitalia. Symposia of the Zoological Society of London 42: 235-254, MILLOT, J. 1949. Ordre des Aranéides (Araneae). Pp. 589-743. In Grassé, P.P. (ed.), Traité de Zoologic. Anatomie, Systématique, Biologie. (Masson: Paris). PLATNICK, N,I. & GERTSCH, W.J. 1976. The subor- ders of spiders: A cladistic analysis. American Museum Novitates 2607: 1-15. PLATNICK, N.1. & SHADAB, M.U. 1976. A revision of the mygalomorph spider genus Neocteniza (Araneae, Actinopodidae). American Museum Novitates 2603: 1-19. RAVEN, R.J. 1985. The spider infraorder Mygalomor- phae (Araneae): cladistics and systematics. Bul- letin of the American Museum of Natural History 182(1): 1-180. SELDEN, P.A., SHEAR, W.A. & BONAMO, P.M. 199], A spider and other arachnids from the Devonian of New York, and reinterpretations of Devonian Araneae. Palaeontology 34(2): 241- 281. SHEAR, W.A., SELDEN, P.A., ROLFE, W.D.I., BONAMO, P.M. & GRIERSON, J.D. 1987, New terrestrial arachnids from the Devonian of Gilboa, New York (Arachnida, Trigonotarbida). Amer- ican Museum Novitates 2901; 1-74. SIMON, E. 1892-1895. ‘Histoire naturelle des Araignées. Vol. 1’. (Librairie encyclopédique de Roret; Paris). 1O84pp. WILTON, C.L. 1968. Migidae. In Forster, R.R. “The spiders of New Zealand, vol. II’. Olago Museum Bulletin 2: 73-126, POLYNESIAN THOMISIDAE - A MEETING OF OLD AND NEW WORLD GROUPS PEKKA T. LEHTINEN Lehtinen, P.T. 1993 1] 11; Polynesian Thomisidae - a meeting of old and new world groups. Memoirs of the Queensland Museum 33(2): 585-591. Brisbane. ISSN 0079-8835, The Polynesian thomisid fauna ts postulated as consisting of an Hawaiian-cast Polynesian New World group, living mainly in isolated populations in the mountains and of repre- sentatives of two western Jowland groups originating from Australia and Southeast Asia, The former group has apparently speciated into numerous endemic species, while the latter groups are represented by a single, widespread species and a rare Tongan species, respec- tively. The ranges of the eastern and western groups do not overlap. The species of New World origin have been described or previously attributed to Misurnena, Misumenops, or Synaema. Allsuch species are included here in Mecaphesa Simon, 1900 with the type species from Hawaii. Misumenops P.O. Pickard-Cambridge, 1900 has the type species from Eastern Brazil and has no close relatives in Polynesia or in the Old World. A widespread Old World group is also recognized here and tentatively included in Massuria which appear to be related to the New Guinean Loxeporetes. Diaea as currently recognized is polyphyletic and the species occurring in west Polynesia (Diaea praetexta (L. Koch, |865)) is postulated to belong lo a group requinng a new penenc delimitation and name. Hedana sublilis L. Koch, 1874, also of Asian origin is here regarded as having affinity with Tharrhalea, The poorly described thomisid species of the isolated, southernmost island group of Polynesia, Rapa Island has not been studied. Araneae, Thomisidae, Polynesia, biogeagraphy. Pekka T, Lehtinen, Zoological Museum, University of Turku, 20500 Turkw, Finland) L7 March, 1993. Many zoogeographical discussions, including spiders, are flawed because of poor taxonomy. The zoogeography of the Polynesian spider fauna has been discussed by Berland (1927, 1928, 1929, 1930, 1933, 1934a. b, c, 1935a, b. 1937, 1938a, b, 1942, 1947), but his discussions were based on unrevised taxa. His conclusions were often af- fected by misidentifications and unevenness of data available. Most spiders for these papers con- sisted af assorted samples made by non- specialists and many were synanthropic species found near villages. I have been working towards a zoogeographi- cal synthesis of the Polynesian spider fauna for ten years. Extensive personal field work in moun- tain tops, but also in the disturbed zone has been the most important method in the elimination af anthropochorous dispersal and distinctly synanthropic species from all speculations on the origin of the fauna of natural habitats, The taxonomic revision of all families present seems to be necessary for any valid zoogeographical conclusions. As the first step 1 have carried oul 4 ‘generic’ revision of Polynesian families which allows the placing of most Polynesian species groups of spiders into named or still unnamed groups of supraspecific taxa instead af zoogeographically useless con- cepts such as the ‘worldwide’ Misumenops, Theridion, Hahnia, or Leucauge, Some recent papers on Polynesian spiders have been publish- ed (e.g. Marples, 1955a, b, 1957, 1959, 1960, 1964; Berry and Beatty, 1987; Beatly and Berry, 1988: Beatty ef al, 1991). I have previously discussed some aspects of the spider zoogeog- raphy of the Pacific region (Lehtinen, 198f). Polynesian thomisids have also been described by Strand (1913). The evolution of Polynesian Thomisidae has resulted in the most striking example of local speciation of spiders in Polynesia. The Thomisidae discussed comprise only the sub- family Thomisinae in the sense of Suman (1970) and various other authors. The Philodromidae are not a sister group of Thomisidae, but rather of the Heteropodidae. The geological history of the Polynesian ar- chipelagoes js now well known (Wilson, 1963; Duncan and McDougall, 1974; Dalrymple et al., 1975). An ancient continent of Pacifica has been proposed (with differing placement and size) marginally affecting to the historical zoogeog- raphy of Polynesia (e.g. Nur and Ben-Avraham, 1977; Craw, 1983). Most geophysicists agree that the Polynesian islands are nol parts of ancient land masses broken by processes of the plate tectonics, but rather chains of current islands and 586 seamounts representing former islands (Dal- rymple et al., 1975). The origin of the Polynesian fauna therefore can be explained only by long distance dispersal from different directions (Gressitt and Yoshimoto, 1963) and partly by intrapolynesian Speciation processes within the island chains (cf. also Carson, 1984; Fosberg, 1991). The use of the basic principles of the vicariance biogeography (Nelson and Platnick, 1981) will be essential for explaining the origin of groups of biota with complex patterns in their recent ranges. Craw’s (1978) variant of panbiogeography, Jater named spanning-tree biogeography by Plainick and Nel- son (1988) is a useful method for comparisons of area including also permanently oceanic island groups and it can be recommended for the analysis of many other groups of spiders. When patterns of distribution are very simple and anthropochorous dispersal in historical time has nat theroughly obscured the original pattems (cf. Stoddart, 1968), conclusions can be made with Craw's method such as have actually Jong been used by zoogeographers (e.g. Gressitt, 1961) before the concept of “the most parsimonious area relationship’ was defined and named. In spite of the current taxonomic confusion of the Thomisidae on a global scale some generalisations on the zoogeography of the fami- ly are possible in the Pacific area. This paper presents the suggested relationships and zoogeography of the Thomisidae of Polynesia according to rich new material and results of my unpublished revisional work. TAXONOMIC REMARKS The nominate subfamily of Thomisidac should be called Thomisinae, although the name Misumenimie has been widely used, also, e.g. recently by Dippenaar-Schoeman (1983). Two groups of greenish or yellowish species wilhout abdominal modifications are easily recognizable, one with conspicuous modifications in the ocular urea (Thamisus-group), the other without such modifications (Misumtena-group). The limitation of thomisine groups has been vague, Simon (1895) originally listed Miswnena, Heriaeus, and Diaea in different tribes, while at the other ex- treme, the Misumena-group of Dippenaar- Schoeman (1983) includes not only Thorniisus, hut also Runcinia, No phylogeny of thomisine groups is known and detailed discussion is beyond the scope of this study. However. the Misumena-group has MEMOIRS OF THE QUBENSLAND MUSEUM apparently retained many plesiomorphic charac- ters Some groups with striking individual adap- tive modifications (e.g. Heriaens and Runcinia) may be closely related to this group. There are most probably many other endemic species of Thomisinae in the mountains of French Polynesia, but a revision is excluded here. The definition and delimitation of thomisine genera has been based traditionally on a few adaptive characters, including number, length, and type of setae on the carapace (Simon, 1895; Mello-Leitao, 1929; Schick, 1965; Tikader, 1980; Dondale and Redner, 1978; Levy 1985: Ono, 1988), but little attention has been paid to general pattems of the genital organs and type of sexual dimorphism. In contrast to conventions in the taxonomy of other spider groups, the naming of individual setae of the thomisid carapace has been used by some recent specialists (Schick, 1965; Dippenaar-Schoeman, 1983), This ter- minology ts widespread in acarine taxonomy. Sore genera have been very obscurely defined and therefore all catalogues list them as being very widespread and species rich, ¢.2. Miswmena, Misumenops, Digea, and Synaema. All these generic names appear in thomisids described or listed from Polynesia. Even a superficial com- parison of the descriptions or type material from many species of these genera (L. Koch, 1874: Kulezynski, 1911; Chrysanthus, 1964; Tikader. 1980) reveals tat they are typical “waste-basket’ Eroups, where most species arenotclosely related to the respective type species_ The phylogenetic classification of the west Polynesian ‘Diaea’ and the east Polynesian ‘Misumenops’ has been time-consuming, as all basic taxonomic work on Indo-Pacific and Neotropical Thomisidae was done before modern taxonomic principles and methods became estab- lished. Most structural characters used as generic criteria in Thomisidae seem to be minor conyer- gently evolved adaptations. The type species of all three large widespread genera in question, Misumenops, Diaea, and Misumena, are atypical or ‘peripheral’ species, not closely related to the Pacific species. Actually the placing of many tropical species jn these three genera have been repeatedly changed, depending mainly on em- phasis laid on single adaptive characters, e.g. type and pattern of setae on carapace, pattern of ber spines, eye patie, etc. The setation of the carapace ts variable in the Polynesian groups of Thomisidae. Nevertheless, in Mecaphesa, sympatnc species may be best identified by differences in length and density of POLY NESIAN THOMISIDAE 7 limits of Polynesia total range of Indo-Pacific "Diaes" (TTT) total range of Mecaphesa c range of "Diaea" praetexta O range of Mecaphesa in Pacific stands » range and origin of Polynesian "Tharrhal: " FIG, 1. Geographic ranges and source of Polynesian thomisid groups. the carapace setae. The shape of the carapace is variable in Mecaphesa, while the shape of the abdomen is variable in both “Diaea' and Mecaphesa, even within one population. The colour pattern is variable also, although the ‘usual’ colouration for most species provides a reasonable guide to identification, if large populations are available. POLYNESIAN THOMISIDS OF NEW WORLD ORIGIN Most east Polynesian thomisids have been long included in Misumenops F.O. Pickard- Cambridge, 1900 (Berland, 1933, 1934b, 1942; Suman, 1970), although Roewer (1954) trans- ferred all Hawaiian species to Misumenoides F.O, Pickard-Cambridge, 1900. Many Hawaiian and North American species of Misumenops sensu Schick (1965) were originally described in Misumena or Diaea, and Neotropical species also in Meiadiaea Mello-Leitao, 1929. The adaptive radiation of Hawaiian Thomisidae indicates that essential changes in the shape of the carapace are possible without other than minor changes in the male palpal structure. The Hawaiian thomisid species were listed by Simon (1900) in Misumena (6 spp.), Diaea (2 spp.), Syiaema (4 spp.), and Mecaphesa (2 spp.), but by Suman (1970) in Misumenops (14 spp), Synaema (1) and Mecaphesa (3 spp.). I have checked the type material of all Hawaiian thomisids preserved in the Bishop Museum and, in my opinion, both male and female genitalia of Syndema naevigerum Simon, 1900 are much closer to the genitalia of all Hawaiian ‘Misumenops’ than those of the type of Synaema, S. globosum (Fabricius, 1775) from Europe. The relative width of the ocular area is certainly a parallelism in true Synaema and the Hawaiian ‘Synaema’. The blunt setae of Mecaphesa s. str. have been independently modified, and the three species constitute a sister group of the Hawaiian ‘Misumenops’ and ‘Synaema’ together. The geni- tal organs of both sexes are again more or less similar and not at all related to Oxyptile or Heriaeus, as claimed by Simon (1900). Suman (1970) was not familiar with the Palaearctic thomisids and had no opinion on this matter, but be published useful drawings of the genitalia of all Hawaiian thomisids. This group of ‘Misumenops’ is also present in Japan, as Misumenops kumadai Ono, 1985 and in western North America at least 13 species (celer-group), listed by Schick (1965) in Misumenops (Misumenaps). Misumenops inclusus Banks, 1902 from Galapagos Islands and M. sjoestedti Berland, 1924 from Juan Femandez Islands are 388 MEMOIRS OF THE QUEENSLAND MUSEUM TABLE 1. Hypothesis of generic placement and zoogeographic origins of species groups of Thomisidae represented in Polynesia. additional members of this genus in the Pacific region. The generic name Misumenops is here reserved for the group of Neotropical species that are unambiguously related to Mf. maculissparsa (Keyserling, 1891), a species with a well developed tutacular process in cymbium and a complex of tibial apophyses that is widely dif- ferent from any Pacific species. M. pallens (Keyserling, 1880) and M. pallida (Keyserling, 1380) were recently revised by Rinaldi (1983) without comparison to the type species. These widespread Neotropical species are not close to M. maculissparsa, but they may remain in the same genus. On the other hand, the concept of Mecaphesa is here widened to also include most Polynesian, some other Pacific and many north American ‘Misuntenops’, the more plesio- morphic branch of this genus. ‘“Misuntenaps” rapaensis Berland (Berland, 1934) from the iso- lated Rapa Island with a terrestrial fauna of peculiar affinities probably belongs elsewhere. The widespread Holarctic M. trieuspidatus (Fabricius, 1775) is removed from this genus, but its final generic placement must wait for a more complete revision of Thomisinae: Misumenini. The structure of the male tibial apophysis, includ- ing the microstructure of its tip, is different from all other thomisids known to me, M. japonicus (Bosenberg and Strand, 1906) is a relative or even a member of Diaea, while the asperatus group of Misumenops (Schick, 1965) may belong to Metadiaea and the coloradensis group represents a distinct genus, not close to Mecaphesa or Misumenops. The synonymic history of Metadiaea is contus- ing, too, as the authors discussing this problem (Toledo Piza, 1937; Caporiacee, 1954; Rinaldi, 1983) have based their opinions on the data from Speices other than the type species, M. fidelis Mello- Leitao, 1929 from Minas Gerais, Brazil, [ agree with Rinaldi (1983) in transferring the other species to Misumenops pallida-group, but not the lype of the genus, and Metadiaea remains a valid American genus probably including also North American species. There is a widespread Southeast Asian-New (Guinean group with short scutate male abdomen and with genital organs of both sexes close to Runcinia, Their male tibial apophysis is similar to Mecaphesa, including the characteristic ribbed tip, The New Guinean Loxoporetes known only by the female is probably related te, or even congenenic with this group, of which most species have been described as Misumena. This group will probably be named Massuria Thorell, 1887 and it might be a plesiomorphic sister group of the widespread and widely sympatric Runcinia. POLYNESIAN THOMISIDS OF OLD WORLD OR AUSTRALIAN ORIGIN The greenish thomisids from Samoa and Tonga islands have been described as different species (L. Koch, 1874; Rainbow, 1902: New Hebrides; Strand, 1913), all referred to Diaea, A critical survey of several large populations reveals thal there is only one widespread species, 'D.” praetexta(L, Koch, 1865) with large infrapopula- tional! variation in the colour pattern, but quite small vanation in the structure of the genital organs. In contrast to east Polynesian and Hawaiian thomisids this species lives in the vegetation of lowlands and is also common in Fiji and Vanuatu. At least D, sticta and D. limbata (Kulezynski, 1911) within the widespread and common Melanesian Diaea spp. as well as the cast Australian D. multopunctata L. Koch, 1874 and D., prasita L. Koch, 1876 are congeneric with D. preetexta, This group of Australian-Polynesian ‘Diaea’ deserves generic status, but until some ‘old’ thomisine genera from the Indo-Pacific area have been revised the erection of a new genus would be hasty. The type species of Dinea, Araneus dorsatuy Fabricius, 1775, probably together with some other Palaearctic species has male and female genital organs resembling Heriaeus (Loerbroks, 1983). The deviating non- genitalic characters of Heriaews are adaptations to life in the desert. FHedana subtilis L.. Koch, 1874 was described from one male and a juvenile from Tonga, western Polynesia. Most probably it 1s not con- generic with the Australian type species H. gracilis L. Koch, 1874 and several other species POLYNESIAN THOMISIDAE from Southeast Asia to New Zealand. It has not been compared with the type of Tharrhalea from N. Australia, but it seems, at least, to belong to the same tribe as T. maculata from New Guinea. H, pallida Koch, 1876, described from juvenile specimens from Tonga most probably is a synonym of H. subtilis or even “D,” praefexta. In addition to these two yery old records there is also a recent record of a subadult female from Tonga. Hedana and Tharrhalea have been catalogued in Stephanopinae (Simon, 1895; Roewer, 1954: Bonnet, 1957), but ‘H.” subtilis belongs to Thomisinae. T have seen relatives of H. subtilis (? Thar- rhalea) in New Guinea and southeast Asia and the range of this unnamed group is more or less similar, but possibly extending farther northwards, when compared to that of the ‘Dinea™ praetexta-group. ZOOGEOGRAPHICAL CONCLUSIONS The Polynesian thomisid fauna has apparently arrived from two opposite directions, South America and Melanesia. These two elements are not known to be mixed in any part of Polynesia (map in Fig. 1). New World element (Mecaphesa) probably first arrived in Hawaii, where an explosive speciation has taken place, resulting in 17 known species (Suman, 1970: in three penera), most having a small range up in the mountains. Galapagos Islands (1 or several spp.) and Juan Ferandez Islands constitute another possible source of immigration for the East Polynesian Mecaphesa spp. They have further evolved to at least six, but probably more local endemics. There arealso sympatric montane species, atleast in the Marquesas Islands, but most probably also in Tahiti. The majority of East Polynesian species live on mountain tops, but a few species have occassionally been recorded also in lowland, The Oritental-New Guinean genus of the Miswnena-group, here tentatively called Mas- suria has not been found in the intervening Melanesian archipelagoes and must be excluded from possible sources of origin of the east Polynesian Mecaphesa, although both groups belong to Misumenini, a group probably older than any mid-Pacific archipelagoes. There are no known thomisids in the Central Polynesian tslands (Cook Islands, Tokelau Is- lands, Niue, etc.) (Marples, 1955b, 1957, 1960, 1964) or in the low coral islands north of Samoa (Rainbow, 1897; Roewer, 1944). In spite of addi- S89 tional collecting both in the lowland as well as in the mountains of Rarotonga by myself, no Mecaphesa spp. have been observed. The ab- sence Of Digea preetexta in disturbed lowland habitats of Raretonga seems to show thal anthmopechorous dispersal of this species is not very effective, although its frequency in the more western archipelagocs can be partly explained by this type of short distance dispersal. The Australian Thomisidae appear to have ar- rived through Melanesia, where Fiji and Vanuatu share the same common lowland species, ‘Diaea’ praetexte and several closely related species are present in New Guinea and Eastern Australia. The other west Polynesian thomisid specics, ‘Tharrhalea’ subtilis belongs to a group that has a wider range including southeast Asia. In spite of intensive field work in Samoa and Tonga during 1991-92, there are still no montane thornisids known in the western archipelagocs of Polynesia. There are some other Polynesian spiders of Neotropical origin (Anyphaenidae, some Thendiidae, etc.), but most spider familtes repre- sented in Polynesia are of Melanesian, southeast Asian or New Zealand origin. ACKNOWLEDGEMENTS This study is part of a long range programme on Indo-Pacific spiders, including field and muscum work during the last 20 years. This work has only been possible through the gencrous cooperation of numerous persons, who could not be listed separately here, Useful comments were also presented by two referees and an editor. The map was. kindly drawn by Ms. Maija Mustonen, and the original English text was checked by Mrs Alice Moore. LITERATURECITED BEATTY, LA. & BERRY. JW, 1988, Four new spocles of Parathenra (Araneae, Desidac) fram the Pacific. Jounal of Arachnology 16: 339-347. BEATTY. J.A.. BERRY. 3.W., & MILLIDGE, AF. 1991. The Linyphiid spiders of Micronesia and Polynesia with notes on distnibotion and habitats. 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ROEWER, C.F, 1944, Einige Araneen von Prof. Dr. Sixten Bocks Pazifik-Expedition 1917-1918, Meddelanden fran Géteborgs Museum Zoologis- ka Avdelning 104: 1-10. ROEWER, C.F. 1954. Katalog der Araneae von 1758 bis 1954, vol. IITA. (Institut Royal des Sciences Naturelles de Belgique: Bruxelles). SCHICK, R.X. 1965. The crab spiders of California (Araneae, Thomisidac). Bulletin of the American Museum of Natural History 129: 1-180. SIMON, E. 1895. Histoire Naturelle des Araignées, vol. 1(4): 761-1084. (Librairie Encyclopédique de Roret: Paris). 1900. Arachnida. Pp. 443-519, In, Sharp, D, (ed.), Fauna Hawaiiensis, or the Zoology of the Sandwich Isles, vol. 2. (Cambridge University Press: Cambridge). STODDART, D.R, 1968. Isolated island communities. Science Journal 4: 32-38. STRAND, E. 1913. Neue indoaustralische und polynesische Spinnen des Senckenbergischen Museums. Archiv fiir Naturgeschichte 1913 A 6: 113-123. SUMAN, T.W. 1970. Spiders of the family Thomisidae in Hawaii. Pacific Insects 12: 773- 864. TIKADER, B.K. 1980. Thomisidae (crab-spiders). The Fauna of India, Araneae, vol. 1, part 1: 1-247. TOLEDO PIZA, S. 1937. Novos Thomisidos do Brazil. Folia de Clinic. Biologia, Sao Paulo 9: 179-183. WILSON, J. TUZO, 1963. Continental drift. Scientific American 208: 86-100. SCORPION DISTRIBUTION IN A DUNE AND SWALE MALLEE ENVIRONMENT N.A-LOCKET Locket, N.A, 1993 11 11: Scorpion distnbution in a dune and swale mallee environment. Memoirs of the Queensland Museum 33(2); 593-598, Brisbane, ISSN 0079-8835, A system of stable and vegetated dunes, separated by occasionally flooded swales, contains populations of six scorpion taxa. Urodacus yaschenkai (Birula) digs deep burrows in the soft soil of the dunes, but the shallower burrows of U. armarus Pocock are concentrated at their base, extending onto the swale for ca. 50m. Lychas jonesae Glavert, L. verriatus (Thorell) and lsometroides angusticaudis Keyserling occur on the swale but not the dunes. Cer- cophonius kershawi Glauert has occasionally been found in litter beneath mallee trees on Lhe dunes. Soil hardness may account for U. yaschenkoi occurring only on the dunes. fsometroides, a spider predator, occurs where spider burrows are found. Predation by the larger Uradacus may account for the buthids not extending onto the dunes.- Scorpions, Australia, ecology, habitat. N.A. Locket, Department of Anaiamy and Histology, University of Adelaide, Bax 498, GPO, Adelaide, South Australia 500), Australia; 3 November, 1992. An area of scrub near Berri in the South Australian Riverland consists of a series of stable dunes bearing mallee trees and shrubs inter- spersed with flat grassy swales, which show signs of occasional flooding. This locality contains a pulation of Urodacus yaschenkoi, Blacklight- ing on and between the dunes showed that five other scorpion taxa are present in the area but not uniformly distributed. Observations are now presented on these populations and their distribu- tron across the dune- swale system. Two of the taxa found do not accord with the descriptions given by Koch (1977). One, a Lychas, corresponds to Glaucr's (1925) unil- lustrated description of L jonesae, apparently froma single specimen collected near Kalgoorlie, Western Australia, Koch (1977), who examined the holotype, included L. jonesae in L. mar- mores but did not give reasons for doing so. The present specimens resemble L. alexandrinus, widely distributed in arid Australia (Koch, 1977, map 4), but differ significantly from it and from L. marmoreus. They agree closely, except in colouration, with the (markedly faded) type of L jonesae. An illustrated redescription of L. joresae is in preparation, and the present specimens referred to that species meanwhile. The other belongs to the genus Jsemetroides, which Main (1956) suggested was monospecific, all specimens being referable to . vescus, a view supported by Koch (1977). The Beri specimens agree better with the descriptions of Keyserling (1885), Kraepelin (1916} and Glavert (1925, 1963) of J. angusticaudis, and are certainly not typical of 4 vescus. An account of the genus Isometroides is in preparation, and the present specimens referred to /, angusticaudis in an- ticipation of that work. Many factors influence the distribution of scor- pions, including latitude and climate, type of terrain and soil hardness. Biotic factors such as intra-guild competition and predation are also important (Polis, 1990). The latitude of the study site, ca 34°, is within the range of maximum scorpion diversity, given by Polis (1990) as 23- 38°, Within this beltup toca LO species may occur sympatrically in the northern hemisphere, though most locales have only 3-7. Diversity is greatest in deserl regions, with 24 of the 2& communities of six or more being io subtropical deserts, where terrain may range from loose sand to hard packed stony ground, Soil hardness was closely related to Species distribution in Opisthophthalmus by Lamoral (1978). Bradley (1986) showed that populations of the burrowing Paruroctonus utahensis were denser on soft soils than hard, and that its burrowing was impaired by the hardening of the soil due to rain. Vegetation patterns corre- lated both with soil type and scorpion population, but areas with different scorpion densitics con- tained similar biomass of potential prey, Bradley also demonstrated the destruction caused by flooding to a population of P. urahertsis. Polis (1990) shows that biotic factors may well affect the composition and balance of a popula- tion, He gives strong evidence on the important influence of scorpions on the community in which they live, by competition through preda- tion on other invertebrates or cannibalism of smaller scorpion species, and of smaller con- §pecific instars. Individual scorpions of different species but similar size may well compete direct- 594 Berri, rainfall 40 50 mmrain, mean * mmrin, median } Days of rain a ee JFMAMJJASOND Month 20 Berri, max. and min, temperatures 40 30 y H 20 > Max,."C a > Min, °c 5 40 0 JFMAMJJASOND Month FIG. 1. Temperature and rainfall, Beri (nine year average). ly for food, since most are generalist predators, perhaps leading to one species becoming dominant. Different sized scorpions may take different groups of prey, based on size, though the young of a large species may compete directly with adults of a smaller when the individuals are of comparable size. METHODS The site is about § km NNE. of Beri, 140°38’E, 34°13°S, in the South Australian Riverland. The climate at Berri is warm and dry (Fig. 1). A transect 10m wide was laid out from dune to dune across aswale, some 300m. The nature of the soil was noted, and trees and shrubs more than a few cm high plotted to the nearest 1m. Single-, or on one occasion two-day, visits were made to the study site on fourteen occasions, on moonless nights when possible, between March 1989 and May 1992. On each visit the MEMOIRS OF THE QUEENSLAND MUSEUM [Date | U.yusch. | U.carmat. | angust._|1.variatus | Ljomesae| isserg9_f0__1o___f4__{o_to_ oaMargo |e fafa fo a a TABLE 1. Catches of scorpions, blacklighting only. parts of the transect containing the characteristic burrows of Urodacus yaschenkoi were noted. On one occasion in summer all the burrows within the transect were marked with numbered tags. Burrow identification was confirmed and specimens obtained by trapping burrows away from the transect, The traps were plastic vending machine cups, ca 200cc capacity, dug into place al the burrow mouth, the burrow opening directly at the lip of the cup, The traps were visited at least ih after sunset, when scorpions had emerged from the burrows and fallen into the cup. Smaller burrows, without the curved entrance of U. yaschenkoi, were identified as those of U. armatus by digging out the scorpion. On three occasions U. armatus was identified by black- light at a burrow mouth which was then marked and examined next day. Blacklighting was carried out, away from the transect but within the dune-swale system, on each visit by two persons, working parallel to each other and approximately 100m apart. Black- lighting, commencing at various times after sun- set, On SOMe Occasions as soon as it became dark enough and on others up to 1.5h after sunset, was continued for ca 2h. Uredacus yaschenkoi and U. armatus could be distinguished in the field by blacklight. lsometroides, except very small individuals, was distinguishable from the Lychas species, but the two Lychas could not be told apart until the catch was examined indoors. This took place on return from the field, when notes on weather, capture sites and behaviour were written, Detailed plots of specimen location were not made, but it was possible to assign the taxa to dune, dune base or MALLEE SCORPION DISTRIBUTION i re social 4 ewer | = L> - 595 FIG. 2, View of transect across swale, looking north from southern dune, |, sandy soil al base of dune, 2, low bank beside old track, 3, track. 4, swale. 5, far dune. See also Figs 3 and 4- swale, Identifications were confirmed on return to the laboratory. RESULTS The transect, running N-S, extends 300m from the top of one dune, ca 6m high, across the flat swale, to the top of the next dune (Fig. 2). The dunes bear scattered mallee trees, Eucalyptus oleosa and E. brachycalyx, numerous bushes of native hop, Dodonaea sp., and clumps of Spinifex. The swales are lightly covered with grass and other low plants, with sparse bushes of native hop and of Cassia nemephila var. platypoda (Fig. 3). Catch data are summarised in Table 1 and distributions in Fig. 4. Urodacus yaschenkoi bur- rows occur on the dunes, mainly in the open but a few under light cover. In January 1991, 80 burrows were located and marked within the tran- sect, but by October, 56 tags either were not related to a visible burrow or had been disturbed by animals, Of the three WV. armatus burrows marked while blacklighting, two had been closed by next day, and would have been missed apart from the marker. No further attempts were made to trace the fate of individual burrows. Individual U. yaschenkoi, usually adult males, were found by blacklighting in December-February, mainly on the dunes but including one ca. 50m onto the swale. U. yaschenkoi were also observed at their burrow mouths by blacklight in summer. Uredacus armaius burrows were occasionally found on the dunes, but most were at the dune base and for up to 50m onto the swale. U/. ar- matus, mostly immature, found by blacklight had a similar distribution , with occasional examples up to ca 100m onto the swale. Immature in- dividuals have sometimes been found clinging to low vegetation within a few cm of the ground, L/, armatus, recognisable by blacklight from U. yas- chenkoi by their squat pedipalps, have been seen at the burrow mouth between October and February Three species of buthid, Lychas jonesae, L, variatus and Jsometroides angusticaudis have been found, only on the swale, by blacklighting- L. jonesae, commonest overall, though on oc- casions outnumbered by I. angusticaudis, occurs all across the swale, but often near low vegetation near the dune base. Some have been found cling- ing to stems within a few cm of the ground, 596 100 200 ;>———__+ 300 -bL --~ -| Track 4 oO. o °o a ee ° 90 R25 ° oe 8 2° oS B a Dune ° 180 1 AS baa -| Old track Pp , 270 150 5 _| Track ° oF oo 30|* ° | r ©0 0 be 8 ce 120 ry a 210 *t! Dune fe] 0° Spinifex § Eucalyptus brachycalyx 1 Eucalyptus oleosa 2 Dodonaea sp. * Cassia nemophila var platypoda 0 FIG. 3. Plot, to scale, of distribution of major plants across transect. Distances in metres. mostly head down, but none have been found high in bushes. Lychas variatus has been taken occasionally, never more than two and frequently none, in an evening. Insufficient have been found to com- ment on their distribution on the swale. Isometroides angusticaudis has mostly been found on the surface by blacklight, among low grass rather than taller vegetation and extending up to but not above the dune base. A few have been dug by day from the burrows of lycosid spiders, abundant on the swale but not the dunes. One Cercophonius kershawi (identified from Acosta (1990)) was found in May 1992 by kick- ing over leaf litter beneath mallee trees while blacklighting. (Two juvenile Lychas variatus were caught in the same way on dunes within 1 km of the transect in June 1987). MEMOIRS OF THE QUEENSLAND MUSEUM U. yaschenkoi a DUNE = >270 Track 210 Isometroides —— 180 SWALE Lychas jonesae Lychas variatus Spider burrows ___ 459 120 Track 90 A5 SS ‘pee D> = == Old track ti 7 mek “E65 — 30 DUNE U. yaschenkoi — Om FIG. 4. Distribution of scorpions across dune and swale system. Urodacus yaschenkoi occurs on the dunes, U. armatus at their bases and the three buthids on the swale. DISCUSSION Many labels in collections state a locality, without details of microhabitat. The population disparity now described from localities a few meters apart suggests that it may be helpful to define localities more precisely. Lamoral (1978), studying two burrowing MALLEE SCORPION DISTRIBUTION species of Opisthophthalmus, found clear separa- tion of two otherwise sympatric species, strongly correlated with soil hardness, a factor probably also important in Urodacus. Koch (1978) found the depth and tortuosity of Urodacus burrows within a species greater with aridity. There is also a species difference: U. yaschenkoi and U. hoplurus dig deeper and more spiral burrows than U. armatus. Koch (1981) noted that Urodacus scorpions show little correlation with soil type, but more with softness and the chance of reaching water by burrowing. Shorthouse (1971), Shor- thouse and Marples (1980) and Koch (1978) have described the spiral burrows up to Im deep of U. yaschenkoi in loose sandy soil. The dune soil at Berri is of this type. Most burrows of U. armatus, seldom more than 30cm deep, are in the firmer soil at the dune base and swale, though some occur up the dunes, in what appears otherwise to be U. yaschenkoi territory. Koch (1981) considered three Australian zones, a moist temperate southern, semi-arid to desert central and humid tropical northern, as- sociating various scorpions with these zones: Uredacus yaschenkoi and U. armatus he regarded as mainly central forms. He found scor- pion distribution not correlated with vegetation type, single species occurring in a wide range of habitats. He suggested that range-determining factors include temperature, precipitation and biotic factors, e.g. competitive exclusion. He also examined morphological characters, suggesting that large size, longer metasomal segments and spines, more granulation, and higher pectine tooth counts are aridity-linked in Urodacus, while large size, light colouration, more granula- tion, higher pectine tooth counts and a less prominent subaculear tooth are aridity- linked traits associated in Lychas. He regarded Isometroides as showing the culmination of these buthid traits. Of the sympatric species at Berri, both Urodacus are pale and smooth, their pectine counts largely overlap, but U. yaschenkoi is large and U. armatus small. L. variatus and I. angus- ticaudis are both pale but mottled though L. jonesae is small and dark, with subaculear tooth intermediate between the other two buthids. The swale, where /sometroides has been col- lected by blacklight, contains numerous lycosid spider burrows, up to 30cm deep in hard soil. Isometroides was recognised by Main (1956) as a spider predator and collected by her from their burrows. Four have been so collected in the present study, but no concerted digging has been done. 597 The habit of clinging to vegetation close to the ground, also observed in immature U. armatus by G.T. Smith (personal communication), may enable scorpions to avoid wandering predators. Some scorpions, e.g. Centruroides exilicauda in America, are frequently found in bushes well off the ground, but such climbing has not been seen in the present case. The total catches of buthids suggest that Lychas jonesae is dominant on the swale, though on occasions more /sometroides have been caught. L. variatus is much less common than either. Isometroides is known to be a specialist burrow- ing spider predator. Probably the Lychas species are less specialised, though little is known of their diet; one instance of L. jonesae eating an imma- ture U. armatus was the only act of predation observed. Insufficient is known of the habits of the two Lychas to indicate why the smaller should be commoner. ACKNOWLEDGEMENTS I thank Deirdre Locket and G.R. Johnston for assistance in the field and with plant identifica- tion and Rae Sexton for assistance with plant identification; Dr D.C. Lee (South Australian Museum), Dr A. Yen (Museum of Victoria) and Dr M.S. Harvey (Western Australian Museum) for access to specimens in their care; and the Bureau of Meteorology for climatic data. LITERATURE CITED ACOSTA, L.E. 1990. El genero Cercophonius Peters, 1861 (Scorpiones, Bothriuridae). Boletin de la Sociedad de Biologia de Concepcién (Chile) 61: 7-27. BRADLEY, R.A. 1986. The relationship between population density of Paruroctonus utahensis (Scorpionida: Vaejovidae) and characteristics of its habitat. Journal of Arid Environments 11: 165- 172 GLAUERT, L. 1925. Australian Scorpionidea. Part 1. Proceedings of the Royal Society of Western Australia 11: 89-118. 1963. Check list of Western Australian scorpions. Western Australian Naturalist 8: 181-185. KEYSERLING, E. 1885. Part 32. Pp. 1-48. In Koch, L. and Keyserling, E. ‘Die Arachniden Australiens nach der Natur bescrieben and abgebildet’. (Bauer & Raspe: Niirnberg). KOCH, L.E. 1977. The taxonomy, geographical dis- tribution and evolutionary radiation of Australo- Papuan scorpions. Records of the Western Australian Museum 5: 81-367. 1978. A comparative study of the structure, function and adaptation to different habitats of burrows in 598 the scorpion genus U/rodacus (Scorpionida, Scor- pionidae). Records of the Western Australian Museum 6: 119-146. 1981. The scorpions of Australia: aspects of their ecology and zoogeography. Pp. 875-884. In Keast, A. (ed.), ‘Ecological biogeography of Australia’. (Junk: The Hague). KRAEPELIN, K. 1916. Results of Dr E. Mjéberg’s Swedish scientific expeditions to Australia 1910- 1913. 4, Scolopendriden und Skorpione. Arkiv fiir Zoologi 10: 1-43. LAMORAL, B.H. 1978. Soil hardness, an important and limiting factor in burrowing scorpions of the genus Opisthophthalmus C.L. Koch 1837 (Scor- pionidae, Scorpionida). Symposia of the Zoologi- cal Society of London 42: 171-181. MEMOIRS OF THE QUEENSLAND MUSEUM MAIN, B.Y. 1956. Taxonomy and biology of the genus Isometroides Keyserling (Scorpionida). Australian Journal of Zoology 4: 158-164. POLIS, G.A. 1990, Ecology. Pp. 247-293. In Polis, G.A. (ed.), ‘The biology of scorpions.’ (Stanford University Press: Stanford). SHORTHOUSE, D.J. 1971. ‘Studies on the biology and energetics of the scorpion Urodacus yaschenkoi.’ (Unpublished Ph.D. Thesis, Australian National University: Canberra). SHORTHOUSE, D.J. & MARPLES, T.G. 1980. Obser- vations on the burrow and associated behaviour of the arid zone scorpion Urodacus yaschenkoi Birula, Australian Journal of Zoology 28: 581- 590. FROM FLOOD AVOIDANCE TO FORAGING: ADAPTIVE SHIFTS IN TRAPDOOR SPIDER BEHAVIOUR BARBARA YORK MAIN Main, B,Y, 1993 11 11: From flood avoidance to foraging: adaptive shifts in trapdoor spider behaviour. Memoirs of the Queensland Museum 33(2): 599-606. Brisbane. ISSN 0079-8835, Fossorial habits protect many mygalomorph spiders from both biotic and environmental factors. However burrows in some habitats are vulnerable to sheet flooding. Spiders in diverse habitats counter the hazard of flooding in various ways. A comparative account of adaplive specialisations, particularly of burrows, in flood avoidance is presented. Such primury modifications sometimes lead to new foraging opportunities. Examples are given of modified foraging as a consequence of burrow adaptations. The origins of such constructions are hypothesised in relation to changing climatic regimes and modified habitats. The idiopid genera Hamogona Rainbow and Neahamogona Main are restored from synonymy. OiMyzalomerphae, Trapdoor spiders, burrows, flood avoidance, foraging, Ausiralia, Barbara York Main, Zoology Department, University af Western Ausralic, Nedlands, Western Ausiralia 6009, Ausiralia; 5 November, 1992, Most mygalomorph spiders are terrestrial and either make burrows, silk tubes or webs or com- bine a web with a burrow, A few are arboreal and either make tubes in the bark of trees or have webs in crevices or under bark; their nests are generally nel associated with foliage. Of the 15 currently recognised families of Mygalomorphae (Raven, 1985), 10 occur in Australia and of these, seven have at least some representatives with trapdoors. & burrow provides protection from the physical environment, from weather conditions and from predators and parasites; it provides 4 brood cham- ber for eggs and spiderlings. A burrow is also a lair from which a spider perceives and ambushes or intercepts prey; thus it provides a foraging base. All these functions. have been commented on many times in the literature over the last century, the earliest comprehensive study possib- ly being that of Moggridge (1873, 1874). In its simplest form a burrow has an ‘open’ entrance from which a spider makes short sorties in pursuit of prey. In extreme habitats, the en- trance may be sealed with silk or soil for added protection during certain times of the year, for example during summer drought or winter snow falls. Folding collars and finally hinged doors give maximum Security and protection. The pro- tective advantage of a door has been shawn to be offset by the hinge-line inhibiting the foraging area of a spider but nevertheless many door build- crs have overcome this disadvantage by various modifications to the burrow (Coyle, 1951; Main, 1986). This paper discusses the adaptive behavioural responses associated with nest structure and site, of Australian mygalomorph spiders, to the hazard of flooding and shows thal these primary adapltu- tions have sometimes secondarily created new foraging opportunijies fer spiders. In panicular the previously unreported nest of an undescribed species of Amare which exhibits both ‘primary’ and ‘secondary’ responses in its flood-ayoidence tactics is described also. FLOOD AVOIDANCE BEHAVIOUR In certain terrestria) habitats, burrows and silk lubes and webs face the physical hazard of flood- ing. Generally the complexity of habitats in rain- forest ancl mesophyll forest provides some sort of buffer against flooding; there is greater capacity for absorption of rainfall in the vegetation and litter of a forest Moor than there is for example in desert or semi-arid country where sheet flooding on bare ground is a common phenomenon, Even so some rainforest situations are subject to water logging and flooding asscciated with torrential downpours. Likewise whererain is markedly sea- sonal] as in monsoon rainforests the alternation of Wet and dry conditions means that some habitats experience sudden saturation or inundation. Main (1976, 1982b) and Cloudsley-Thompson (1982, 1983) discussed some of the burrow modifica- tions of mygalomorphs which prevent flooding. Avoidance of flooding is different to behaviours whereby spiders withstand immersion by enclos: ing the body in a bubble of air. In summary, in avoiding flooding of nest siws, mygalomorph spiders have adapted behavioural- ly in several ways: (1) By moving the nest site—behaviour prior Lo, during or after the event. 600 SURFAGE FORAGING Sl Wese\ IL C) FIG. 1. Flood avoidance specialisations of mygalo- morph burrows: (a) soil and pebble levee of Kwonkan wonganensis;, (b) bath plug door (Idiopidae); (c) dome or ‘cap’ of an Aganippe species (Idiopidae); (d) ‘sock’ of Anidiops (Idiopidae); (e) ‘pebble’ and collar closure of burrow of Stanwellia nebulosa (Nemes- iidae); (f) side shaft and escape ‘hatch’ of burrow of Aname diversicolor (Nemesiidae); (g) side shaft with door in nest of /diommata sp. (Barychelidae); (h) profile of nest of a Teyl sp. (Nemesiidae) with en- trance atrium and subterranean doors (and sideshaft): (i) aerial tube of Misgolas robertsi (Idiopidae) sup- ported on tree trunk; (j) extended tube with trapdoor of Aganippe castellum (Idiopidae) supported against stem of shrub; (k) silk and soil tube of ‘turret-build- ing’ Aname sp. (Nemesiidae) in foliage of shrub. (2) By permanently reinforcing the nest e.g. burrow (and/or opening) against inundation—pre- vention. (3) By modifying the nest structure so that part of it is safeguarded against inundation—preven- tion. (4) By modifying the nest so that it is (in part) sited beyond the reach of intermittent flooding— prevention. MEMOIRS OF THE QUEENSLAND MUSEUM (5) By adopting an arboreal instead of ter- restrial habitat. Examples of these adaptations will now be given. (1) Mygalomorphs elsewhere have been re- corded as moving nest sites prior to inundation. The Amazonian web-weaving diplurid /schno- thele guianensis makes webs on tree trunks in the rainforest which is seasonally inundated. Spiders move their web sites higher up the trunks as the water level rises (Hofer, 1991). The Australian diplurid genus Cethegus (curtain web spiders), which makes copious webs sometimes associated with a burrow retreat, amongst stones, or against logs or shrub stems, is widespread across tropical Australia, the interior and southwestern Western Australia (Main, 1960, 1991a and unpublished; Raven, 1984). A study ona species at Durokoppin in the Western Australian wheatbelt showed that the spiders move their web sites after rain damage (Main, unpublished). Another species which oc- curs amongst the rocks of water courses in the Kimberley rainforest patches (Main, 1991a) pre- sumably moves web sites during the ‘wet’ when the habitat is inundated. Although dependent on a web for prey capture these spiders are remark- ably agile on the ground, and thus could readily decamp if flooded out of their nest sites, follow- ing which a web could be readily reconstructed (unlike some architecturally complex burrows of other mygalomorph families). : (2) Even ‘open’ burrows, if lined with silk frequently have collapsible or folding collars which can prevent flooding, for example as in many nemesiids and some Misgolas species, e.g, M. pulchellus (Rainbow & Pulleine) (pers. obs.). Collars are sometimes strengthened with litter or by a surrounding pile of soil or silk-bound peb- bles (Fig. 1a) e.g. the levees of some nemesiids including Kwonkan wonganensis (Main) (orig- inally described as Dekana (Main, 1977, plate 15)) (see also Main (1981, plate 1, fig. d) with reference to the levee of a ‘diplurine’ burrow). The ctenizid Conothele, the actinopodid Mis- sulena and some barychelids have secure doors and parchment or canvas-like, silk linings which are more-or-less impermeable. Most idiopid species construct well defined burrows and all except some species of Homogona', Neo- homogona’ and Misgolas have a trapdoor. Many idiopid species which have adapted to flood- prone habitats, ranging from rainforest to desert 'The idiopid genera Homogona Rainbow and Neohomogona Main were synonymised with Cataxia Rainbow by Raven (1985). They are here formally restored from synonymy and diagnosed in Main (1985). FLOOD AVOIDANCE IN TRAPDOOR SPIDERS and particularly in bare ground or sloping creck banks, frequently have permanently reinforced burrows including thick plaster walls coated with dense silk, and thick, close fitting bath-plug like doors or tightly fitting caps (Figs Ib, ¢). Such secure nests also provide protection against predators, parasites and adverse physical condi- tions, including dessication. (3) Some species of Idiopidae, Nemesiidae, Barychelidae and Hexathelidae safeguard par- ticular areas of their burrows against mundation, Such safeguards include (a) special biocks in the lumen or (b} sideshafts with ‘escape’ hatches or (c) one or more sidechamhers with ‘intemal’ trap- doors. Examples of the above are: (a) Some species which have either an open entrance (e.g., Misgolas spp.) or a flimsy door (¢,g., Anidiops) have a collapsible collar (‘sock', sec Main, 1957. 1976, plate 9 and 1985, figs 209, 210) consisting of a detachable section of the silk lining which can be pulled downwards by the spider thus blocking the burrow (Fig. Id). Water seeping down the walls or flowing into the bur- row is deflected by the infolded ‘neck’ of the sock and soaks into the surrounding soil leaving the Jower section of the silk lined burrow unflooded. A similar structure in Stanwellia nebulosa (Rain- bow & Pulleine) (Fig, le) is further reinforced by an attached, artificial pebble which seals the lower silk lined part of the burrow (Rainbow & Pulleine, 1918, pl. 20; Main, 1964, 1972 figs 22a, b, 1976). Although these devices are generally considered a projection against predators (see Main, 1956a regarding Anidiops (=Gaius) their original function was probably prevention against flooding (see Main, 1976 regarding Stan- wellia). (b) Nests of some species have silk sideshatfts with ‘escape’ hatches at the surface (see Fig. If) which probably enable the spiders to escape flooding as well as intrusive predators. Examples are the burrows of “wishhone” spiders of the genus Anan (Main, 1982a, fig. 1; 1976, pl. 10) and Misgolas ornate (Rainbow) (Main, 1985: 33). (c) Sideshafts with ‘internal’ trapdoors are con- structed by several undescribed species of Tey! (Nemesiidae) (earlier altributed to Jxamaius, see Main (1976, pp. 86-88, fig. 21)), by Hadronyehe (Hexathelidae) (see Main, 1964:40, fig- j; 1976, fig, 18c; Gray, 1984, fig. 31 (described as Atrax)), Idiommata (Barychelidae) (Main, 1976, fig, 19d; Raven & Churchill, 1991: 35) and Missulena (Actinopodidae) (Main, 1956b), While the sideshafts of all species studied are known to 1 function as brood chambers and also sometimes #s protection from predators it is probable that the original function was that they offset flooding of the main shaft of the burrow {see Fig. 1g). Con- sidering the habitat of Tevi species this is une- quiyocal. (4) Burrows of some species are continued as tubes above the ground or Jitter surface and may be strengthened into free standing palisades (b the attachment of leaves, twigs and debris) which deflect sheet flooding in bare pround or prevent immersion in water-soaked litter. Examples in- clude the tubes of Homogona cunicularius Main (Main, 1983, fig. 15), Misgolas hirsutes (Raim- bow & Pullcine) (pers. obs_) and Neohontogana Airling! and N_ bolzanupensis Main (Main, 1985, fig. 219), ‘Tl'vbes that extend a considerable uis- tance above the substrate are attached to rocks. tree buttresses, exposed roots e.g. Misgolas robertsi (Main and Mascord) and related species (Main and Mascord, 1974, pl. La, b; Mascord, 1970 pl. 2 fig. 4), logs e.g, Cataxia maculata Rainbow (Main, 1969, figs 30, 3)) or stems of shrubs e.g. Aganippe castellum Main (Main, 1986, figs 2, 43: 1987 fig. 6). The first examples have open tubes, sometimes with flanged, collap- sible collars but A. castellunr has u trapdoor (Figs li, j). All are effective in flood avoidance by having the entrance above the ‘flood level’ fol- lowing a deluge. The previously undescribed but remarkable burrow/lube of an undescribed species of Anume extends asa turret-like tube amongst supporting foliage of shrubs. The genus Ananre which is widespread but endemic in Australia and Tas- mania, occurs in Varied habitats, is taxonomically diverse and includes many undescribed species- The turret-building species occurs in semi-arid country in southeastern Western Australia and Eyre Peninsula in South Australia, Nests have been observed in mallee/spinifex associations (EucalyptustTriodia) (Figs 2a, b, c) but also in mulga and amongst cheaopod shrubs in seasonal- ly swampy habitats. The spiders make shallow burrows lined with silk which extend as tubes into the foliage of supporting tussocks or shrubs and open either within the foliage or above the canopy (Fig. 1k). The outside of the tube is heavily but irregularly coated with soil. During and after rin, sheet flooding occurs in such sites, and particular- ly in the sandy loam of mallee/spinifex associi- tions, Water flows in a slurry around the spinifex hummocks. Burrows appear to be deepened (and/or remade) after rain and the sodden spoil dumped on the lip of the tube and outside the Subterranean | burrow) FOSSORLAL Elevated Siting of burraw PRIMARY ADAPTATION I SECONDARY ADAPTATION in Fload avoidance through modified burrow F . Specialised foraging inresponse to cpening_ [Shakers voeh miistbavow [nna aging | St open’ hurraws: collars folding collars levees |surface | —closed* burrows: reinforced walls & doors —sub-surese closures of lumen (open or closed —supemuamerary Chambers with doors a pitfall captures) extension of open tubes against vertical support [ —0.05). However, after two further matings (3 or 4), intraspecific predation increases significantly to 33% (p<0.05) if compared to a male which mated only once. However, the male is not always the victim. In C. reichlini Schenkel, males and females can mate several times without cannibalism (Hengmei and Hongquan, 1987). Equally, in in- teractions of C. cainbridgei L. Koch, no can- nibalism occurred between virgin males and females during the 38 interactions studied (Pol- lard and Jackson, 1982). Generally, species of Clubiana do not seem to be very aggressive 6) —t Ave Out breading-nest += Death by cannibalism Other monatity Number of fuyenties FIG. 3. Survival of juveniles (2nd instar) of C. cor- ticalis during 12 days after dispersal, without prey. toward each other during mating. Apparently, to eliminate cannibalism in C. corticalis, males and females should be brought together at about 13°C and individuals should be kepi paired for about 24 hours. Furthermore, the presence of prey at 13°C should make the cohabitation of males and females perfectly feasible for several days without intraspecific predation occurring. Such conditions during mating should minimize the manpower needed and lower production costs. CANNIBALISM AFTER DISPERSAL Juveniles leave the breeding-nest, built by the female, after 1-4 days. Then, they remain grouped around the nest for about 2-3 days before disper- sal. This gregarious phase lasts 17-20 days at 20°C (15-17 days in the breeding-nest and 2-3 days around the nest) (Fig. 1). [ris only from the juvenile instar 2 (as defined by Canard, 1987), that juveniles begin to hunt. Until leaving the breeding-nest juveniles use on their vitelline reserves and, some attack the undeveloped eggs in the nest. Indeed, weight differences between juveniles leaying the breeding-nest indicate the existence of trophic activity in some individuals, as there are no significant weight differences known to occur between eggs in the same batch in the spider (Lecaillon, 1905). Furthermore, this trophic activity does not seem linked to the female feeding her juveniles by regurgitation or the consumption by the juveniles of a wophic egg-mass as, for example, in Amaurobins (Amaurobiidae) {Tahiri ef al., 1989). At this point, mortality is the highest in many species (Austin, 1984), It may be even more delicate ina captive breeding situation as the juveniles, in large numbers in the cages, would devour each other, The dispersal of the juveniles given prey can MEMOIRS OF THE QUEENSLAND MUSEUM Aine Out of breeding: nest Death by cannibalism Other mortality Number of juvenites 0 7 = 3 . = 5 Days FIG. 4. Survival of juveniles (2nd instar) of C. cor- ricalis in the presence of prey. spread over 4 days (Fig. 3), There was no sig- nificant difference between the cages with a female and those with one removed {p>0.05). Thus, females did not attack their own progeny after dispersal for at least the first 12 days and on the condition that prey was available. Can- nibalism between the juveniles first began 3-4 days after the first dispersal and coincided with the expression of the first agonistic behaviour observed. Next, the number of juveniles decreased until there are about 10 individuals per cage towards the eleventh day. When the juveniles were fed Drosephila (Fig. 4), the female's influence on this period of her progeny’s development was similar. On the other hand, intraspecific predation was almost non-ex- istant in the first @ days and continued to be minimal afterwards, being about 5% after 10 days. There is a highly significant difference be- tween the two groups after the 12 days of study (p<0.001). Thus, with prey in the breeding cage. cannibalism decreased and was almost eliminated. Rypstra (1983), likewise, found in several spider species that intra-individual tolerance increased and cannibalism decreased when maintained at extremely high prey levels. Also, Krafft et ai. (1986) were able to prolong the juvenile social period by giving juveniles abun- dant food. Austin (1984) recorded a high mor- tality in the breeding of C. robusta, cannibalism heing one of the two major causes of mortality. On the other hand, in nature, spiders, which are potential prey of the highest density in the en- vironment, only represented only 3% of prey actually consumed (Austin, 1984). Austin sug- gested that the highest mortality occurs st the dispersal instar, The rest of the development presents fewer INTRASPECIFIC PREDATION IN CLUBIONA CORTICALIS Authorit jackson & Poulsen (1990) arman & Jackson (1985) iritani et al. (1972) Kiritani et al. (1972) Edgar (1969) Schaefer (1974 Yeargan (1975) Schaefer (1974) Gerhardt (1924), Bristowe (1941), Czajka (1963), Canard 1984) Genus or species b map picta a s Taieria erebus Oedothorax insecticeps Lycosa pseudoannulata Pardosa lugubris P. purbeckensis °o ‘0 P. ramulosa Pirata piraticus Mime | Ero aphana*, E. furcata* = = 3 Mimetus maculosus*, M. sp.* Jackson & Whitehouse (1986) Oxyo Turmer (1979) Phol | Holocnemus pluchei Blanke (1972) Fas Jackson & Brassington (1987), Pholcus phalangioides* Jackson & Rowe (1987) Brettus adonis°*, B. cingulatus°’* Jackson & Hallas (1986a) Jackson (1990b) jackson (1989) jackson & Hallas (1986a) Jackson (1990c) Jackson (1985a) Jackson (1990d) Cocalus gibbosus = Cobanus mandibularis Cyrba algerina®* C. ocellata®* Gelotia sp.°* S isa} 8 = $ Rg 8 = iS} 5 le BY : queenslandica” Jackson (1988a) Phaeacius malayensis, P. | Jackson & Hallas (1986a), sp. Jackson (1990a) Plexippus paykulli Jackson & Macnab (1989) Phidippus johnsoni Jackson (1977) Jackson & Hallas (1990) Jackson (1982a, 1986b), Jackson & Blest (1982), Jackson & Hallas (1986b), Jackson & Wilcox (1990 Portia fimbriata’* ae ney P. Jackson & Hallas (1986b) P. labiata®*, P. shultzi°* _| Jackson & Hallas (1986b Simaetha paetula Jackson (1985b) Tauala lepidus Jackson (1988b) ion ” Nentwig (1985) Achaearanea camura Jackson (1988b) Rypstra (1986) | [Rhomphaea | Enders (1974) TABLE 1: Literature review of araneophagic spiders: species principally or strongly araneophagic. *, ‘ag- gressive mimicry’ = to perform a variety of vibratory behaviour in which the prey-spider responded as it normally would to its own prey. °, oophagy. problems of cannibalism. Six groups of juveniles were bred together with 5 per Petri dish from instar 2-6 and no cannibalism was noted. Further- more, the periodic absence of prey during a few 611 [Family __|Genusorspecies _ [Authority | Mare (1992) pare Olios digna ,0. Heteropodidae | /lamargki ,O. obesulus | Jackson (1987) O. sp. Torthotiiele Jackson & Pollard (1990) antipodiana | | Myrmarachne lupata | Jackson (19826) | TABLE 2: Literature review of araneophagic spiders: species which are little or not araneophagic. *, species kleptoparasitic which are not araneophagic. days (3-5) in the cages did not result in in- traspecific predation, but behaviour of escape and avoidance was observed. Similar observations had been made on sub-adults and adult females bred at 25-30 individuals per cage (30x20x20 cm) over 2 months. Therefore, in breeding C. corticalis, the provision of Drosophila to juveniles at the disper- sal stage should be sufficient to eliminate in- traspecific predation. Then, 5 days after dispersal when all juveniles are out of the breeding-nest and no cannibalism has occured, the division of these juveniles at instar 2 with about 5 per Petri dish, should prevent cannibalism later. CONCLUSIONS Intraspecific predation in C. corticalis during two especially susceptible periods of develop- ment (mating and dispersal) involves limited risks of cannibalism which can be eliminated. Mating must be at 13°C. Males in the enclosures with females must be limited to 24 hours, and dispersing juveniles must have sufficient prey. Cannibalism should not, therefore, be an obstacle to the mass breeding of this species for biological control. Rates of intraspecific and interspecific preda- tion have often been considered very high in spiders. The main enemies of spiders are often other spiders (Bristowe, 1941; Foelix, 1982). Certain species partially practice araneophagy (e.g. Pardosa lugubris (Walck-enaer), Lycosa annulata Thorell), and a few make it their speciality (e.g. Mimetus, Ero, Portia) (Table 1). In fact, the species most studied for cannibalism are araneophagic in nature. In contrast, in other species, araneophagy appears to be almost non- existant (Table 2) eyen without prey (e.g. Anyphaena accentuata, C. corticalis, Diaea dor- sata, Philodromus cespitum) and it is absent in social spiders such as Mallos gregalis (Simon) (Jackson, 1979, 1980), Behaviour of a few spider species cannot be applied to all. The degree of araneophagy of a species must be based on only thatone. Therefore, the levels of intraspecific and interspecific predation amongst the more abun- dant species in agrosystems in which a spider is a possible biological contrel agent must be studied, A simple method has been finalised for spiders which do not spin a web (Mare, 1992). ACKNOWLEDGEMENTS Thanks to Didier Capdeville for his help in breeding the spectes studied. LITERATURE CITED AUSTIN, A.D. 1984. Life history of Clubiona rabusta L. Koch and related species (Araneae, Clubionidac) in South Australia. Journal of Arachnology 12: 87-104. BLANKE, R. 1972. Untersuchungen zur Okophysiologie und Okethologie yon Cyr- laphora citricola Forskal (Araneae, Araneidae} in Andalusien. Forma Function 5: 125-206, BRISTOWE, W-S. 1941. ‘The Comity of Spiders’, Vol, 2, (Ray Society: London). 1958. The Clubionoidea - Gnaphosidae, Clubionidac and Anyphaenidae. Pp. 116-132. In, Pe World of Spiders’. Ed, Collins (revised 1971}. CANARD, A. 1984. Contribution 4 la connaissance du développement, de l'ccologie, et de Vécophysiologie des Aranéides de landes ar- Moricaines. (Thése de Doctorat Etat, Rennes, 389pp + annexe). 1987. Analyse nouvelle du développement pos- tembryonnaire des araignées. Revue Arach- nologique 7: 91-128. 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Joumal of Zoology (London) 214: 227-238. JACKSON, R.R, & HALLAS,S.EA. L98&6a, Predatory versatility and intraspecific interactions of spar- tacine jumping spiders (Araneae; Salticidae): Brettus adonis, B, cingvlatus, Cyrba algerina, and Phacacius sp. mdet. New Zealand Journal of Zoology 13: 491-520. 1986b, Comparative biology of Portia africana, P. alhimana, P. Jimbriata, P. labiata, and P. shulizi. arancophagic, web-building jumping spiders (Araneae: Salticidae): atilisauon of webs, predatory versatility. and intraspecific interac tons. New Zealand Journal of Zoology 13: 423- A89, 1990, Evolutionary origins of displays used jn ag- gressive mimicry by Portia, a web-invading araneophagic jumping spider (Araneac: Sal- wala New Zealand Journal of Zoology 17. 7-23. JACKSON, R.R, & HARDING, D,P, 1982. In- waspecific interactions of Hoaloplurys sp. indet., a New Zealand jumping spider (Araneae, Sal- ticidae). New Zealand Journal of Zoology 9 487- 3510, JACKSON, R.R. & MACNAB, A.M. 1989. Display, mating, and predaniy behaviour of the jumping spider Plexippus paykullid (Araneac: Salticidac), New Zealand Journal of Zoology 16; 151-168. JACKSON, R.R. & POLLARD, S.D. 1990). In- raspecific inteructions and the fonction of courtship in mygalomorph spiders: a study of Porrhethele antipodiana (Araneae: Hexathelidae}. New Zealand Jounal of Zoology 17: 499-526. JACKSON, R.R. & POULSEN, B.A, 1990. Predatory versatility and intraspecific interactions of Supuri- na picta (Araneae: Clubionidae), New Zealand Journal of Zoology 17; 169-184, JACKSON, R.R. & ROWE, R.]. 1987. Web-invason and ey by New Zealand and Australian pholced spiders, New Zealand Joumal of Zoology 14: 139-140, JACKSON, R.R. & WHITEHOUSE, M.E.A. 1986. The biology of New Zealand and Queensland pirate spiders (Araneae, Mimetidae): aggressive mimicry, arancophagy and prey specialization. Jourmal of Zoology (London) (A), 210: 279-303. JACKSON, R.R. & WILCOX, R.S, 1990. Aggressive mimicry, prey-specific predatory behaviour ard predator-recognition in predator-prey intersections of Portia fimbriata and Euryatius sp. jJamping spiders from Queénskand. Behaviour Ecology and Sociobiology 26: 111-119. JARMAN, E.A,R. & JACKSON, R.R. 1985. The biwl- ogy of Taieria erebus (Araneae, Gnaphosiiac) an arancophagic spider from New Zealand: silk ililteation and predatory versatility, New Zealand Journal of Zoology 13: 321-541. KIRITANI, K,, KAWAHARA, S., SASABA, T. & NAKASUIL F, 1972. Quantitative evaluation of predation by spiders on the green rice leafhopper, Nephotettix cinticeps Uhler, by a sightcount methad. Researches on Population Ecology, Kyoto University 13: 187-200, KRAFFT, B,. HOREL, A. & JULITA, J.M, 1986, In- fluence of food supply on the duration of the gregarious phase of a matemal-social spider, Coeloves terrestris (Araneae, Agelenidae}, Jour- nal of Arachnology 14: 219-226. LECAILLON, A. 1905. Nouvelles recherches sur Ja biologie et la psychologie des Chiracanthior, Bul- Ietin del’ Association Philomatique d’ Alsace ct de Lorraine 7: 224-252. MANSOUR, F., ROSEN, D., SHULOY, A. & PLALIT, H.N. 1986. Evaluation of spiders as biological control agents of Spedeptera littoralis Jarvae on apple in Israél. Acta Oecologica, Oecologia Ap- plicata 1: 225-232. MARC, P. 1990a. Nycthermal activity rhythm of adult Clebiona carticalis (Walckenaer, 1802) (Arach- nida, Clubionidae). Acta Zoologica Fennica 1%): 279-285. 1990b, Données sur le peuplement d' Aranéides des troncs de ping. C.R. X11 Coll. Européen d'- Arachnologie, Paris (1); 255- 260, 1992. Intraspecific and interspecific interactions be- tween spiders from apple orchards, Comptes Rendu Xf Coll. Européen d’Ararachnologie, Neuchatel (Suisse). MARC, P. & CANARD, A. 1989. Les essais utilisation des Araignics en lutte biologique. 614 Bulletin de la Société Scientifique de Bretagne 14: 149-172. NENTWIG, W. 1985. Feeding ecology of the tropical spitting spider Scytodes longipes (Araneae, Scytodidae). Oecologia (Berlin) 65: 284-288, 1986. The prey of spiders, Pp. 249-264. In, W. Nentwig (ed.), ‘Ecophysiology of Spiders’. (Springer-Verlag: Berlin). POLLARD, S.D, & JACKSON, R.R. 1982. The biol- ogy of Clubiona cambridgei (Araneae: Clubionidae); intraspecific interactions. New Zealand Journal of Ecology 5: 44-50, RYPSTRA, A.L. 1983. The importance of food and space in limiting web-spider densities; a test using field enclosures. Oecologia (Berlin) 59: 312-316. 1986. High prey abundance and a reduction in can- nibalism: the first step to sociality in spiders (Arachnida). Journal of Arachnology 14: 193- 200 SCHAEFER, M. 1974. Experimentelle Untersuchun- MEMOIRS OF THE QUEENSLAND MUSEUM gen zur Bedeutung der interspezifischen Konkur- renz bei 3 Wolfspinnen-Arten (Araneae: Lycosidae) einer Salzweise. Zoologische Jahrbiicher, Systematik (Okologie), Geographie und Biologie 101: 213-235. TAHIRI, A., HOREL, A. & KRAFFT, B. 1989. Etude préliminaire sur les interactions mére-jeunes et jeunes-jeunes chez deux espéces d’Amaurobius (Araneae, Amaurobiidae). Revue Arachnologi- que 8: 115-128. TURNER, M. 1979. Diet and feeding phenology of the green lynx spider, Peucetia viridans (Araneae: Oxyopidae). Journal of Arachnology 7: 149-154, WOLF, A. 1990. The silken nest of the clubionid spiders Cheiracanthium pennyi and Cheiracanthium puncturium (Araneae, Clubionidae). Acta Zoologica Fennica 190: 397-404. YEARGAN, K.V. 1975. Prey and periodicity of Par- dosa ramulosa (McCook) in alfafa. Environmen- tal Entomology 4: 137-141. COMPARATIVE MORPHOLOGY OF THE SEXUALLY DIMORPHIC ORB-WEAVING SPIDER ARGIOPE BRUENNICHI (ARANEAE: ARANEIDAE) MONIKA C. MULLER anb WILFRIED WESTHEIDE Miller, M.C, and Westheide, W. 1993 11 11: Comparative morphology of the sexually dimorphic orb-weaving spider Argiope bruennichi (Araneae: Araneidae). Memoirs of the Queensland Museum 33(2): 615-620. Brisbane. ISSN 0079-8835. Although the web building spigots of the glandulae aggregatae and the glandulae flagellifor- mes are not functional in mature males, adult Argiope brwennichi and A. lobata males are- able to build webs. The structure of these webs is described, The aciniform spigots on the intermediate spinnerets of A, bruennichi males have degenerated to a great extent. Culture experiments withA, bruennichi enabled us to follow differences in the development of female and male morphology. The presence of the tubuliform spigots in the sixth instar suggests one possible evolutionary hypothesis concerning sexual dimorphism in spiders. Nach der Reifehiiutung sind die aggregaten und flagelliformen Spulen—welche als Triade die Pangfiden sezermieren—auf den hinteren Spinnwarzen der Miinnchen nur rudimentiir avs- gebildet. Trotz. dieser Redukhion spannen adulte Argiope bruennichi und A. lobata Mannchen Radnetze, deren Struklur beschricben wird. Auf den mittleren Spinnwarzen subadulter und adulter A. bruennichi Minnchen ist ein hoher Prozenisatz der aciniformen Spulen unvollstindig ausgebilder. Durch Aufzucht der Wespenspinne war cs méglich, morphologi- sche geschlechtsspezifische Unterschiede in der Postembryonalentwicklung festzustellen, Das friihe Auftreten der tubuliformenSpulen im weiblichen Spinnapparat kann als Argument fiir cine Hypothese zur Evolution des Sexualdimorphismus interpretiert werden. [)% Development, sexual size dimorphism, spinning apparatus, male orb-webs, tbulifarm spigot. Monika C. Miiller and Wilfried Westheide, Universitét Osnabriick, Fachbereich Bivlogie/Chemie, Spezielle Zoologic, D-49069, Osnabriick, Germany; 28 Octaber, 1992. Sexual dimorphism varies across taxa, but the question of whether highly dimorphic species occur as a result of selection for large female or small male size Temains controversial. Gerhardt (1924) observed that both car- nivorous feeding habits and cannibalism en- danger male spiders before, during and after copulation (Elgar and Nash, 1988). Darwin (1890) and Bristowe (1929) suggested that their small size protects the males from the females which do not recognize males of reduced size as prey. In contrast, Gerhardt (1924) and Vollrath (1980) areue that ‘the females have evolved to be larger, allowing greater egg production’ (YoUrath, 1980: 165). Morphological investigations of sexual size dimorphism are rare; for example Sekiguchi (1955a, b) compared the spinning apparatus jn male and female spiders. The present investiga- tion examines whether or not there are mor- phological data that could be used to assess these chfferent ideas, by analysing the spinning ap- paratus in different instars of Argiope brvennichi. MATERIALS AND METHODS Adult males and females of Arginpe braenniche (Scopoli, 1772) were collected from Dabas (Hun- gary), and subadult males and cocoons from Wit- tenberg-Lutherstadt (Germany}. Specimens of A. bruennichi were raised in- dividually from the third instar. Some individuals from each instar were fixed in Carnoy’s fluid immediately after moulting. The lengths and widths of the prosoma were measured. For SEM studies the spinning apparatus was removed and the spinnerets were dehydrated in ethanol and critica] point dned with carbon dioxide. After Sputtering with gold, they were analysed with a Cambridge Stereoscan 250. For light microscopy the spinnerets were separated into smaller pieces and embedded in Swann-fluid. Subadult males of A. bruennichi were kept in plexiglass frames from the penultimate stadium until they died. Early instars were fed with greenflies (Aphidina) and Drosophila melanogaster while older stages were provided with various insects captured in the field, RESULTS Apu Arciove Mates can Spin WES The posterior spimnerets of adult males are 616 MEMOIRS OF THE QUEENSLAND MUSEUM SEXUAL DIMORPHISM IN ARGIOPE BRUENNICHI equipped only with rudimentary projections of the triad spigots (Fig. 1). These aggregate and flagelliform spigots—which usually furnish the capture threads—obviously do not function. Nevertheless, adult males of A. bruennichi and A. lobata spun rudimentary orb-webs (Fig. 2). These webs were destroyed every day during our study and the spiders renewed them almost daily. Sub- adult males spun normal orb-webs with the typi- cal stabilimentum until the last moult. Webs spun after the terminal moult were smaller than sub- adult webs. They showed an irregular structure; but radia and a spiral were present. This spiral consisted of a few turns with remarkably increas- ing space outwards thus showing a closer resemblance to the auxiliary spiral than to the capture spiral. No droplets adhered to the spiral threads when the spiders were sprayed with water using an atomiser. They seemed to be thinner than capture threads and were not sticky. Prey thrown into the webs did not adhere to the spiral threads. A microscopical investigation revealed that their structure also strongly resembled auxiliary threads (Figs 5-7). The auxiliary nature of the web was confirmed by comparing the connection points of different types of threads with the radia (Figs 8-9). INTERMEDIATE SPINNERETS OF ADULT MALES The number of piriform and aciniform spigots for each sex were counted under the light micro- scope. There were fewer bases than apical parts of the aciniform spigots in the intermediate spin- nerets of males. SEM examinations showed that a surprisingly high number of apical parts were degenerated (Figs 3-4). Only 19.2% (6 in- dividuals) of the aciniform spigots on the inter- mediate spinnerets were fully developed. This degeneration was less in subadult males. POSTEMBRYONIC DEVELOPMENT OF Bopy SIZE The shape of the opisthosoma changed during the development of A. bruennichi. The spherical form changed into an elongated one, reaching the proportion of adult spiders at the sixth instar. This pattern is clearly shown by the length/width- quotient of the opisthosoma in each instar (see Table 1). The development of both prosoma and opisthosoma was nearly uniform for all in- dividuals until the sixth instar, although the inter- 617 i TI VI | VIE | Vi 13. #114 = |14 {16 [19 [18 [20 {19 [19 [s.p. |o.09 [o.os [oo4 [oo |- |-|-_fo.ra Jo.se | TABLE 1. Argiope bruennichi. Length/width- quotients and standard deviation of the opisthosoma for different instars (II- VIII) and adults (n = 62). vals between the moults varied (instar III to IV: 17-73 days; instar IV to V: 11-52 days). Follow- ing the sixth instar (when subadult males could be first determined) the sexes developed dif- ferently (Fig. 15). This pattern of development of sexual dimorphism is less apparent in the prosoma. PosTEMBRYONIC DEVELOPMENT OF THE SPINNING APPARATUS The development of the spinnerets was docu- mented by counting the piriform and aciniform spigots. None of these fusules was found in the second instar (Fig. 10). Six piriform (anterior spinnerets), two aciniform (intermediate spin- nerets) and three aciniform spigots (posterior spinnerets) were counted for third instar in- dividuals (Figs 11-13). The development of the spigot number was uniform until the sixth instar. From that stadium on, the sexes developed dif- ferently as shown for the aciniform spigots on the posterior spinnerets (Fig. 16). Although the anterior and intermediate spinnerets develop in the same way (Fig. 16), the differentiation of the sexes Is less obvious. Tubuliform spigots were also first observed in the sixth instar of female spiderlings (Fig. 14). DISCUSSION The degeneration of the triad spigots on male posterior spinnerets during the terminal moult was first described by Sekiguchi (1955b) and subsequently documented for other species. These morphological reductions in males were explained by changes in their behaviour: adult males cease spinning webs and instead search for females. Emerton (1878) and McCook (1890) mentioned that small webs were spun by Argiope aurantia males, but no information about the structure of these webs was provided. This study shows that A. bruennichi and A. lobata males are capable of spinning webs. The spiral threads of FIGS. 1-9. 1. Triad spigots at posterior spinneret of adult male. Apical parts of aggregate (ags) and flagelliform (fs) spigots missing, bases vestigal. 2. Orb-web of adult Argiope bruennichi male. 3. Intermediate spinneret of adult male. Many apical parts of aciniform spigots missing. 4. Detail of 3. 5-9. Different structures of male webs. 5: Capture thread (subadult male); 6: Auxilliary thread (subadult male); 7: Spiral thread (adult male); 8: Junction of a capture thread with a radia; 9: Junction of a spiral thread with a radia. 618 MEMOIRS OF THE QUEENSLAND MUSEUM FIGS 10-14. Developmental stages of spinning apparatus, 10: Second instar; anterior (A), intermediate (1) and posterior spinnerets (P) are undeveloped; 11-13: Third instar; 11; Anterior spinneret with six piriform (ps) and two ampullate (ams) spigots; 12: Intermediate spinneret with two aciniform (acs) and two ampullate (ams) spigots; 13: Posterior spinneret with three aciniform spigots (acs) and the triad (consisting of two aggregate (ags) and one flagelliform (fs) spigots; 14: Detail of posterior spinneret of @spiderling at sixth instar. Tubuliform spigot (ts) is clearly to differentiate from aciniform spigots (acs), Note arrangement of triad: aggregate (ags) and flagelliform (fs) spigots slay apart from each other, typical for subadults. these webs resemble auxiliary threads, and there- fore are not furnished by the triad glands which still exist immediately after the last moult (see Sekiguchi, 1955b). The auxiliary thread type was recognized because the threads were not covered with glue droplets, However, it is possible that these threads are not auxillaries: Vollrath and Edmonds (1989) found that the glue is soluble in SEXUAL DIMORPHISM IN ARGIOPE BRUENNICHI re a e \ E | = oe bed = 4 aT rd of 5 o--- E {aga - wv 2 = } a * S : 14 > A 1 o+ T + 7 r T ——— ph = ! M" Ul Vv y vi vil Wiehe aX 15 sumber of instars sou ! o 60 2 _— | ow | St Gy---2 3 ’ * H a BE ow 2 ; an ‘ 4a ag | ee Ta 8a ae | sa | oo “aL . a Ns 2° 2 ' ao t ' ae ro =p ' i] Nil VW y Mi vil Nt IX number of Inetara FIGS 15-16. Postembryonic development of Argiope bruennichi: 15: Opisthosoma length; 16: Number of aciniform spigots at posterior spinneret. water and Peters and Kovoor (1991) argue that the glue does not necessarily fall into droplets. It is not clear why adult males produce these rudimentary webs, but their poor design suggests that it is unlikely that they function to catch prey. That adult males rejected food offered with tweezers can support this assumption. The females in spider genera that exhibit ex- treme size dimorphism are usually hemisessile. Thus courtship and mating is achieved by male mobility. Male mobility is achieved by using bridging lines and ballooning (Peters, 1990). Mc- Cook (1890) described these balloon lines as consisting of quite a number of threads that remain separated from one another, which sug- gests that they are furnished by the aciniform spigots. The degeneration of these aciniform spigots on the intermediate spinnerets of adult Argiope bruennichi males may occur because the remaining spigots are sufficient to produce the balloon lines. Alternatively, these threads may originate from other spigots. If the aciniform oly spigots of the posterior spinnerets furnish the balloon lines, then their degeneration on the in- termediate spinnerets would not disadvantage the males. Since adult males do not depend on the additional function of the aciniform threads (in terms of prey wrapping) their degeneration may be interpreted as a morphological adaptation to an altered style of life. These results suggest that the development of sexual dimorphism takes place in the sixth instar. Townley et al. (1991) reported tubuliform spigots in Araneus cavaticus in the fourth instar, which is equivalent to the sixth instar of Argiope. Townley ef al, (199)) suggested that the tubuliform spigots are present that early in order to ‘stake out sites for the functioning spigots of mature females, because the tubuliform glands are poorly developed and do not serve any func- tion at that time’. This explanation seems unlikely because the spinnerets are reorganized and the number of fusules increases with each moult. In contrast, we consider the existence of the tubuliform spigots already at the sixth instar in female spiderlings to be an indication for the hypothesis that phylogenetically earlier females reached maturity at this developmental stage. In females the tubuliform spigots may indicate the penultimate stadium as do the swollen palpi in males. While the males become mature, females undergo another series of moults (3-4) to reach maturity. During their phylogenetic his- tory, the females in the subadult stage—more ex- actly in the penultimate stadium-undergo a prolongation of their development resulting in a larger body size, directly correlated with higher egg production, Therefore, sexual size dimor- phism may have evolved to produce larger females, a hypothesis as especially presented by Gerhardt (1924) and Vollrath (1980). ACKNOWLEDGEMENTS We wish to thank Dr. Peter Sacher (Witten- berg-Lutherstadt, Germany) for valuable discus- sions and for the Argiope material. LITERATURE CITED BRISTOWE, W.S. 1929. The mating habits of spiders, with special reference to the problems surround- ing sex dimorphism. Proceedings of the Zoologi- cal Society of London 21; 309-358, DARWIN, C, 1890. ‘Die Abstammung des Menschen und die geschlechtliche Zuchtwahl’. (Bd. I, E. Schweitzerbart’sche Verlagsbuchhandlung, Stut- tgart). 620 EMERTON, J.H. 1878. ‘The structure and habits of spiders’. (Salem). ELGAR, M.A. & NASH, D.R. 1988. Sexual can- nibalism in the garden spider Araneus diadematus. Animal Behaviour 36: 1511-7. GERHARDT, U,. 1924. Neve Studien zur Sexual- biologie und zur Bedeutung des sexuellen GréBendimorphismus der Spinnen. Zeitschrift fiir Morphologie und Okologie der Tiere 1: 507-538. MCCOOK, H.C. 1890. ‘American spiders and their spinning work’. vol. 2. (Philadelphia). PETERS, H.M. 1989. On the structure and glandular origin of bridging lines used by spiders for moving to distant places. Acta Zoologica Fennica 190: 309-314. PETERS, H.M. & KOVOOR, J. 1991. The silk-produc- ing system of Linyphia triangularis (Araneae, Linyphiidae) and some comparisons with Araneidae. Zoomorphology 111: 1-17. SEKIGUCHI, K. 1955a. Differences in the spinning MEMOIRS OF THE QUEENSLAND MUSEUM organs between male and female spiders. Science Reports of the Tokyo Kyoiku Daigaku University, Section Zoology 8: 23-32. 1955b. The spinning organs in sub-adult geometric spiders and their changes accompanying the last moulting. Science Reports of the Tokyo Kyoiku Daigaku University, Section Zoology 8: 33-40. TOWNLEY, M.A., HORNER, N.V., CHERIM, N.A., TUGMON, C.R., TILLINGHAST, E.K. 1991. Selected aspects of spinning apparatus develop- ment in Araneus cavaticus (Araneae, Araneidae). Journal of Morphology 208: 175-192. VOLLRATH, F. 1980, Why are some spider males small? A discussion including observations on Nephila clavipes. 8. Internationaler Arachnologen KongreB, Wien, 165-169. VOLLRATH, F. & EDMONDS, D.T. 1989. Modula- tion of the mechanical properties of spider silk by coating with water, Nature 340: 305-7. A METHOD TO DEVELOP AN ‘INDICATOR VALUE’ SYSTEM FOR SPIDERS USING CANONICAL CORRESPONDENCE ANALYSIS (CCA) RALPH PLATEN Platen, R. 1993 11 11: A method to develop an ‘indicator yalue* system for spiders using Canonical Correspondence Analysis (CCA), Memoirs of the Queensland Museum 33(2): 621-627, Brisbane, ISSN 0079-8835. Multivariate Canonical Correspondence Analysis (CCA) is used to derive ‘indicator values" for spiders, similar to those used for plants, The data set consists of activity abundance values of spiders, sampled by pitfall trapping in various habitat types (mites, woods, dry grassland) in the Berlin area. Light exposure, soil moisture and temperature were also measured at the sites. Species scores are plotted as a function of environmental factors within an ordination diagram. The method used to determine the indicator value from this ordination diagram is presented. The system of indicator values is regarded as a suitable method to evaluate sites and areas casily. Advantages and limitations are discussed. Mit Hilfe der multivariaten statistischen Methode Kanonische Korrespondenz. Analyse (CCA) werden Zeigerwerte fiir Webspinnen, dhnlich denen fiir Pflanzen ermiitell, Die Entwicklung dieses Zeigerwertsystems und dessen Anwendung wird im Prinzip beschrieben, Der verwendete Datensatz besteht aus Aktivititsabundanzwerten von Spinnen, die mil Bodenfallen in anterschiedlichen Biotoptypen (Mooren, Wildern und Trockenrasen) im Gebiet von Berlin gefangen wurden, Die an den Standorten gemessenen abiotischen Faktoren Licht, Temperatur und Bodenfeuchte werden mit in die CCA cinbezogen. An Hand von Beispiclen wird der Weg erliiuiert, Zeigerwerte aus Orclinationsdiagrammen zo ermitteln. Mit Hille einiger Arten werden Anwendungsbereich und Beschrankungen des Zeiger- werlsystems aufgezeigt und diskutiert. Das Zeigerwertsystem wird als eine brauchbare Methode betrachtet, um Standorte und Untersuchungsgebiete relativ leicht mit Hilfe der Spinnen zu bewerten. (Araneae, indicator value, multivariate analysis. Ralph Platen, Instinut fiir Bodenzoologie und Okologie, Freie Universitit Berlin, Tierzenweg 85-87, W-1000 Berlin-45, Germany; 12 January, 1993. Ecosystems. change under anthropogenic in- fluences faster than their structures and functions can be analysed, It is therefore difficult to make well-founded comments about their ability to withstand external pressure, or about possibilities for their protection or renaturalisation. The com- plex ecological questions this deficit poses will require field work involving as many environ- mental factors and groups of organisms as pos- sible. GOALS A first step is the description of the ecological behaviour of species in the field. A further step is lo derive evaluations for the sites. biotopes or areas of study from the ecological behaviour of the species. For example when establishing whether an area should be protected, tor purposes of planning and biotope-management as well as when studying the changes at the siles under anthropogenic influence, an efficient evaluation system which beyond that is casy to handle will he necessary. A number of evaluation systems have recently been developed, e.g. for soil organisms by Wodarz er al. (1992), for epigaeic predatory arthropexts (spiders and ground beetles) by Haenggi (1987) and Platen (1989. 1992), for spiders by Martin (1991) and for ground bectles by Mossakowski and Paje (1985), Some of these evaluation systems describe the ecological be- haviour of the species in the field very precisely (Martin, 1991), or allow a differentiated evalua- tion of sitse or areas of study (Mossakowski and Paje, 1985; Haenggi, 1987; Platen, 1959). Some evaluation systems, however, have the disad- vantage that lengthy calculations are necessary for synoptic evaluation for different sites or areas (Wodarz er al.. 1992; Haenggi, 1987). In other cases parameters are used in the calcblations which are not stable for time and/or locality, such as a low local abundance of a species, or the numbers of individuals of a species caught in a year (Mossakowski and Paje, 1985). The evalua- tion systems mentioned can also only be applied locally where, as a result of intensive field work, the ecological behaviour of species along abiotic gradients is known. A much simpler method would be the applica- tion of an indicator value system similar to thal for plants of Ellenberg et al. (1991). It would then no longer be necessary to redetermine and re- evaluate the ecological behaviour of a species for cach local investigation, since this would already be contained in the key values. Nor would the evaluation involve complicated calculations. My aim has been to develop just such an in- dicator yalue system for spiders, MATERIAL AND METHODS Data ‘The data consisted of the activity abundances of spider species. These were determined using ground traps in the Berlin area for open and wooded sites in moors, in various types of forest and for heathland and semi-dry and dry meadows. The investigation period was a full year in each case. Activity abundance is defined by Heydemann (1953) as the number of individuals, which has been trespassed a borderline (which is represented by the diameter of the pitfall trap) within a certain period of time. Parallel to the trap catches the following abiotic factors were also measured: The soil water content (measured as the per- centage by volume of water in the upper soil layer), the light exposure using the method described by Friend (1961), and the effective temperature after Pallmanon ef al (1940). The sites are described in detail in Platen (1989). GENERAL The activity abundance of the spider species and the measurements of the abiotic factors are analysed using Canonica] Correspondence Analysis (CCA; Jongman ef a/.. 1987), using the program CANOCO Version 3.10 (Braak, 1988, 1991), The results of this analysis are displayed as Ordination diagrams using CANODRAW (Smilauer, 1990). Before running CCA the spider data had been masked according to dominance in a formal way: species which did not have an activity abundance of atleast 1% at asite were removed [rom the data set. This meant that of the original 281 spider species only 111 remained for the further analysis. Furthermore a transformation of the raw data was carried out. Instead of the abundance values their square roots were used. MEMOIRS OF THE QUEENSLAND MUSEUM RESULTS OrpimaTion DiGRAMs The CCA results with abiotic factors light ex- posure and temperature, us well us soil water content, are shown graphically (Figs 1, 2). The honzontal axis corresponds to the first CCA axis and the vertical to the second CCA axis. The 111 species of spider are represented by an ‘x’, together with an abbreviation of the name as far as possible. Using CANOPLOT it was also pos- sible to determine the coortlinates and the name of a species which could not be presented unam- biguously tn the diagram. Initially the axes of the site factors light cx- posure and soil walter content are extended beyond the origin (Fig. 1). The factor along the ‘environmental axes’ increases in the direction of the arrow. The ongin marks the mean value for the entire data set. Species whose position lies between the arrowhead of an environmental axis and the origin have a larger weighted mean. Where the ongin is between the arrowhead and the position of the species, its weighted mein is smaller than the overall mean. For interpretation a perpendicular is projected for each species in tum onto the environmental axis according to their sequence (cf. Jongman er ai., 1987). Xys- ficus ninnii and Thanatus arenarius occupy the brightest sites, and Pardosa agrestis and Baryphyma pratense the warmest sites [Fig. 1). Species at extremes of the axes represent limits of the area for a two-factor system, and thus form the start and end points of the indicator valuc scale. The distance between these points is measured and divided into five equal parts. The species ure then noted for each class with the appropriate indicator value. The determination of indicator values for three factors requires at least two ordination diagrams. Initially an indicator value is assigned forall three individual factors, then for all combinations of two factors. The result always remained the same. For the representation of all three factors in an ordination diagram the class of a species can, however, change, in some cases considerably, since the relative spatial distances of the species in three-factor constellations cannot be repre- sented in a two-dimensional coordinate system withour distortion. For the determination of in- dicator values from the data of individual en- vironmental variables the solution (Figs 1 , 2 ) is an optimum, Moisture is strongly negative correlated with the Ist CCA-Axis (Inter-set correlation: -0,919) INDICATOR VALUES FROM CANONICAL CORRESPONDENCE ANALYSIS 623 2nd _ CCA-Axis Temperature Szet gore *Xyus ninn Par| agre Sar erat Tha ares nTfup diet | wn > ei elec eEur flav | duals ¥Tro Furi | Ist — CCA-AXis x “arsed Heb ciat™ D : 4 ‘Ba . Hai vigix Pir Tata > ee «gre uncs Leo tene bol fint SALI vidu “Dip pern FIG. 1. CCA ordination diagram with 111 spider aaa represented by an ‘x’ and environmental variables moisture and temperature represented by arrows. T ¢ part of the arrows to derive indicator values are devided into five parts (M1-MS5 and T1-T5 respectively). For farther explanation sec text. (Fig. 1) which means that the horizontal species distribution is best explained by light and less by temperature (Inter-set correlation with Ist CCA- Axis: 0.26, with 2nd CCA-Axis: 0.538). Hence, the vertical species distribution is best explained along the 2nd CCA-Axis, The Inter-set correlation between light and Ist CCA-Axis is 0,955 which means that the data set again is best explained by this abiotic factor. Temperature is strongly correlated with 2nd CCA-Axis (Inter-set correlation with Ist CCA- Axis: 0.0367, with 2nd CCA-Axis: 0.6177). INDICATOR VALUES (TABLE I) The last two columns contain details of the ecological type and habitat type in which the species predominantly occurs in the Berlin area (after Platen ef a/., 1991). The data are intended only to demonstrate the principle of this method. Tn view of the limited data set the indicator values cannot claim to be comprehensive or generally valid. Some examples will show the similarities and differences between the indicator values and other methods of determining ecological be- haviour. The distribution of Xysticus ninnii is centered exclusively on dry meadows. Fl, L5, and T4 reflect this ecological behaviour well. Diplocephalus permixtus: Occurring mostly in wet alder forest-habitats characterised by high soil water content, low light exposure and low temperatures. This is expressed with adequate precision by the indicator values F5, L1 and T2. Diplocephalus picinus: F2, L1 and T1 charac- terise its habitat preferences, namely shadowy sites with low pH in dry mixed forests. Pardosa agrestis: \n this case the indicator value does not reflect the ecological behaviour, as a result of the inadequacy of the data set. The species occurs mostly on arable farmland and 624 2nd CCA-Axis Temperature “Eri den Phiran eta? MEMOIRS OF THE QUEENSLAND MUSEUM *Tha aren Light «Twp diet >» Par palu -zel Pind is “Mei beat » ri cita kOe cone *Hah nous Ste hal eTri lute FIG, 2, CCA ordination diagram with 111 spider species represented by an ‘x’ and environmental variables light and temperature represented by arrows. The part of the arrows to derive indicator values are divided into five parts (LI-LS and T1-TS respectively). For further explanation see text. other open, rather dry habitat types (Platen et al., 1991). While T5 describes the behaviour in terms of temperature, the indicated soil water content (F5) is too high and the light exposure too low (L1). This is because in the data set it only oc- curred on one site (a former moor which was still wet in comparison to the sites on mineral soils), so that as an outsider it had an extreme position in the ordination diagram. The data set did not include arable farmland sites. COMMENTS This method is a relatively easy one to deter- mine indicator values for spiders and other soil arthropods (cf. Platen, 1992). Indicator values have the advantage that with only a few values the ecological behaviour of a species can be characterised. Mean indicator values can be calculated, and in the absence of the measurements or vegetation surveys they allow a rough quantitative assessment of environmental variables for a investigation site, habitat type or an area of study, The use of indicator values obviates the need for complicated calculations for the evaluation of siles, as required by some evaluation systems (Mossakowski and Paje, 1985; Haenggi, 1987; Platen, 1989). Some reservations concerning the applications of indicator values are necessary. As already em- phasised by Ellenberg et al. (1991), indicator values describe the ecological behaviour of species in a multiple system of biotic and abiotic factors, from which those chosen in this paper are regarded as the key abiotic factors for the spiders. They do not, however, describe their physiologi- cal optima. Indicator values for animals underlie more restrictions as those for plants because animals are mobile and often change their habitat for overwintering (Schaefer, 1976). Therefore in the strict sense they are valid only for Adults which does not change their habitat within their period of maturity. As juvenile animals were not in- cluded in the data set this holds true for this investigation. Indicator values should never be used in the same way aS measurements. They are ordinal, and are not suited for use in statistical (including multivariate) methods requiring higher scale data. The indicator values determined above are al- INDICATOR VALUES FROM CANONICAL CORRESPONDENCE ANALYSIS ways valid only for the data set used. Since they were limited to only a few types of biotope the results above can only be regarded as being a first approximation. The results of the analysis are greatly dependent on the type and number of habitats types and of the frequency with which various species occur there. The combination of a wel, light site (F5, LS) is not represented by an indicator value, although it is relevant for a num- ber of species (Drepanotylus uncatus, Antistea elegans) (Table 1). However, since almost 2/3 of the 30 sites investigated were wel, and most species occurred with almost the same frequency in wet habitats, these species grouped close to the ongin, Species which occur frequently, but only at one or two dry sites with very high light cx- posure are far from the ongin, so thal there is a higher differentiation of the axis over the bright Tange. A generally valid indicator value system would need to analyse all known spider species of Ger- many or Central Europe for all existing types of biotope (abiotic factor combinations) in one data set, from which the indicator values could then be derived. The scale could then be expanded, or other environmental factors, such as the biotope structure, could be included. A problem would be the large number of measurements required. A further problem is that the CCA only depicts species correctly in the ordination diagram if they have an unimodal response curve along a factor aradient (Jongman et al., 1987). By plotting the frequencies of species at all habitat types sorted according to the levels of a factor, it is possible to determine bi-modal, multi-modal or continuous responses, The coordinates of all the habitats where the species occurs with high frequency can be entered in the ordination diagram, making it possible to recognise a corresponding range of occurrence on the environmental axis. For this Species, as is the case with some plant species, an indifferent response to this factor for the species or to give a range of the indicator value (cf. Ellenberg et al., 1991) may be possible. ACKNOWLEDGEMENTS For ideas, criticism and discussion | would like tv thank Florian Bemmerlein-Lux, Nuremberg, Prof. Lasco Mucina, Vienna, and Prof. Gerd Wegmann, Berlin LITERATURE CITED BRAAK, C.J.F. TER 1988 CANDCO - 2 FORTRAN 625 program for canonical community ordination by [partial] [detrended| [canonical comespondence analysis, principal components analysis and redundancy analysis (Version 2.1)). Technical report LWA &8-02. Groep Landbouwwiskunde, Wageningen, 1990, Update notes. CANOCO Version 3.10. Manuscript, Agncultural Mathematics Group, Wageningen. ELLENBERG, H., WEBER. H1.E., DULL, R.. WIRTH, V., WERNER, W, & PAULISSEN, D, 1991. Zeigerwerte von Pflanzen in Mitteleuropa. Scripta Geobotanica XVI: 1-248, FRIEND, D.T.C. 1961. A simple method of measuring integrated light values in the field. Ecology 42: 577-580, HANGGI, A- 1987. Die Spinnenfauna der Feachtgebiecte des GroBen Mooses, Kt. Bern. 2. Die Beurteilung des Naturschutzwertes natur- maker Standore anhand der Spinnenfauna, Mit- teilungen der Naturforschenden Gesellschaft in Bem N.P_44; 157-185. HEYDEMANN, B. 1953. Agrardékologische Problematik, dargetan an Untersuchungen. tiber die Tierwelt der Bodenoberfliche der Kultor- felder. (Thesis, Kiel), 433 pp. JONGMAN, R.H,G., BRAAK, C.1.F, TER & TONG- EREN, O.F.R. (eds,), 1987, ‘Data analysis in com- munity and Jandscape ecology.” (Pudoc Books: Wageningen). MARTIN, D. 1991. Zur Autikologie der Spinnen (Arachnida: Araneae) |. Charakteristik der Habit- atausstattung und Praferenzverhalien epigdischer Spinnenarten. Arachnologia Mitteilungen 1:5-26, MOSSAKOWSKI, D. & PAJE, F. 1985. Ein Bewer- tungsverfahren von Raumeinheiten an Hand der Carabidenbestinde. Verhandlungen, Gesellschaft Okologie in Bremen 1983 13: 747-750. PALLMANN, H., EICHENBERGER, E. & HASEL- ER, A, 1940, Eine Methode der Temperaturmes- sung bei Gkologischen oder bodenkundlichen Untersuchungen. Berichte, Schweizerische Botanische Gesellschaft 50; 337-362. PLATEN, R. 1989. Struktur der Spinnen- und Laufktiferfauna (Arach.: Araneida, Col.: Carabidae) anthropoden beciiflubter Moorstan- dorte in Berlin (West); taxonomische, riiumliche und zeitliche Aspekte. (Thesis: Technische Universitit Berlin) 470 pp, PLATEN,, R., MORITZ, M. & BROEN, B.y. 1991. Liste der Webspinnen- und Weberknechtarten (Arach.; Araneida, Opilionida) des Berliner Raumes utd ihre Auswertung § fiir Naturschulzzwecke (Rote Lisie), Pp, 243-275, In A, Auhagen, R. Platen and H. Sukopp (eds). ‘Rote Listen der gefahrdeten Pflanzen und Tiere im Berlin’ (Landschafisentw.: Umweltforsch, S6). PLATEN, R. 1992. Die Entwicklung eines Zeiger- wertsystems fiir Laufkifer (Col.; Carabidae) mit Hilfe einer “Canonical Correspondeoce Analysis” 626 (CCA). Verhandlungen der Gesellschaft fiir Okologie 21: 321-326. SCHAEFER, M. 1976. Experimentelle Untersuchun- gen zum Jahreszyklus und zur Uberwinterung von Spinnen (Araneida). Zoologische Jahrbiicher, Systematik (Okologie), Geographie und Biologie 103: 127-289. MEMOIRS OF THE QUEENSLAND MUSEUM SMILAUER, P. 1990. CANODRAW. A companion program to CANOCO for publication-quality graphical output. (Ithaca). WODARZ, E., AESCHT, E. & FOISSNER, W. 1992. Der Bodenbiologische Index (BI) - ein quantita- tives MaB fiir die Bodenqualitat. Verhandlungen der Gesellschaft fiir Okologie 21: (in press). TABLE 1. Indicator values for soil water content (F), light (L), temperature (T) of 111 common spider species of varying types of habitat. ET=Ecological type: h = hygrophilic, (h) = weakly hygrophilic, x=xerophilic, (x)=weakly xerophilic, eu= euryoecious open-space dwellers, w=forest type, (w) = also in open spaces, hw=sparse forest species, (h)w=inhabits mesophilic deciduous forests, (x)w=inhabits forest on acid soil, h(w)=depending on type of preferred habitat: inhabits unwooded wet habitats or sparse forest. - = no preferred habitats. Family (C): Ag, Agelenidae; Dy, Dysderidae; Gn, Gnaphosidae: Ha, Hahniidae; Li, Linyphiidae; Lc, Liocranidae; Ly, Lycosidae; Ph, Philodromidae; Pi, Pisauridae; Sa, Salticidae; Te, Tetragnathidae; Tr, Theridiidae; Tm, Thomisidae; Zo, Zoridae. SPECIES F |L {|T JET Gg SPECIES F Cc Wet Forests W. cucullata (C.L. Koch) 2 i Pachygnatha listeri Sundevall 5 1 3. [hw Te W. dysderoides (Wider) 4 Li i 4 1 3 i W. monoceros (Wider) 2 (x)w {Li B. nigrinus (Westring) Sil 3 Euryopis flavomaculata (C.L. Koch) |4 iplocephalus permixtus (O.P.C.) 5 {1 [2 Trochosa terricola Thorell 3 |eo@m) |Ly 4 {1 2 Xerolycosa nemoralis (Westring) 2 [@dcw) [Ly | Gonatium rubellum (Blackwall) 3 1 |2 Cicurina cicur (Fabricius) 4 Porrhomma pygmaeum (Blackwall) |4_ |1__|3 Agroeca brunnea (Blackwall) 4 Walckenaeria atrotibialis (O.P.C.) 4 1 2 Haplodrassus soerenseni (Strand) 1 Pirata hygrophilus (Thorell) Sj) {3 [how [Ly Zelotes subterraneus (C.L. Koch) 3 Deciduous forests Ozyptila praticola (C.L. Koch) 2 Centromerus sylvaticus (Blackwall) [4 |1 |2 |(h)w [Li Waterside sites Ceratinella brevis (Wider) 3 |) [2 [tw fLi Gnathonarium dentatum (Wider) 5 |1 |4 |h Li Diplocephalus latifrons (O.P.C.) 3 41 ]2) |(w Li Moors Gongylidium rufipes (Sundevall) 3. |] |2 | (hy) [Li Agyneta cauta (O.P.C.) 5 jl h(w) {Li Lepthyphantes pallidus (O.P.C.) 2 |) [2 |ayw [Li_| | Diplocephalus dentatus Tullgren h(w) [Li L. tenebricola (Wider) 4 |1 j2) |(h)w [Li Drepanotylus uncatus (O.P.C.) h Li L. zimmermanni Bertkan 2 |) |) |w {Li Erigonella ignobilis (O.P.C.) 3 th Li Microneta viaria (Blackwall) 3 {1 {2 |(h)w {Li Lepthyphantes mengei Kulezynski 5 fl h(w) {Li Neriene clathrata (Sundevall) 4 [1 {3 |a@yw [Li | | Zophomma punctatum (Blackwall) h Li Pardosa lugubris (Walckenaer) 4 1 |3) |(qw IL Notioscopus sarcinatus (O.P.C.) h Li Dry mixed forests Oedothorax gibbosus (Blackwall) 5 |1 |4 |h Li Harpactea rubicunda (C.L, Koch) 1 1 1 |@w_ |[D Silometopus elegans (O.P.C.) 5 1 {5 {h Li Abacoproeces saltuum (L. Koch) 2 1 1 (x)w [Li Tallusia experta (O.P.C.) 5 1 4 ) Li Centromerita concinna (Thorell) 2 43 {2 ={(x)(w) [Li | Walckenaeriaalticeps Blackwall [5 [1 [4 [nw) [Li | Centromerus pabulator (O.P.C.) 3 1 {2 {(x)w) [Li W. kochi (O,P.C.) 1 4 {h Li Diplocephalus picinus (Blackwall) 2 {1 1 fw [Li W. nudipalpis (Westring) 5 |1 |4 Jh Li Gonatium rubens (Blackwall) 2 {1 [1 [oow [Li W. vigilax (Blackwall) 5 h Li i er angulipalpis 2 11 |) |oow {Li Arctosa leopardus (Sundevall) 5 |1 |3 |h Ly Lepthyphantes flavipes (Blackwall) 2 1 1 (x)w {Li |Ebierofyoose ewbrofascinta (Obert) 13 ! th Ly Macrargus rufus (Wider) 4 1 |2 |@)w_ {Li Fardosa pullata (Clerc) 2 113th 2 cra : P. latitans (Blackwall) 5 Minyriolus pusillus (Wider) 2 {i 1 {@w [Li P. piraticus (Clerck) 5 li [3 |n [ty | Panamomo, ihert ei Simon 1) 1 |@w us P. piscatorius (Clerck) 5 li 13 Ih Ly Tapinocyba eeseae (L, Koch) 2 jl [2 |QOw x P. tenuitarsic Sirion 5 | 1 la Ih L Walckenaeria acuminata Blackwall |4 1 3) |(@)w {Li Trochosa spinipalpis (F.O.P.C.) 5 1 3 Ihw) [Lb INDICATOR VALUES FROM CANONICAL CORRESPONDENCE ANALYSIS 627 TABLE 1. continued SPECIES SPECIES ET |c Dolomedes fimbriatus (Clerck) Tegenaria agrestis (Walckenaer) [4 fi [a | & Ag Antistea elegans (Blackwall) Heathland Tricca lutetiana (Simon) 1 3.12 |) L Ba Li Zelotes latreillei (Simon) 2 [a fa [ow [Gn Dry grassland [Pachygnatha degeeriSundevall___|2_|2_| Adit ov, ——__ [Meionetabeata(OPc) __———{a_|4 [3 |x [ui | g 2 ane 1 Troxochrus scabriculus (Westring) 2 igi LPC. 1 1 i " 1 Li Li yphochrestus digitatus (O.P.C.) Steatoda phalerata (Panzer) ~ | |x [LH Lx 2 4 A mn) 1 T 5 | Pelecopsis mengei (Simon) 3 Pardosa palustris (Linné) 4 |1 _ prativaga (L. Koch) a | i 4 A 1 5 4 5 4 5 5 o ij | i | Hehe Oecdothorax fuscus (Blackwall) 4 | eu Li | . | l4_| fal ~ Hahnia nava (Blackwall) ] Agroeca proxima (O.P.C.) 4 Zelotes electus (C.L. Koch) ] = ~ .o Li [Tr L L L Ha [Le _| Gn ~ ) 5 Pocadicnemis pumila (Blackwall) |4_| 4 i 1 Stemonyphantes lineatus (Linné) i i i 1 Trochosa ruricola (De Geer) S X. ninnii Thorell 1 Arable fields Aelurillus v-insignitus (Clerck) 1 Bathyphantes gracilis (Blackwall) [4 i_| | Phlegra fasciata (Hahn) 1 3 as] is Ei ~ |x |x TK Lx Erigone atra (Blackwall) i No obvious habitat preferences E. dentipalpis (Wider) la | i Cnephalocotes obscurus (Blackwall) Pardosa agrestis (Westring) Zora spinimana (Sundevall) 4 1 w _ w fw Bade Q =) PIE] [ele |e o i] THE SPIDERS OF THE HIGH-ALTITUDE MEADOWS OF MONT NIMBA (WEST AFRICA): A PRELIMINARY REPORT C. ROLLARD Rollard, C. 1993 11 11: The spiders of the high-altitude meadows of Mont Nimba (West Africa): a preliminary report. Memoirs of the Queensland Museum 33(2): 629-634. Brisbane. ISSN 0079-8835, Spiders are abundant in the high-altitude meadows of the Nimba mountains, in Guinea, Collections have been carried out in this ecosystem where grass ground cover is dominant: this preliminary study at the family level concerns specimens collected in March 1991. It already gives some data on the localisation of the spiders. More than 20 families are represented along the mountain tops. A provisional list of these spiders has been drawn up. Most specimens were Araneidae, Gnaphosidae, Hersiliidae, or Salticidae. Their distribution in the herbaceous stratum as well as along an altitude gradient between 800-1700m is being analysed. Les araignées sont abondantes dans les prairies de haute altitude des Monts Nimba, en Guinée. Des récoltes ont été effectuées dans cet écosystéme od la couverture herbacée est dominante, Cette étude préliminaire au niveau des familles concerne les spécimens collectés en mars 1991. Elle apporte déja quelques éléments sur la localisation des araignées. Plus de 20 familles sont représentées sur ces sommets et une liste provisoire en a été établie. La plupart de ces araignées sont des Araneidae, des Gnaphosidae, des Hersiliidae ou des Salticidae. Leur distribution est analysée dans la strate herbacée ansi que selon un gradient altitudinal entre 800 et 1700m. (Spiders, biogeography, Africa, montane. Christine Rollard, Museum National d'Histoire Naturelle, Laboratoire de Zoologie (Arthropodes), 61 rue de Buffon, 75005 Paris, France; 14 January, 1993. The Mont Nimba biosphere reserve, located in West Africa, is the subject of a multidisciplinary study as part of a UNESCO pilot project. These mountains have been classified as an Integral Natural Reserve since 1944. Over the past 50 years, many more animals have been collected during several scientific expeditions directed by Professor Maxime Lamotte (Lamotte, 1943). Many papers have been published on the Nimba mountain range. However works on the spider fauna are non- existent. Hence the organization of the spider populations are still little known. Especially in this tropical region, no work deals with the ecology of spiders except for the research initiatives in the Ivory Coast, in the savanna of Lamto (Lamotte, 1943, 1967; Blandin, 1974; Blandin and Célérier, 1981). With this subject of research in mind, another field trip was made to Guinea in March 1991. The new collection of spiders made there compli- ments those of Mr Lamotte and his associates. This abundant material is in the process of being classified. An attempt is being made to describe the structure and function of the spider com- munity in this tropical ecosystem. The programme focuses on the spiders of the high-altitude meadow, relatively less-frequently collected than those of the savanna or the head of ravines (Lamotte, 1958). This environment is characterized by the strong contrast between the dry and rainy seasons. It presents a characteristic fauna with several endemic species. In this paper, preliminary data dealing with the localisation of the different families of spiders collected in March 199] are presented. The over- all study will lead to a more detailed inventory of the spiders along the mountain ridges, as well as a better knowledge of their distribution with al- titude and the relative abundance of the different species. ENVIRONMENT AND CLIMATE Mont Nimba is situated in High Guinea, near the borders of Liberia and the Ivory Coast (Fig. 1). Itextends from SW to NE for about 30 km into guinean territory. All the crests stand over 1000m. The mountainside is steep and notched by valleys with sheer slopes. No trees or shrubs are present on the crests. Only some small trees of the inferior savanna grow at lower altitude on the slopes (Schnell, 1966). Above 900-1000m, the forest is confined particularly to the ravines. The mountain range is covered by herbaceous plants with a grassland structure. The term of montane or sub-montane has been given to this 630 COTE D'IVOIRE 3 out & evan WJ jane 2 tenon ME iar an eu mm Limmiie da be repmtee maturetin Q FIG. 1. Map of Mont Nimba, West Afnea. Situation of the various sample zones along the Mont Nimbacrest. crest yegetation (Schnell, 1987). In this type of meadow, located in the guinean part of Nimba, the low (about 20-30cm or less) graminaceous species Loudetia kagerensis is abundant and con- stant. This grass forms a predominant group as- sociated with other tall or short species, varying from Site to site, Mont Nimba receives abundant rainfall and a dry season not exceeding three and a half months. Generally, high-altitude meadows are often covered in fog during the rainy season, from May to November. Precipitation is fine and stable. During the other periods of the year, clouds scale the slopes and progressively cover the crest. Thus the humidity, which is closely bound to the de- eree of precipitation and nebulosity, varies with altitude and also along the crest. For example, the crest of Nion, spreading upwards to Mont R. Molard in the NE, is wetter than either Mont P. Richaud or the region of Sempéré (Leclere et al., 1955). Nevertheless, seasonal variations do exist. In the meadow, this factor does not seem to be very important to the ecological cycle of the fauna, The spiders listed here were collected in March 1991], during the transition period just before the rainy season. Sudden storms or regular strong precipitations occur in the late afternoon from April onwards. MEMOIRS OF THE QUEENSLAND MUSEUM RELATIVE FREQUENCY 0 20 40 60 BO Agelenidee A4reneidee Clubionidae Corinnidae Cienidae Heteropodides Gnaphosidee Hersilidae Linyphiidae Liocranidee Lycasidae Oxyopidee Piseuridee Salticides ‘Scytodidee Selenopidee Siceriidee Tetragnathidae Theridiides Thomisidae Zodariides a“ in = 394) FIG. 2. Total no. spiders taken during March 1991. METHODS Up until now, the high-altitude meadows of Mont Nimba have rarely been sampled. The present study lasted 20 days (8-27 March) with only 14 days of sampling. The first phase con- sisted in obtaining an overall idea of the spider communities oyer the whole crest. The collecting program was prepared as follows: 4 days in Sempéré, Grands Rochers; 4 days on the Nion crest, 2 days in Grands Rochers. R. Mollard; 3 days on Mont Leclerc and 1 day in Ziela, P-. Richaud. No strictly quantitative sampling methods were used, Several gathering squares (1m x 1m) were made but the results are insufficient. In addition, these quadrats have not been well materialized because the transport of materials was not easy. Only the sizes were marked by various elements found on the ground. Furthermore, this type of analysis is rare in these environments. Some in- formation on the vertical distribution of the spiders was obtained by the use of beating and ground sweeping methods. A few specimens found on the high sections of the grass were captured, but this 1s certainly not a representative SPIDERS OF MONT NIMBA \ \ | \ < rt stems and Oxyopidae Agelenidae Corinnidae Clubionidae Cranidae Linyphiidae 5 ae ) if FIG. 3. Distribution of families in epigean environ- ment, sample of the spider fauna of the herbaceous stratum. So, in the low herbaceous stratum, samples were made by visual searching in vegetation and under stones, using forceps and pooters. Collect- ing was only carried out during the daytime and was therefore not exhaustive. The time spent on Mont Nimba was rather short: the researchers stopped collecting at the end of an hour at each site. A mean of 40 individuals was collected perday, by one to three collectors depending on the days and the availability of the expedition members. RESULTS FAmILies IDENTIFIED For each sample, the spiders were sorted and enumerated by family. Young and adult spiders were counted together. Immature spiders repre- sent about 54% of all specimens found. Mygalomorphs were collected, but not in great numbers: 0.5% (2/435). For the moment, the in- ventory of this suborder has not been established at the family level. Similarly, about 9% (39/435) of the collection is still at the level of indeter- minate araneomorph. Therefore, we are only able. to present results of the determinate araneomorph families, Which correspond to 394 specimens. The names used follow Brignoli (1983) and Plat- nick (1989), At least 21 families have been recorded along Pisaundae Sahicidae Sicariidae Thormsidae / Araneidae Salticidae Hersilidae Selanonidae thi uppey Telragnathidae part of Thomisidae leaves Liocranidae stem base Wen ey clump Lycosidae Salticidae heart * _ Theritidae | f, | HA Zodanidae ; an i a superficial soil LI ot 2 c a ,y ~ this crest, of the roughly 100 families known worldwide (Table 1). This relatively high number provides a good idea of the diversity of this en- vironment. The high-altitude meadow-like plateau savanna characterized by the grass species Loudetia, is usually considered to be one of the poorest habitats. However, this type of environment clearly possesses an important yariety of spiders. Furthermore, the relative frequencies of these spiders gives another indication of their diversity (Fig. 2). The physionomy of the: araneological community is characterized by the predominance of Araneidac which represent around 21% of determined spider families. Four other families were cormmon: Gnaphosidae (57/394), Her- siliidae (59/394), Salticidae (46/394) and Thomisidae (35/394). We note that these spiders are generally large and therefore easier to find. The same observation can be applied to other families which are more easily collected, espe- cially for a certain size. However, the fewer Clubionidae, Lycosidae, Oxyopidae, Pisauridae, Selenopidae and Tetragnathidae in the collec- tions could indicate that they are-less abundant in the meadow during this period of the year. The specimens belonging to most other families. are generally small and consequently poorly col- lected. In addition, Liocranidae and Zodariidae are active and move quickly on the soil, so they frequently evaded capture. VERTICAL STRUCTURE OF THE SPIDER COMMUNITY The quality of 3 sampling must take into con- 632 Hersiliidae Linyphiidae Liocranidae Lycosidac Oxyopidae Pisauridae Salticidae Agelenidae Araneidae Clubionidae Corinnidae Scytodidae Selenopidae Sicunidae Terragnathidae Theridiidae Thomisidae Zodariidae Ctenidae Heteropodidac Gnaphosidae TABLE 1, List of spider families on Mont Nimba sideration the biology and the size of the spiders. All families are represented, in spite of the small number of specimens, Around two-thirds of these families frequent the herbaceous stratum and most are diumal (Fig. 3). On the upper part of the stems and leaves of plants, the spider community is composed of eight families of which the Araneidae, Tetrag- nathidae, Hersiliidae and Thomisidae are the most common, The former two build their webs about 20 cm above the soil, Of all Araneidae, Oxyopidae and Salticidae, 25, 2 and | specimens respectively were collected by beating and sweeping of the ground. Ten families are present at the base of the stems or in the center of the clumps, Clubionidae being the most abundant. The clubionids are noctumal hunters and easily found in nests among the vegetation. Five families occur in the superficial soi! layer. The Lycosidae constitute most of the collections. Gnaphosidae are mostly nocturnal hunters found in nests among stones. Scytodidae are also found nocturnally active around stones. Thus, each level of this epigean environment seems to possess its own spidercommunity, char- acterized by its family composition. Neverthe- less, some of them such as the Salticidae, Thomisidae and Oxyopidae are present at all levels of the vegetation and the soil surface. Only analysis at the species level will permit the clarification of the distribution of the spiders in each stratum. ALTITUDINAL DisTRIBUTION The spiders were collected along the crest, mainly situated above an altitude of 1200m. The Tesulls are presented by altitudinal classes of 200m, principally because of the small numbers of spiders, and the vartous sampling zones are indicated in Fig, 1. An overall view indicates that some Families appear to be better represented at the highest altitudes, from 1200m to around 1700m (Table 2). The numbers of Gnaphosidae and Clubionidae regularly increase. Most other families did not MEMOIRS OF THE QUEENSLAND MUSEUM AUTH Quy ago 1960 eon Ovyopldae Trendidaa Litypfndae Sicariidée Selenopidae Ctenidae Liocranidae Agelenidse Corinmidae Tetregnathidge Gnaphosidas Ghubjonidae Bodaridae Arsnedae Saljiomde Hersillidae Thomisicae Lycositae Seyiogidaa Heleropocidae Pisauridae TOTAL NJNEER 25 5 s02 a7 155 OF SPECIMENS NUMBER OF 8 6 tm!) 3 io FAMILIES TABLE 2, Altitudinal distribution of spider families in meadow of Mont Nimba. provide many specimens, with the exception of Tetragnathidac. These spiders are perhaps rare or difficult to observe, but itis all the more interest- ing to note that their distribution is limited to a certain altitude. In the same way, Eusparassidae and Pisauridae are found only up to 1200m, in low vegetation. The lack of data, between 1000 and {200m altitude, for the Araneidae and Her- siliidae is probably due to sampling problems. Spiders of these families as well as the Salticidae, ‘Thomisidae and Lycosidae, are certainly present at the different altitudes, and it is likely that the same is the case for the Zodariidae, The family diversity seems to increase slightly with altitude. The collections made on slopes from 800m upwards concentrated particularly on Mont Leclerc (Table 3). Here too, we note the diversity of the spider fauna, with 14 families present of the 21 listed for Mont Nimba. The same families are found at the highest altitudes, Only Zodariidae and Clubionidae are not encountered below 1400m. Salticidae, Hersiliidae, Thomisidae and Lycosidae can be found from 800 to 1600m. We also compared the spider families found at three points along the crest: P. Richaud, Grands Rochers and Nion crest, between 1200 to 1600- SPIDERS OF MONT NIMBA 63 ALTITUDE (my Sicariidae Ctenidae Liocranidae Glubionidas Zadarjidae Graphasidae Araneidae Salticidae Hersiliidae Thamisidae Lycosidae Heteropodidae Pisauridae Scyiodidae TOTAL NUMBER 25 7 11 60 OF SPECIMENS NUMBER OF 8 4 5 WwW FAMILIES. TABLE3, Altitudinal distribution of spider families on Mont Leclerc. 1700m altitude (Table 4). Seven families are present on the Nion crest, clearly a lower diver- sity than on P. Richaud with eleven families. Six families were observed at all three places. Only Tetragnathidae were found south of the crest. This place seems to be more humid than the others at different periods of the year. The spiders found there are generally hygrophilous species. For the moment, we cannot provide definitive results on the ecological requirements of the ALTITUDE (m) ta families present only on P. Richaud and Grands Rochers. However, more precise information, at the species level will, hopefully, be available in the future. COMMENTS Spiders occupy an important place among the invertebrate fauna of Mont Nimba. They are rep- resented by about twenty families which is a relatively Jarge number for this type of highland meadow. This study is only a first approach; the diversity of the spider community according to stratum and altitudinal level will certainly prove to be rewarding, both quantitatively and qualita- tively, with the determination of species. Publi- cation of the final results will probably be delayed because of taxonomic difficulties. Nevertheless, this study already gives some results at the family level. Prudence in the inter- pretation of these results is necessary, because the families do not always form homogenous ecological units. The sampling methods used must also be taken into consideration. In the tables and figures, we see that the distributions found are dependent on the collecting effort. In this study we used mostly visual-hunting, with no collecting at night. So we only have a partial sample of the spider families, mainly repre- senting those with diumal activities. As yet, pit- fall] traps have not been used to intercept nocturnal spiders. Nevertheless, an estimation of the spiders present along the Mont Nimba crest and their spatial distribution has been made. We observe several components of this spider ALTITUDE 4m) ALTITUDE im } Oxyopideé yaaa soo Scytadidae 4200 yaaa iéon 7800 Gnaphosidar Einypniitas i Grsphosidae alstanis Selenopidae [ 1 | F4 rill sayfa Granhoodae [3 | aa awace Salticdae Glanicntd | Thomisidae Hersillidae ‘soiree Lycosidde Aoelenidae Araneitee Aranoidae Cormnidae Balipe Rs — Sallicidae Olubronidae weteioyte 7 st Tetragnathidae Téasheilpe Thomisidée Lyeasnise Lycosicae [ 2 | TOTAL NUMBER 42 1 so OF SPECIMENS TOTAL NUMBER 35 TOTAL NUMBER OF SFEOMENS OF SPECMENS NE TABLE 4. Altitudinal distribution of spider families along Nimba crest, from SW to NE: (a) Pierré Richaud; (b) Grands Rochers; (c) Nion crest before Richard-Molard, ai4 community, not forgetting the movements of wandering spiders. There are groups on the soil surface principally characterized by Lycosidae and Salticidae; three other families, Liocranidae, Zodariidae and Theridiidae exist in smaller num- bers, Groups in the lower part of the vegetation includes ten families, the most with few repre- sentatives; Clubionidae, Thomisidae and Sal- ticidae exist in great numbers. A last group exist of the upper part of the herbaceous stratum where Araneidae, Hersiliidae and Tetragnathidae are found in a great numbers; the five other families are less well represented. The comparison between the northern and southern parts of the crest indicates a possible tendency of one family (Tetragnathidae) to prefer greater humidity. The altitudinal distribution shows that some families, such as Araneidae, Salticidae, Hersiliidae, Thomisidae and Lycosidae, are present from 800 to 1752m. On the contrary, other families are preferentially localised at the highest or lowest altitudes. The spider families found between the altitudes 800 and 1000m, can be considered as being roughly comparable with those present tn typical savanna with Loudetia. In this environment, there are a great number of spider families (Gillon and Gil- lon, 1974). More data will be required to confirm these tendencies, as well as their presence on the slopes according to a greater altitudinal gradient and along the whole of the Mont Nimba crest. In addition, some comparisons among sites, includ- ing absence of families, might be artefacts, due to relative rareness of representatives. The study of all spiders collected during the previous expeditions directed by Prof. Lamotte will certainly provide supplementary elements to the various points mentioned in this paper- It will be necessary to characterize, with more precision, the araneological fauna of Mont Nimba. Blandin and Célérier (1981) already noted the misreading of this fauna in West Africa. In addition the well-collected environments are essentially savanna rather than high-altitude meadow.. MEMOIRS OF THE QUEENSLAND MUSEUM ACKNOWLEDGEMENTS I thank Professor M, Lamotte for allowing me to participate in this project, for providing me with the opportunity of undertaking the mission im Guinea, and for all his advice; Denise Palezewski and Mark Judson for reviewing the manuscript. LITERATURE CITED BLANDIN. P, 1974. Les peuplements d’ Araignées de Ja savane de Lamto. Bulletin de liaison des Cher- cheurs de Lamto 3: 107- 135. BLANDIN, P, & CELERIER M.L. 1981. Les Araignées des savanes de Lamto (Céte d'Ivoire). Publication Laboratoire de Zoologie, Ecole Nor- male Supérieure, 21,2 fasc., 586 pp. BRIGNOLI, P. 1983. ‘A catalogue of the Araneae described between 1940 and 1981". (Manchester University Press: Manchester). GILLON, D. & GILLON, Y. 1974. Comparaison du peuplement d'invertébrés de deux milieux herbacés ouest-africains: Sahel et savane préforestiére. La Terre et la Vie, 28: 429- 474. LAMOTTE, M_. 1943. Premier apercu sur la faune du ar Faculté des Sciences Universitaires, Paris, n,845, 1958. Le cycle écologique de la savane d' altitude du Mont Nimba (Guinée). Annales de Ja Société Royale de Zoologie de Belgique 89: 119-150. 1967. Recherches écologiques dans la savane de Lamto (Céte d'Ivoire) : présentation du milieu et du programme de travail. La Terre et la Vie 21: 197-215, LECLERC, J.C., RICHARD-MOLARD, J., LAMOTTE, M., ROUGERIE, G. & PORTERES, R. 1955. La chaine du Nimba. Essai géographique. Mémoire de l'l.F.A.N., 43,270 pp. PLATNICK, N.J. 1989. ‘Advances in Spider Taxonomy 1981-1987". (Manchester University Press: Manchester). SCHNELL, R. 1966. Guinée. Acta Phytogeographica Suecica 54; 69- 72. 1947. Les formations herbeuses montagnardes des monts Nimba (Ouest africain). Bulletin du Museum National d'histoire naturelle, Paris, 4, sér. 9(2): 137-151. VISUALLY MEDIATED RESPONSES IN THE LYCOSID SPIDER RABIDOSA RABIDA: THE ROLES OF DIFFERENT PAIRS OF EYES 1.8. ROVNER Rovner, J.S. 1993 11 11: Visually mediated responses in the lycosid spider Rabidasa rabida: the roles of different pairs of eyes. Memoirs of the Queensland Museum 33(2):635-638. Brisbane. ISSN 0079-8835. Video images of conspecifics were presented to Rabidosa rabida (Walckenaer) (Araneue: Lycosidae) to study the roles of different pairs of eyes ina wolf spider. Four groups of spiders had one pair of eyes occluded, and four had all but one pair occluded. Various control groups were also tested. The PLE were essential for sizeable orientation turns of up to about 160°, The PME served for rapid, long distance approaches toward the stimulus; they also initiated orientation turns of up to about 50°. If close to the stimulus, the ALE initiated small turns of up to about 20° and mediated small approaches, The AME did not mediate any responses. Courtship could be triggered in males via the PLE or the PME. In females, only the PME mediated receptive display responses to temporally patterned leg 1 movements seen in anterior or lateral views of a courting male. DAraneae, Lycosidae, eyes, vision, Ccommanica- fion, Jerome 8. Rovner, Department ef Biological Sciences, Irvine Hall, Ohia University, Athens, Ohio 45701, U.S.A,; 3 July, 1992, Very little behavioural research has been car- ried out on vision in lycosid spiders, compared to the extensive studies on salticid spiders (reviewed in Forster, 1985). In lycosid spiders, occlusion of the eyes has been used to test for differences in the roles of the main ys, secondary eyes (Homann, 1931) as well as the anterior vs. posterior eyes (Acosta ef al., 1982); however, the results of both of these studies were confounded by the lack of controls for vibratory stimuli. The only successful behavioural investigation of the role of particular eyes in lycosids (Magni et al., 1964) demonstrated the importance of the AME in astronomical orientation and was ac- complished by covering all but a single pair of eyes in each group tested. Occlusion of only one pair of eyes ata time has proven useful in several behavioural studies of salticid vision (c-g., Forster, 1979), In the present study of the lycosid spider Rabidosa rabida (Walckenaer), I used both methods of occlusion to examine the roles of different pairs of eyes in detecting visual stimuli and mediating appropriate responses. By using video images as stimuli (Clark and Uetz, 1990), 1 climinated the possibility that vibrations or chemicals from conspecifics could confound the results. METHODS AND MATERIALS Penulumate Rabidosa rabida (formerly Lycosa rabida) were collected in fate June (1990 and 1991) in Athens County, Ohio, USA. The methods of maintenance and the laboratory con- ditions during testing have been described pre- viously (Rovner, 1989). Spiders were not used in testing until | week after the final moult. Tests were conducted between 1000 and 2200 hours, For each test the spider's home cage, with its resident within, was placed with its narrow front side facing a small television set (black and white Magnavox BH-3907; screen = 9.2cm wide, 6.6cm high), which received a playback signal from a Sony recorder (SL-HFR70). The clear front side of the plastic cage (the other sides were Opaque) was 7cm wide and was located 3cm from the screen. | removed the cage cover and, if necessary, gently positioned the spider with an artist brush to insure that the screen would be within the visual field of the spider's useable eyes. (1 used separate brushes for males and females). Then, a glass coyer (one for each sex) was placed on top of the cage. A front-silvered mirror fixed at 45° to the floor was 0.5m above the cage. A video camera (IVC GX-8NU) was aimed at both the mirror and an adjacent, second, identical television set receiving the same signal from the playback recorder as the first set. This yielded (on a second, identical recorder) a kind of split-screen recording. On the left was a dorsal view of the spider, which facilitated the measure~ ment of turning angles (accurate to the nearest 5° ) and speeds of locomotion. On the nght was a view of the video image concurrently being presented to the spider. Thus, the relationship of 636 the video stimulus to the spider’s response could later be analyzed. Subjects used for video presentations were recorded against a plain, pale background and illuminated evenly by a 32-W, circular fluores- cent bulb 0.5m above the arena. The camera was located at a distance yielding a screen image the size of the actual subject (average body lengths: female=18mm; male=]12mm). The 15-min video playback for females was a pheromone-stimu- lated, courting male; his occasional position changes provided nearly equal proportions of anterior and lateral views of his display (total number of courtship bouts = 51). The 10-min video playback for males was a lateral view of a female walking to and fro in an elongate glass arena (passes across the screen =15 leftward and 15 rightward). Some preliminary tests made use of prey images provided by a 10-min video of three crickets (Acheta domesticus, 10mm body length) walking to and fro. To cover the eyes of spiders, I painted them with two coats of water-based enamel (Top Color Hobbylack, Pelikan AG). That this insured com- plete occlusion had been established previously (Rovner, 1989). Spiders were tested one or more days later. I ran two preliminary tests to see if painting or its related procedures lowered responsiveness. All the eyes of five females were covered with two separately applied coats of clear paint. Five other females were briefly anaesthetised (carbon dioxide) and then restrained for 6 hr, thereby duplicating the procedure used when painting the eyes. However, at the two times that paint would have been applied (0 hr and +3 hr), I used water instead. The next day, when exposed to video images of crickets, the clear-painted spiders were less responsive than were the water-brushed spiders. The latter seemed as responsive as un- treated spiders. There were three control groups, each with 10 females and 10 males; these 60 individuals were given two trials apiece. One group consisted of untreated spiders exposed to the conspecific video playback, to determine how readily fully sighted spiders respond. A second group, also untreated, was exposed to a 10-min video of an empty arena, to determine if that alone had a stimulating effect. (Light from the screen = about 800 lux; incident light from above = about 350 lux.). The third group consisted of fully blinded spiders exposed to the conspecific playback, to see if such spiders would perform behaviours (orientation, rapid approach, or display) that I MEMOIRS OF THE QUEENSLAND MUSEUM assumed would only occur in this study as visual responses. There were eight experimental groups, each having 10 spiders of each sex. In four experimen- tal groups a single pair of eyes was occluded; in four others, all but one pair was occluded. Since one of the untreated control spiders had failed to respond to video playback within two trials and since the preliminary tests had indicated that painting the eyes can reduce responsiveness, I gave unresponsive experimental spiders addi- tional opportunities to respond, up to a limit of five trials. One or more days separated consecu- tive trials undergone by any individual spider. RESULTS During testing of control groups, all of the untreated females and all but one of the untreated males showed ‘orientation’ and/or ‘long-range approach.” Most (16/20) did so in the first trial. ‘Orientation’ involved a single, rapid pivot that resulted in the spider facing the image. This pivot had a mean speed ( SD) of 121 +51.7°/s (N= 12), about eight times faster than turns that occurred during wandering, 16 + 12.4°/s (N= 11). A ‘long- range approach’ covered a distance of up to 10cm, the maximum being limited by cage depth (12.5cm). The speed of an approach, 5.9+3.32 cm/s (N = 22), was about ten times faster than walking during wandering, 0.6+0.31cm/s (N = 36). (The above speeds are not the maxima at- tained, since I included the acceleration and deceleration phases in each bout of locomotion.) No orientation or approach responses occurred in the empty arena or fully blind controls. Results of the eye occlusion experiments are summarized in Table 1. Spiders with any one of the four pairs of eyes occluded were still capable of orientation; those with occluded PME did not show approach. When all but one pair of eyes was occluded, the only group failing to show orienta- tion was the one limited to use of the AME; and the only group that still showed long-range ap- proach was the one with useable PME. When close to the cage front, a few spiders having only useable ALE did perform a near-field approach response, edging forward less than one body length. For all the responding experimental groups, the mean number of trials (+ SD) needed to obtain either an orientation or a long-range approach to the image was 1.2+0.53 (N= 63) for females and 2.4 + 1.24 (N=55) for males (Mann- Whitney U-test, Z= -6.545, P<0.0001). Spiders with useable PLE showed orientation VISUAL RESPONSES IN RABIDOSA RABIDA OnlyaLes [3 |r fa —o oo fontr ants Lolo In Jn —u fn TABLE 1, Number of ? and ¢ spiders responding to video playback. VN = 10 spiders/sex/condition. Bach spider was allowed more than one trial to respond: controls, up to two trials; experimentals, up to five trials, Only dd that also performed orientation or approach are included under ‘Display’. tums of up to about 160°. Those with only the PME useable performed orientation turns of up to about 50°. If near the stimulus, those with only the ALE useable showed orientation turns of up to about 20°. During playback of male courtship, only those females with non-occluded PME performed leg- Waving receptive displays (Table L). This brief display occurred 3.0+1.9s (NW = 30) after the abrupt termination of the male’s courtship bout. The receptive display was sometimes performed unimpeded, this being the case in females which had not yet reached the front of the cage. How- ever, it was usually constrained, since most females quickly approached the cage front and rested their anterior legs against the wall. Sull. the timing, of their response remained precise. Females showed this display while seeing anterior or lateral views of the courting male. Upto 6/10 of the males tested in each condition performed courtship display, which occurred in every group. Iteven occurred in two males during the empty arena playback and in three of the fully blinded males, such data reflecting a previously noted readiness of R. rabida to sometimes court in response to subnormal stimuli (Rovner, 1968). Perhaps these non-visually stimulated courtships were triggered by mechanical cues resulting from my moving the cage to the testing site or from my positioning the spider with a brush (to duplicate the procedure used on experimental spiders). For this reason, only courtships occurring during tri- alsin which orientation or approach also occurred were scored as visually initiated displays. (This 637 may have prevented some visually stimulated males that were facing the stimulus at the outset from being included in the courtship total for some experimental groups.) Only males with use- able PLE of PME showed courtship accompanied by orientation, andonly males with non-occluded PME showed courtship accompanied by ap- proach (Table 1). DISCUSSION Data presented here indicate that R. rabida’s posterior eyes play major roles in mediating responses to imporiant visual stimuli, as was ear- lier predicted for lycasids on anatomical grounds (Homann, 1931; Land, 1981). The PLE serve the same function that they do in salticid spiders, thal of detecting stimuli in an extensive visual field and initiating the largest orientation tums. They cannot mediate approach behaviour. On the other hand, the PME are essential for mediating rapid, long-range approaches to stimuli. They can also Inihate orientation lums of up to 50°. As to the anterior eyes, at clase range the ALE can play small roles in orientation and approach. This contradicts Land's (1981) suggestion that only the large posterior eyes are involved in prey capture. As predicted for lycosids by Land (ihid,), the AME of R. rubida play no role by themselves in mediating tums or approaches toward a targer. Whether they serve for other than polarized light detection (Magni et af.. 1964) remains to be ex- Plored. The present findings on the anterior eyes of R. rabida may not upply to all lycosids. For ex- ample, unlike R, nabida, in Arctosa variana the AME are larger than the ALE (ibid.). Also, local tienng is found in the rejinae of the AME of Geolycosa godeffroyi but not in the type genus Lycesa(Blestand O' Carroll, 1989), Furthermore, the finding of high noctumal sensitivity in the anterior eyes of Lycosa tarentula (Carricaburu et. al., 1990) suggests that an understanding of the capabilities of the anterior eyes of lycosids will require examining different species under various illumination conditions. Finally, I must point out that T did not test for any possible collaboration between different pairs of cyes. Collaborative visual mechanisms were revealed in salticid spiders by ipsilateral blinding (Forster, 1979). As in the salticids (Porster, 1985), orientation and approach are the initial behavioural respon- ses of lycosid spiders to moving images, whether prey or mating partners. Thus. the performaice of such behaviours docs not specify the spider's 633 motivational state. However, the fact that twice as many trials were needed to obtain these be- haviours in males as in females suggests that such initial responses relate primarily to predation, 1.e., that adult females, on average being hungrier than males, are more responsive fo visual stimulation. A subsequent occurrence of display behaviour indicates a switch to sexual motivation. For display to occur in females the PME have to be useable, and they are sufficient by themsel- ves for mediating this response. The fact that lateral as well as anterior views of the courting male elicited responses suggests that the cue is movement of the male's black leg I: it extends forward in a pumping-like motion of increasing frequency and then abruptly flexes back. Unlike sallicid face-to-face courtship, in which the per- ceived form of the male may be as important for the female as his behaviour (ibid.), female RF, rabida need not view the male's antenor, Ap- parently, detection of a temporal pattern of move- ment suffices for recognition. As to visually-triggered courtship display, male R. rabida differ from male salticids, which re- quire one particular pair of eyes, the AME (ihid.), Stimulation of either pair of a male R. rabidea's posterior eyes suffices for triggering courtship, If the PLE are involved, orientation precedes dis- play. If the PME are involved, approach can precede display, although it need not do so. Given that the movement-detecting PLE are sufficient for courtship onset in R, rabida, an adequate stimulus in this species may be any object of an appropriate size, speed, and perhaps movement pattern entering the extensive visual field of the PLE. Since the other three pairs of lycosid eyes are also assumed to be movement detectors (Land, 1981), there may be no need to require their involvement in additional visual analysis before initiating courtship. However, this may not be true for all lycosids. In particular, female Pardosa laura have been hypothesized to use form vision for species discrimination (Suwa, 1984). If male P. laura likewise do so, eyes other than the PLE would be have to be used for such form analysis in order to inititate courtship. MEMOIRS OF THE QUEENSLAND MUSEUM LITERATURECITED ACOSTA, J., ORTEGA, J. & RODRIGUEZ- SANABRA, F. 1982. Vision and predatory be- haviour in Lycosa _fasciiventris, 6th European Neuroscience Congress, Malaga, Spain: 21-22, BLEST_A.D. & O'CARROLL, D. 1989. The evolution of the tiered principal retinae of jumping spiders {Araneae: Salticidae), Pp, 155-170, In R.N. Singh and N.J. Strausfeld (eds). “Neurobiology: of sen- sury systems”. (Plenum Press: New York). CARRICABURU, P., MUNOZ-CUEVAS, A. & OR- TEGA-ESCOBAR, J. 1990, Electroretinography and circadian rhythm in Lycosa tarentula (Araneae, Lycosidae), Acta Zoologica Fennica 190: 63-67. CLARK, D.L. & UETZ, G.W. 199). Video image recognition by the jumping spider Maevia inclem- ens (Araneae: Salticidae). Animal Behaviour 40: 884-890, FORSTER, L.M. 1979. Visual mechanisms of hunting behaviour in Trife plarticeps, a jumping spider (Araneae: Salticidae). New Zealand Journal of Zoology 6: 79-93. 1985. Target discrimination in jumping spiders (Araneae:Salticidae), Pp. 249-274. In F.G, Barth (ed). ‘Neurobiology of arachnids’. (Springer- Verlag: New York). HOMANN, H. 1931. Beitriige zur Physiologie der Spin- nenaugen. [1]. Das Sehvermégen der Lycosiden. Zeitschrift fiir Vergleichende Physiologie 14: 40- 67, LAND, M.F. 1981. Optics and vision in invertebrates. Pp. 471-592, In H. Autrum (ed). ‘Comparative physiology and evolution of vision in inver- tebrates. Handbook of sensory physiology VIV6B’. (Springer-Verlag: New York). MAGNI, F.. PAPL F., SAVELY, H.E. & TONGIORGI, P, 1964. Research on ihe structure and physiology of the eyes of a lycosid spider. I. The role of different pairs of eyes in astronomical onentation. Archives laliennes de Biologie 102: 123-136. ROVNER, J.S. 1968. An analysis of display in the lycosid spider Lycosa rabida Walckenaer. Animal Behaviour 16: 358-369. 1989. Wolf spiders lack mirror-image responsive- ness seen in jumping spiders. Animal Behaviour 38: 526-533. SUWA, M. 1984. Courtship behavior of three new forms in the wolf spider Pardosa Idure complex. Journal of Ethology 2: 99-107. THE SPATIAL DYNAMICS OF LINYPHIID SPIDERS IN WINTER WHEAT K.D, SUNDERLAND anp C.J. TOPPING! Sunderland, K.D, and Topping, C.J, 1993 11 11; The spatial dynamics of linyphiid spiders in winter wheal. Memoirs of the Queensland Museum 33 (2): 639-44. Brisbane. ISSN 0079-8835. The density of linyphiid spiders was monitored accurately throughout the growing season in a field of winter wheat in southeast England m 1990 and 1991. Numbers increased until harvest in 1991, butdeclined before harvest in 1990, possibly duc to dronght conditions. The pattern of natality in 1991 closely mirrored the pattern of change in density, suggesting that reproduction, rather than immigration, was the predominant factor underlying the increase in density. Aenal activity, as measured by deposition traps and a rotary trap in the field, and a suction trap at the edge of the field, increased progressively during the growing season. Results from @ short-term field caging technique, used to measure net migration rates, indicated that there was little immigration before July (thereafter high sampling variance, caused by aggregation in weedy patches, precluded meaningful analysis).QAraneae, Linyphiidae, spatial dynamics, winter wheal, density, natality, migralion. Reith Sunderland and Chris Topping, Horticulture Research International, Litlehampien, West Sussex BNI7 6LP, England; current address, Scottish Agricullural College, Craibsione, Bucksburn, Aberdeen AB2 9TR, Scotland, UK; 8 September, 1991. There are few studies of the population dynamics of predators. For example, Stiling (1988), in an examination of the incidence of density-dependence in invertebrate populations, quotes 62 population dynamics studies; of these 60 relate to phytophages, 2 to parasitoids and none to predators. There are also few population dynamics studies of migratory species, because of the methodological problems involved in quantifying migration. The present study, of the population dynamics of linyphiid spiders (the species concerned are all migratory predators), was undertaken to collect some basic data in this neglected area, and also because these species are known to be valuable predators of crop pests (Sunderland e7 al, 1986). This paper summarises the main trends for total lmyphiids; consideration will be given to individual linyphtid species in later publications. METHODS AND MATERIALS Total spider density was measured throughout mostof the growing season of 1990 ina 17ha field of winter wheat (c.v. Pastiche) in southeast England. In 1991, density, natality and migration Were measured in a 3ha field of winter wheat (c.¥. Riband), 24km from the 1990 study field. The fields were treated with agrochemical applica- tions, following normal farm practice; insec- licides were not required in either year. Denstry SAMPLING Twenty-five 144m? squares were marked out inside a 60 x 60m area (adjacent to one edge of the field in 1990 and 30m from the nearest edge in 1991). Fifteen density samples were taken at each sampling interval (approximately weekly) following a Latin Square design. The sample untt consisted of a randomly-selected 0.5m* area of ground delimited by a metal ring and sampled using a vacuum insect net (D-vac). Vegetation and the top lem of ground, within the 0.5m* sampled by D-vac. were then immediately hanil- searched for spiders, The suction catch was kept at 10°C and returned to the laboratory for live- sorting. Therefore spiders were collected from 7.5m? of habitat (crop, ground surface and imme- diate sub-surface) on each occasion (Topping and Sunderland, 1992). The D-vac collected only about 50% of the total number of spiders present in a sample unit, the other 50% were uncovered by hand-searching (see also Sunderland ef al., 1987). NATALITY Adult female linyphiids were collected from the field, adjacent to the 60 x 60m area, at weekly intervals and incarcerated individually in 9cm diameter plastic Petri dishes lined with moist filter paper. The dishes were returned immedi- ately to a ventilated box in the study field and examined at weekly intervals. Mean daily temperatures in the Petri dishes did not diverge from field temperatures (measured on the ground 640 surfuce, under weed caver) by more than 1°C (warmer in spring, cooler in summer). The dishes were inspected at weekly intervals and the fol- lowing statislics recorded [i) proportion of spiders producing eggsacs in the first week of incarceration, (ii) time (days) to emergence of spiderlings, (iii) number of spiderlings emerging, and (iv) number of undeveloped eges (by dissec- tion of the eggsac). These resulls were used, in conjunction with information on the density of adult females, to caleulate daily natality rates for each species and then combined to give 2 com- posite spider natalily curve, Net MiGRaATION RATE Migration to and from small areas of the crop wus suppressed by the use of ten stainless steel spider-proof cages. The cages were circular, 0.5m? by Im tall, and made of mesh with 3 x 2,5 perforations mm (too small to allow passage of first instar linyphiid spiders). The bases of the cages were sealed with sufficient compacted soil to prevent entry or exit of any spiders. Total spider density inside the cages was assessed as above. Because the cages were moved to a new location within the Latin Square each week, there Was assumed to be imsuffictent time for the processes of natality and mortality to be sig- nificantly affected by the changed microclimate inside the cages; therefore differences in the change in density from one week to the next between caged and uncaged parts of the crop were considered to be a measure of net nigeation, AERIAL DENSITY OF SPIDERS A46cm Propeller Suction Trap (Taylor, 1955), with an air throughput of 70m? min“ and a sam- pling height of 142cm above the ground surface, located at the edge of the study field, was emptied daily. In addition, a rotary insect net was used to collect spiders within the field, 25cm above the lop of the crop canopy. The 10m long rotor arm travelled at 6.3m sec? and the 56 x 25cm net at the end of the rotor arm (which was designed to sample air isokinetically, (Taylor. 1962)) processed 53.8m? min! and was also emptied daily. To measure rates of input of spiders into the field, a set of seven deposition traps were deployed at 15m intervals between the rotor and the 60 x 60m area. Each trap consisted of a 10cm deep, Im?, fibreglass tray, filled with water and ethylene glycol (20:1) plus 1% detergent, fitting inside a 1.6m? metal tray containing the same fluid.. The outer tray acted as a barrier to prevent spiders walking from the crop into the inner tray, MEMOIRS OF THE QUEENSLAND MUSEUM which therefore received only aerial Immigrants. As the crop grew, the deposition traps were progressively raised on wooden supports to main- tain the level of the fluid surface constantly at ca. 5cm above the top of the crop canopy, The traps were emptied at approximately weekly intervals. Nomenclature follows Roberts (1987). RESULTS The study was based on data from more than 39,000 individuals belonging to 53 species, 12 species were dominant (Table 1). All species belong to the family Linyphiidae, with the excep- tion of the tetragnathid Pacliygnatha degeeri. Lepthyphantes tenuis was the most abundant species in 199] and the second most abundant in 1990. Species composition was similar in the two years, the only notable differences being that Meioneta rurestris was relatively more abundant in 1990, the reverse being true for Oedothorax spp. Here, all spiders are treated as a group, In 1990, density of total spiders increased in spring to reach a peak of 78m-* on 18 June and thereafter declined, apart from a short-lasting peak (made up entirely of immature spiders) just before harvest (Fig. 1). The pattern was different in 1991 (Fig, 2); spider density built up in two steps (the firstin May/June, the second in August) to reach a peak of 123m just before harvest. Mean air temperatures in June and July were slightly higher in 1990 (15.1°C) than 1991 (14.9°C), but rainfall was considerably lower (68mm in 1990 cf 19imm in 1991), The semi- drought conditions in the summer of 1990 may have had a deleterious effect on spider survival. TABLE |. Species composition of adult spiders in density samples in 1990 (n=1562) and 199] (n= 1457). SPATIAL DYNAMICS OF LINYPHIIDS 100 ;- SPIDER DENSITY IN A FIELD a tas OF WINTER WHEAT - IN 1990 a \ | Harvest ve 60 + ‘ = 20k Ww aoe L ey “f ii eat L i 1 1 1 1 1 L j___| 1 Jan Feb Mar Apr May Jun Jul Aug Sep SPIDER DENSITY IN A FIELD OF WINTER WHEAT IN 1991 (solid line) Me | Harvest 95% CL OF MIGRANTS (vertical dashed line) Mean number m7?(95% GL) ot é a oe L 1 | i 1 i | | L J 2 lan Feb Mars Apr_—s May”=—s uns Jul.=S=s Ags 120 joo + SPIDER DENSITY IN CAGED 5 | AREAS OF WINTER WHEAT Zao f IN 1991 Aly = Harvest eh : : A be 2 5 40+ \, 2 ao} / 7 i ok L +L 1 1 L 4 L 4 1 | 3 Jan Feb Mars Apr_—S ss May”—s duns ul’,—s—s Aug’—sSep FIGS. 1-3. Total spider density in a field of winter wheat: 1990 (Fig. 1); 1991 {solid line) and 95% CL of number of migrants m™~ (vertical dashed lines) (Fig. 2); in caged areas, 1991 (Fig. 3). Density in the caged areas of the crop in 1991 followed a similar pattern to that in uncaged areas (Fig. 3). 95% confidence limits increased during July and August (Figs 2, 3) due to aggregation of spiders in weedy patches of the crop (significant- ly more spiders in weedy than bare areas; paired t-test, n = 5 dates, p= 0.05). The pattern of change in density with respect to time is examined, below, in relation to natality and migration for 1991. Natality rates were c. 4m? day’! in the spring, briefly 10-15m‘? day” in late July, then 8m~* day"! in August. The pattern of daily natality was similar to the patterns for immature spider density (Fig. 4) and total spider density (Fig. 2); this is 641 Date M 95% CL 2.1 (-1.2-5.4) 23 April (23-62) 1 May -2.0 (-8.7- 4.7) 14 Ma 2.7 (-11.8-17.2) 21 Ma -12.8 (-29.5- 3.9) 11 June -16.5 -33.9-0.9) 18 June -8.0 (-23.1- 7.1) 0.7 (-13.2-14.6) (-10.4-16.2) 17 Jul (-26,7-16.5) 23 Jul 18 (-20.5-24.1) 29 Jul -9.5 (-43.8-24.8) 5 August 24.2 (-19.9-68.3) 19 August 12.7 (-41.4-66.8) 9 September -10.0 (-52.7-32.7) (-19.6-33.8) TABLE 2. Indices of net aerial migration, M (95% CL), in 1991. circumstantial evidence that reproduction (as op- posed to immigration) is the predominant process driving increase in density of spiders in the field. Data on migration can be examined in the light of this hypothesis. Aerial activity of spiders, as measured by catches in the 1.4m suction trap at the edge of the field, tended to increase steadily from March to August, and this was followed by a much larger increase in September (Fig. 5). A similar pattern of aerial activity was evident in- side the field, as indicated by the catch in deposi- tion traps and in the rotary trap (Fig. 6). To assess whether there had been a a net gain or loss of spiders from the field over a particular period, the density of spiders inside caged areas was com- pared with the density outside,to give an index of net migration (M); M = (F2-F1)-(C2-F1) = F2-C2 where F1 and F2 are densities in the uncaged part of the field in weeks 1 and 2 respectively, and C2 is the density in the caged part of the field in week 2. (F2-F1 represents change in numbers due to natality, mortality and migration, whereas C2- Fl represents change in numbers due to natality and mortality alone, because migration was sup- pressed by caging). The standard error of M is calculated as the square root of [SE F2? + SE C22]; the 95% CL’s on M are therefore large because they are compounded of two standard errors. Values of M are shown in Table 2. Positive values indicate immigration and negative values indicate emigration. However, all 95% CL’s span the range from negative to positive and therefore no significant net migration can be demonstrated. 642 100 » at of \inavest 1s 60 | Aun 1" | ne 1 Mean number m @ “ui payiniaai sBuiepids jo uaqunu ueay z L ° l i a: dan Feb ° ,Aep 1 ° L L | Mar = Apr May Ju Jul Aug Sep FIG. 4. Total immature spider density ( @) and total spider natality (continuous line) in a field of winter wheat in 1991. These 95% CL’s are plotted on the curve of total spider density (Fig. 2); the extent of the dotted line above and below the density curve shows the amount of immigration and emigration, respec- tively, that could have occurred between any two dates. The following conclusions can be drawn; (i) any migration that may have occurred in April was small (i.e. on a similar scale to density sam- pling variance), (ii) if immigration occurred in May and June it must also have been on a small scale, but there could have been a large emigra- tion, and (iii) in July, August and September 95% CL’s were very large (due to spider aggregation, see above), with no obvious bias in favour of either immigration or emigration. DISCUSSION There appear to be no previous quantitative arachnological studies in which the seasonal pat- terns of natality and migration are compared with the seasonal pattern of density using consistent units. Examples of other arachnological studies involving density or natality estimation are given below. The majority of investigations where den- sity has been measured are for grassland; peak MEMOIRS OF THE QUEENSLAND MUSEUM 100 ;— DAILY CATCH OF SPIDERS IN A 1.4 M SUCTION TRAP AT THE EDGE OF A FIELD OF WINTER WHEAT IN 1991 80 [- 60 40 + 20 7-point running mean of number caught per day DAILY CATCH OF SPIDERS e IN A ROTARY TRAP and IN 7 SQ M OF O / DEPOSITION TRAPS ~ . IN A FIELD OF WINTER WHEAT IN 1991 60 40 ® oO ia 1 1 r J 0 ‘| *, e~ 007 \ cia cee 20 Mean number of spiders caught per day o--0-. of BE059/ l L pe eye Hy Fee ee pet tee by oY FIGS. 5, 6. Daily catch of total spiders in winter wheat field in 1991.5.In 1.4m suction trap at edge of field; 6. In rotary trap (@) and in 7m* of deposition traps . densities of lycosid and linyphiid spiders vary greatly according to location (Table 3). Densities are often lower in graminaceous crops (Table 3). The peak spider density of 123m in the present study is comparable with, if somewhat greater than, densities recorded in cereals by other authors (Table 3). In common with the present investigation, nearly all the studies in Table 3 reported large confidence limits due to aggrega- Species Family Habitat Density __| Author(s) Geolycosa godeffroyi (L.Koch) _ | Lycosidae [pasture Humphreys, 1976 Trochosa terricola Thorell Lycosidae rass heath Workman, 1978 Total spiders 4 Total spiders Oedothorax and Erigone winter wheat Linyphiidae Pardosa palustris (Linnaeus) Lycosidae alpine meadow Steigen, 1975 TABLE 3. Oedothorax fuscus (Blackwall) _| Linyphiidae asture De Keer and Maelfait, 1987 Maximum d ensity Erigone atra (Blackwall) Linyphiidae | pasture 318 De Keer and Maelfait, 1988 estimates (number Erigone arctica (White) Linyphiidae | dune grass 330 van Wingerden, 1977 nm ) ina range of Total spiders [ Festuca grass __|840 Duffey, 1962 arachnological studies. Alderwiereldt, 1987 Alderwiereldt, 1987 Nyffeler and Benz, 1988 Total linyphiids winter wheat Fraser, 1982 Total spiders winter wheat Sunderland 1987 SPATIAL DYNAMICS OF LINYPHITDS lion of spiders. There seem to be no previous publications describing the seasonal pattern of spider natality, but a few authors (eg Steigen, 1975; Workman, 1978) have recorded natality at specific times of year. Schaefer (1978) estimated the egg density of the linyphiid Floronia buc- culenta in grassland during the spring to be 98- 151m? depending on location. The maximum spring natahty of the linyphiid Erigove arctica in coastal grassland was claimed to be 2584m (van Wingerden, 1977), which is considerably greater than the total natality (8 dominant linyphiids) of 789m? between March and October in the present siudy; this difference may underly the relative sparseness of spiders in crops compared with nitural grassland (Table 3). Although the inten- sity of aeronautic activity has been measured using sticky traps (Duffey, 1956, van Wingerden, 1977, Greenstone e¢ al., 1985), window traps (Meijer, 1976; De Keerand Maelfair, 1987, 1988) and suction traps (Dean and Sterling, 1985; Sunderland, 1987, 199]), there appear to be no previous attempts to directly quantify the impact of migration on population density. The use of short-term field cages in the present study provided useful estimates of the upper limits to migration (except when sampling vanance be- came very large) and it is expected that this technique will yield better results when data are analysed for individual species. In addition, when the rotary trap has been calibrated, it should be possible to estimate rates of aerial immigration and emigration from a comparison of deposition and rotor catches. ACKNOWLEDGEMENTS We thank Mr Bewsey and Mr Reeves (HRI) for constructing the rotary trap, Mr Fenton (HRI) for statistical advice, and Dr Jepson and Mr Thomas (Southampton University) for useful discussions. The work was funded by the Natural Environ- ment Research Council (Joint Agriculture and Environment Programme) and the Ministry of Agriculture, Fisheries and Rood. The first author is grateful to the British Council for the oppor- tunity to deliver this paper in Australia. LITERATURE CITED ALDERWEIRELDT, M. 1987. Density fluctuations of spiders on maize and Italian ryeprass fields. Mededelingen van de Pakulteit Landbouw- wetcnschappen Riyksuniversitest Gent 52: 273- 282 DEAN, D.A. & STERLING, WL. 1985, Size and phenology of ballooning spiders at two locations in eastern Texas. Journal of Arachnology 13: 111- 120, DE KEER, R. & MAELPAIT, J.P. 1987, Life history of Oedothorax fuscus (Blackwall, 1834) (Araneae, Linyphiidae) in a heavily grazed pasture, Revue d’Ecologie et de Biologie du Sol 24: 171-185, 1988. Observations on the life cycle of Erigone atra (Araneae, Erigoninae) in a heavily grazed pas- ture, Pedobiologia 32: 201-212. DUFFEY, E, 1956. Aerial dispersal in a known spider population. Journal of Animal Ecology 25: &5- ii. 1962. A population study of spiders in limestone grassland. Journal of Animal Ecology 31: 571- 59). FRASER, AM. 1982. ‘The role of spiders in determin- ing cereal aphid numbers'. Thesis (University of East Anglia) 121 p. GREENSTONE, M.H.. MORGAN, C.B. & HULTSCH, A.L. 1985. Spider ballooning> development and evaluation of ficld trapping methods (Araneae). Joumal of Arichnology 13- 337-345. HUMPHREYS, W.F. 1976. The population dynamics of an Australian wolf spider, Geolycosa godef- froyi (L, Koch 1865) (Araneae: Lycosidae), Jour- nal of Animal Ecology 45 : 59-80. MEIJER, J. 1976. The immigration of spiders (Araneida) into a new polder. Ecological En tomology 2: 81-90. NYFFELER, M..& BENZ, G. 1988. Prey and predatory importance of micryphantid spiders in winter wheat fields and hay meadows. Journal of Applied Entomology 105; 190-197, ROBERTS, M.J, 1987, ‘The spiders of Great Britain and [reland, Vol, 2.\(Harley Books; Colchester, England} SCHAEFER, M. 1978. Some experiments on the regulation of population density in the spider Floronia bucculenia (Araneida: Linyphiidae). Symposia of the Zoological Society of London 42: 203-210. STEIGEN, A.L. 1975, Energetics in a population of Pardesa palustris (L,)(Araneae, Lycosidae) on Hardangervidda, Pp, 129-144. In F, Wielgokski (ed). ‘Fennoscandian tundra ecosystems Part 2". (Springer: Berlin). STILING, P. 1988, Density-dependent processes and key factors in insect populations. Journal of Animal Ecology 57: 581-593. SUNDERLAND, K.D. 1987. Spiders and cereal aphids am Europe. Bulletin SROP/WPRS L987/X/1; 82- 102. 1991. The ecology of spiders in cereals. Proceedings of the 6th International Symposium on Pests and Diseases of Smal! Grain Cereals and Maize. Board of Plant Protection, Halle/Saale, Germuny 1:269-280, SUNDERLAND. K D., FRASER, A.M. & DIXON, A.P.G. 1986. Field and laboratory studies on money spiders (Linyphiidae) as predators of cereal aphids. Journal of Applied Ecology 23: 433-447. SUNDERLAND, K.D., HAWKES, C., STEVENSON T., MCBRIDE, L.E., SMART, L.E., SOPP, P.I., POWELL, W., CHAMBERS, R.J. & CARTER, O.C.R. 1987. Accurate estimation of invertebrate density in cereals. Bulletin SROP/WPRS 1987/X/1; 71-81. TAYLOR, L.R. 1955. The standardization of air-flow in insect suction traps. Annals of Applied Biology 43; 390-408. 1962. The absolute efficiency of insect suction traps. Annals of Applied Biology 50: 405-421. MEMOIRS OF THE QUEENSLAND MUSEUM TOPPING, C.J. & SUNDERLAND, K.D. 1992. Limitations to the use of pitfall traps in ecological studies exemplified by a study of spiders in a field of winter wheat. Journal of Applied Ecology 29: 485-491. WINGERDEN, W.K.R.E. VAN 1977. ‘Population dynamics of Erigone arctica (White) (Araneae, Linyphiidae)’. (Thesis, Free University: Amster- dam). 147pp. WORKMAN, C. 1978. Life cycle and population dynamics of Trochosa terricola Thorell (Araneae: Lycosidae) in a Norfolk grass heath. Ecological Entomology 3: 329-340. MORPHOLOGY OF THE EMBRYOS AT GERM DISK STAGE IN ACHAEARANEA JAPONICA (THERIDIIDAE) AND NEOSCONA NAUTICA (ARANEIDAE) HIROHUMI SUZUKI AND AKIO KONDO Suzuki, H. and Kondo, A. 1993 11 11: Morphology of the embryos at germ disk stage in Achaearanea japonica (Theridiidae) and Neoscona nautica (Araneidae), Memoirs of the Queensland Museum 33(2): 645-649. Brisbane. ISSN 0079-8835, Embryos at the germ disk stage were investigated by electron microscopy in Achaearanea Japonica (Theridiidae) and Neoscana nautica (Araneidac), In both spiders, the germ disk was Composed of spherical cells, which had almost no Jarge yolk granules, In the inner part of the embryo, several large yolk granules were packed by cell membrane with various organelles and glycogen granules similarly to lyeosid spiders. InAchaearanea japonica there were very lat cells which possessed several large yolk granules in the surface region where the germ disk was not formed, In Neoscona nautica cells Were not observed in that region at all,,so the packages of large yolk granules were exposed directly to perivitelline space. The araneid type can be distinguished from the agelenid and theridiid type. Die Embryonen vonAchaearanea japonica (Theridiidae) und Neoscona nautica | Araneidae) im Stadium der Keimscheibe wurden mittels des Elektronenmikroskops untersucht. Die Keimscheiben der beiden Spinnen bestanden aus spharischen Zellen, die groBe DotterkGmchen nur selten hatten. In dem inneren Teil von dem Embryo wurden manche groBen Dotterkérnchen mit verschiedenen Organellen und Glykogenkornchen von der Zellmembran gepackt, wie im Falle von den lycosiden Spinnen. Im Falle von Achaearanea japonica gab es sehr Mache Zellen, dié manche groben DotterkGmehen hatten, in dem oberflichtichen Bezirk, wo dic Keimscheibe nicht gebildet wurde. Im Falle von Neoseona naulice wurden die Zellen in dem Bezirk schlieBlich nicht beobacht, also waren die Packe von grolen DotterkOrmmchen direkt in der Perjvitellinhohle entbloBt. Der araneide Typus soll sich vou dem ageleniden Typus und dem theridiiden Typus unterscheiden. (Spider. Achaearanea, Neoscona, embryo, germ disk, morphology. Hirohumi Suzuki and Akio Konde, Department of Biology, Faculry of Science, Toho University, 2-1, Mivama 2 chome, Fanabashi-shi, Chiba 274, Japan; 29 October, 1992. Three types of germ disk formation are known in the embryos of spiders. In the most common type known in Agelenidae, the germ disk is formed on a hemisphere of the egg as the result of transformation of squamous blastoderm cells in this region into spherical cells. Egg surface of the other hemisphere is covered with squamous cells (Holm, 1952). In the second type known in Theridiidae, the most blastoderm cells converge FIG. L. The embryo at germ disk stage in Achaearanea japonica (a) and Neescona nanlica (b). In A. japonica, afew cells are found on region where germ disk is not formed. In N. nowlica, exposed yolk mass is found on thal region, Scale=0.2mm. on the germ disk region and few cells remain on the other hemisphere (Montgomery, 1909). In the third type found in many Araneidae, a rip appears in the blastoderm, so the yolk mass is exposed (Sekiguchi, 1957), Then all blastoderm cells take part in germ disk formation, and any cells are not observed in the region where the germ disk is not formed. A comparative study of the spider embryos at germ disk stage was carried out under light microscope (Kondo and Yamamoto, 1975). The study of germ disk formation under electron microscope was executed in lycosid spiders, whose germ disk formation is the agelenid type (Kondo, 1969, 1970). We had to examine whether remaining cells connect each other or not in theridiid type and whether extreme thin cells exist or not at the superficial region where the germ disk is not formed in araneid type. In present study, electron microscopic investigation of the embryos at germ disk stage was carried out in Achaearanea japonica and Neoscona nautica. 646 MEMOIRS OF THE QUEENSLAND MUSEUM FIGS. 2-8. 2. A. japonica. Peripheral region of two germ disk cells. (0.5.m.) Arrowhead: Desmosome-like structure, 3. A mid-body. Many microtubules. (1jzm.) 4. A germ disk cell. Main components of cytoplasm are fatty granules (fg) with medium electron dense matrix, and no large yolk granules. (10j.m.) n: nucleus, ne: nuclear envelope. 5. Mitochondria have high electron dense matrix and the cristae are found faintly. (0.5.m,) 6. Cup-shaped mitochondrion. (0.5j.m). cm: cell membrane. 7. Ring-shaped mitochondrion. (0.5,.m.) 8. Fatty granule (fg) lacking complete limiting membrane, but partly enclosed by smooth-surfaced endoplasmic reticulum (er). (1j1m.) gg: glycogen granules, m: mitochondria, ps: perivitelline space. Scales in parentheses. EMBRYO MORPHOLOGY IN TWO SPIDERS MATERIALS AND METHODS Achaearanea japonica (Bésenberg and Strand} (Theridiidae) and Neoscona aautica (L. Koch) (Araneidae) were used here. In A. japonica, the eggs collectedin August were used, InN. nautica, the eggs laid in glass tubes at laboratory were used_ The observation of the live eggs was carried out in liquid paraffin, where the opaque chorion became transparent. The eggs were fixed for 3 hours at 4°C in 2% paraformaldehyde and 2.5% glutaraldehyde solution in 0.1M phosphate buff- er, pH 7.4, containing 0,2M sucrose, Through fixation, the eggs were cut in half with a tungsten needle. After rinsing more than one hour with the same buffer containing 0,.2M sucrose, the samples were postfixed for one hour at 4°C in 2% osmic acid in 0.1M phosphate buffer, pH 7.4, without sucrose, After rinsing with the same buff- er without sucrose, samples were dehydrated in ethanol series, transterred to propylene oxide, und embedded in Quetol-812. Ultrathin sections were cut on a ultra-microtome, LKB-4800, stained with uranyl acetate and lead citrate, and examined under Hitachi HU-12A electron micro- scope. Thick sections were prepared simul- tancously, and stained with methylene blue for light microscopy. RESULTS AUCHAEARANEA JAPONICA The eggs were spherical and 0.5mm in diameter. Typical theridiid type germ disk forma- lion was observed (Fig. la). At 25°C, the eggs took 24 hours to the germ disk stage after oviposi- ton, The germ disk was formed as a single layer composed of spherical cells, but the cells piled up in its central region. The diameter of germ disk cells was about 30j.m, and that of nuclei was about 15m. Desmosome-like structures were observed between germ disk cells at the superfi- cial region (Fig. 2), but interdigitations were not observed, Mid-hodies were observed rarely (Fig. 3). Narrow cytoplasmic bridge connected cells adjacent to each other, and contained many microtubules. The main components of cytoplasm were fatty granules, 1-3,.m in diameter, with a matrix of a medium electron density (Figs 4,8). The limiting membrane was often obscure. The germ disk cell had almost no large yolk granules, Fine yolk Brenuien less than 5um in diameter, were ob- served. O47 Mitochondna had a high electron dense matrix, and the cristae were found faintly (Fig. 5). Many figures of mitochondria showed oval or curved bars, and several showed cups (Fig. 6) or rings (Fig. 7). Smooth-surfaced endoplasmic reticula were often found enclosing fatty granules (Fig. 8). Rough-surfaced endoplasmic reticula were not observed. Typical Golgi bodies were rare. Vesicles were generally observed in the cytoplasm, The glycogen granules, 0.1,.m in diameter, were very high electron dense, and scattered. The superficial region where the germ disk was not formed was occupied by remaining flat cells. These cells were about 100m in length. about 254.m in thickness at the central part, but often less than Ijsm near the peripheral one (Fig. 9). The diameter of nuclei was about 13m. Des- mosome-like structures were observed between remaining cells (Fig. 9). Several large yolk granules occurred in these remaining cells. The largest yolk granule was 20m in diameter. Vesicles were sometimes ar- ranged along the large yolk granules (Fig. 10), The interior of the embryo was filled with yolk packages composed of several large yolk granules, various organelles and glycogen granules. and enclosed by cell membrane (Fig. t]). NEOSCONA NAUTICA Ellipsoidal eggs of NV. nautica had longer axis measuring 1.2mm and shorter axis measuring Imm. At 23°C, 45 hours were needed from oviposition to establish the germ disk (Fig. 1b). The germ disk was a single layer of spherical cells, but the cells piled up in its central region. The cell diameters were about 45m, and those of nuclei were about 20pm. Between these cells, there were desmosome-like structures but no in- terdigilations. Various types of lysosome-like bodies were observed (Figs 12-14). Mitochondria often crowded around the nucleus (Fig. 15). Several Golgi bodies were observed (Fig. 16). Othercom- ponents of cytoplasm were similar to those of A- japonica, No blastoderm cells were observed in the sur- face region where the germ disk was not formed (Fig. 17). DISCUSSION In this study. some cup- or ring-shaped 648 MEMOIRS OF THE QUEENSLAND MUSEUM mitochondria were observed. These types of were figured in embryo of A. ftepidariorum mitochondria were not reported inthe embryos of (Suzuki and Kondo, 1991). In NV. nautica, many lycosid spiders (Kondo, 1969, 1970), but they mitochondria were found surrounding the EMBRYO MORPHOLOGY IN TWO SPIDERS dvubararanes jJeporsou Momecane FIG. 18. Schematic figures of embryos at germ disk stage in A, japonica (left) and N. nautica (rig). In both spiders, the germ disk is composed of spherical cells, which have almost no large yolk granules. The interior of the embryos is filled with yolk packages (yp). In A. juponica, there are very flat cells which possess several large yolk granules in the surface region where the germ disk is not formed, In \. nautica, any cells are not found in that region, so the yolk packages are exposed directly to perivitelline space (ps), ym\ vitelline membrane, nucleus. This phenomenon was reported in lycosid spiders (Kondo, 1969), In N. nautica, many lysosome-hke bedies. descnbed also in lycosid spiders (Kondo, 1969), were observed, however histochemical studies are needed for final identification. In both spiders, A, japonica and N. nautica, interdigitations were not observed, but they were reported in germ disk region of lycosid spiders (Kondo, 1970). In the inner part of the embryo in both spiders, several large yolk granules were packed by cell membrane with various organelles and glycogen granules. These structures were described as yolk spheres in lycosid spiders (Kondo, 1969), Since nucleus was not observed in them, these packages of Jarge yolk granules were distinguished from 649 yolk cells. In this investigation, detailed observa- tion of yolk cells was not carried out. The embryo at germ disk stage in A. japonica had very flat cells with several large yolk granules (Fig. 18). Distinct differences of cytoplasm were not observed between spherical germ disk cells and flat remaining cells. As in A. tepidariorum {Suzuki and Kondo, 1991), except for the large yolk granules and extreme flat shape in the remaining cells, the fine structure of embryo at germ disk stage in A. japonica was similar to that in lycosid spiders belonging to agelenid type. InN. nautica, the yolk packages were exposed directly to the perivitelline space (Fig. 18). LITERATURECITED HOLM, A. 1952. Experimentelle Untersuchungen liber dic Eotwicklung und Entwickluogsphysiologic des Spinnenembryos. Zoologiska Bidrag fran Up sala 29; 293-424, A. 1969. The fine structure of the carly spider embryo. The Science Reports of the Tokyo Kyoiku Daigaku, Section B 207; 47-67. }970. Morphological study on {he spider's embryonic cells at germ disk stage. Japanese Journal of Developmental Biology 24; 20-21. (in Japunese) KONDO, A. & YAMAMOTO, N. 1975. Comparative morphology on the early spider embryos. Atypus 63) 13. (in Japanese) MONTGOMERY, T. H. 1909. The developmen of Theriajum, an Aranead, up to the stage of rever- sion. Journal of Morphology 20: 297-352. SEKIGUCHI, K. 1957. Reduplication in spider eggs produced by centrifugation. The Science Reports al the Tokyo Kyoiku Daigaku Section B §: 227- 7 KON SUZUKI, H. & KONDO, A. 1991. Fine structure of the germ disk in the thendiid spider, Achaearanen lepidarionen (C. Koch). Proceedings of Anhropodan Embryological Society of Japan 26: 11-12. FIG. 9-17. 9-11, A. japonica 9. Extreme flat shape in peripheral part of remaining cells. A desmosome-like structure (Arrowhead) is found between cells. (Jum). 10. A large yolk granule included in remaining cell, Arranging vesicles along yolk granule, (O.5,:m). 11. Peripheral pari of yolk package in inner part of embryo. Large yolk granules, a ring-shaped mitochondrion (m), vesicles (v). and glycogen granules (arrowhead) are packed by ccll membrane, (1 jm). 12-17.N. neutica 12. A lysosome-like body including amorphous matrix, A ring-shaped mitochondrion (m) is found, (1 jam), 13, A lysosome-like body including many small vesicles, (lm), 14. A lysosome-like body including several double membranes or myelin-like structure. (1jum), 15, Mitochondria around nucleus [n) showing nuclear pore (arrowhead) and nuclear envelope (ne)(1 zm). 16. A Golgi body. (0.5m). 17, Superficial region where germ disk is not formed. A yolk package composed of large yolk granules (yg), a cup-shaped mitochondrion (m), glycogen granules (arrowhead), and vesicles are exposed directly to perivitelline space (ps). (Jum). Abbreviations: fg: fatty granule, fy; fine yolk granule, gg: glycogen granules; ps: perivitelline space, yg. yolk granule, vm: vitelline membrane, Scale line in parentheses. AN EXPERIMENT ON COLONIZATION OF KARAKURT (LATRODECTUS TREDECIMGUTTATUS, BLACK WIDOW SPIDER) ON ISLAND TERRITORIES IN KAZAKHSTAN CHINGIS K. TARABAEV Tarabaev, C.K, 1993 11 11: An experiment on colonization of karakurt (Latrodectus tredecimguttatus, Black Widow spider) on island territories in Kazakhstan. Memoirs of the Queensland Museum 33(2): 651-652. Brisbane. ISSN 0079-8835. To create an artificial, controllable population of Latrodectus tredecimguttatus (karakurt) with the aim of collecting venom, an experiment on mass colonisation of southern population spiders on an island territory was carried out. Retardation of the overwintering stage under laboratory conditions ensured the availability of large numbers of karakurt for colonisation and eliminated its uncontrollable reproduction in neighbouring territories. Pour créer une population artificiele bien contrélée des Latrodectus tredecimguttatus (karakurt) dans le but d’obtenir du venin on a mis une expérience de la dissémination des Araignées de la population méridionale sur le territoire insulairs. Le delai du stade hivernant dans les conditions de laboratoire assure Ja stabilisation du nombre de masse de karakurt pour leur colonisation et élimine leur reproduction non-contrélée sur les territoires adjacents. (CColonisation, karakurt, egg sacs, Latrodectus. Chingis K. Tarabaev, Institute of Zoology of Kazakhstan National Academy of Sciences, Akademgorodok, 480032 Alma-Ata, Kazakhstan Republic; 19 March, 1993. In Kazakhstan, mass annual collections of venom-producing arachnids are carried out to obtain their venom for medicinal and other pur- poses. Black widow spiders (‘karakurt’, Latrodectus tredecimguttatus (Rossi)) are caught in the greatest numbers. At the same time, their abundance varies from year to year: quite often periods occur during which one can hardly find a single specimen (see Marikovskij, 1956; Levi, 1983; Tarabajev, 1990). A bite from a karakurt is an appreciable danger. Hence, during periods of great abundance, it must be controlled. In connec- tion with this problem, we carried out an experi- ment on karakurt colonisation on an island with the aim of creating an abundant and controllable artificial population. MATERIALS AND METHODS The experiment was performed on the small island ‘Malyj’ (1.4km?) in Alakol’ Lake (46°08’N, 81°52’E) near the northern border of the known karakurt distribution: the 2nd instar spiderlings emerging from egg sacs are often affected here by the late frosts which occur in April-May (Tarabajev, 1990). In contrast, the development of spiders is critically restricted by the shortened warm season: if the postembryos within the egg sacs have no time to develop into the overwintering Ist instar spiderlings, they die during winter (Marikovskij, 1956). This phenomenon stipulated the possibility of creating anumerous, yet controllable karakurt population. To do so we retarded the development of spiderl- ings and then released the 2nd instars over the island. As a result, the spiderlings avoid the dis- astrous late frosts but the postembryos of the new generation in their egg sacs would not have time to develop into overwintering 1st instar spiderl- ings. This phenomenon is therefore the necessary condition for the possibility of creating a control- lable karakurt population, as well as for elimina- tion of uncontrollable mass reproduction of spiders on the neighbouring territories. For the intensification of degree-days deficit effect, the spiderlings from 500 egg sacs of Latrodectus tredecimguttatus collected in Uzbekistan (southern population from Dzhizak Steppe) were used in our experiment. Before the colonisation we made a census of the native population of karakurt on the island. During winter, egg sacs of southern population spiders with overwintering first instar spiderlings were kept in the laboratory (temperature 0-5°C). In the second half of May these were placed into a gauze-covered 20 litre vessel at room tempera- ture (18-22°C), for their reactivation from winter diapause. After moulting in their egg sacs, many spiderlings emerged; then the vessel which con- tained them was placed in a refrigerator (4-S°C) until June. Before mass colonisation, a census of the natural karakurt population on ‘Malyj’ Island was carried out by the visual investigation of the whole island territory fit for the settling by the southern population spiders of karakurt (ca..8500 m*). RESULTS While making a census of the native karakurt population on ‘Malyj* Island before mass colonisation on 12 June 1988, we found one nest from the previous year with two empty egg sacs, and two more old nests, Six living karakurt specimens of 4-Sth instar were also found, By late August there were 3726 nests from the southern population, or one specimen per 2-3m*_ Three females of the native karakurt population were also found: they differed by their larger size (no females were measured). In 28 nests of southern population spiders there was only one egg sac per nest: no €gg sacs were found in the rest, while in three nests of native population spiders. there were two egg sacs in each. Dissection of egg sacs confirmed our views. In four egg sacs of the native karakurt population there were pos- tembryos, in two there were first instar spiderl- ings, while only eggs were found in 20 egg sacs of the southern population. Of 100 nests examined in May 1989, 74 nests were without egg sacs—some nests were ruined; 26 nests each had one egg sac, all eggs were dead, These results confirmed that due to the artificially retarded development of southern population spiders in the northern conditions of Alakol’ Lake the eggs had died within the egg sacs as they had insufficient time to develop to the overwintering first instar spiderlings (the average Alakol’ area temperature in September is no more than 10- 15°C). We therefore propose the following scheme for the creation of many controllable artificial black widow populations for the purpose of obtaining venom, MEMOIRS OF THE QUEENSLAND MUSEUM In August-September, mass collection of females must be carried out. These females are kept in collection boxes for 2-3 weeks until they lay their egg sacs in these boxes. (This phenomenon was first noticed by us when study- ing the technique of mass collecting from the field). Females are subsequently used for obtain- ing venom while egg sacs are kept at room temperature until the Ist instar spiderlings emerge (overwintering stage). After that the egg sacs must be kept in a refrigerator at 0-5°C until the following season. After the reactivation of spiderlings in spring, they are released over the island, which they recolonised effectively. Every August-Septem- ber, mass collection of females is carried out, and. the cycle is renewed. Thus, the indubitable advantage of our method is the elimination of uncontrollable mass reproduction of karakurt and the absence of any necessity of special egg sacs collecting for colonisation, LITERATURE CITED LEVI, H.W. 1983. On the value of genitalic structures and coloration in separating species of widow Spiders (Latrodectus sp.) (Arachnida: Arancae: Theridiidae). Verhandlungen des Naturwis- senschafilichen Vereins zu Hamburg (NF) 26; 195- 200, MARIKOVSKI, P.I. 1956, [Tarantula and karakurt: morphology, biology, toxicity). (Kirghiz SSR Academy of Sciences Publishers: Prinze.). [in Russian] TARABAJEY, CH. 1990, Winter frosts and late frosts as the reason of karakurt (Black Widow Spider, Latredectus tredecimguitatus) depression in Kazakhstan, Bulletin de la Societe Enropeenne d' Arachnologie (Comptes Rendus du X1""* Col- logue Europeen d’Arachnologie, Paris (France), 2-4 juillet 1990), No. hors sere L: 346- 348. DISTRIBUTION OF LATRODECTUS (THERIDIDAE), ERESUS AND STEGODYPHUS (ERESIDAE) IN KAZAKHSTAN AND CENTRAL ASIA CHINGIS K. TARABAEV, ALEXEY A. ZYUZIN AND ANDREY A. FYODOROV Tarabaev, C.K., Zyuzin, A.A. and Fyodorov, A.A. 1993 11 11: Distribution of Latrodectus (Theridiidae), Eresus and Stegodyphus (Eresidae) in Kazakhstan and Central Asia. Memoirs of the Queensland Museum 33(2): 653-657. Brisbane. ISSN 0079-8835. The distributions of three Latrodectus species (L. tredecimguttatus, L. dahli and L. pallidus), and of three eresid species (Eresus niger, E. tristis and Stegodyphus lineatus) within the Kazakhstan-Central Asian region are analysed based on the literature and on original data. Latrodectus tredecimguttatus presumably occupies almost the entire Kazakhstan territory, while two other widow species are local and more southern: both of them are first recorded here within Kazakhstan. Preliminary morphological and mating analyses show that both ‘Latrodectus tredecimguttatus’ and ‘Eresus niger’ within the territory of Kazakhstan and Central Asia are composite species: the first consists of at least one species different from the European L. tredecimguttatus, and the second consists of at least three separate species. On a analysé la distribution de trois espéces du genre Latrodectus (L. tredecimguttatus, L. dahli et L, pallidus) et de trois espéces de la famille Eresidae (Eresus niger, E. tristis et Stegodyphus lineatus) dans la région du Kazakhstan et de |’ Asie centrale d’aprés le données littéraires et originales. L’aire d’habitation de Latrodectus tredecimguttatus comprend, hypothétiquement, presque tout le territorie du Kazakhstan, tandis que deux autres espéces sont locales et plus méridionales: l'une et l’autre sont mentionnées ici pour la premiére fois pour Kazakhstan. L’analyse morphologique préalable et les expériences d’accouplement montrent que Latrodectus tredecimguttatus aussi bien que Eresus niger au Kazakhstan et a I’ Asie Centrale sont des espéces collectives: dont la premiére se compose, au moins, d’une espéce différente de L. tredecimguttatus d'Europe et |’autre se compose, au moins, des trois espéces séparées.)Latrodectus, Eresus, Stegodyphus, distribution. Chingis K. Tarabaev, Alexey A. Zyuzin, Andrey A. Fyodorov, Institute of Zoology, Kazakhstan National Academy of Sciences, Akademgorodok, 480032 Alma-Ata, Kazakhstan Republic; 19 March, 1993. The genus Latrodectus (Theridiidae) and the family Eresidae have not been studied very much in Central Asia. Before 1950 only one Latrodec- tus species was known from the former territory of the U.S.S.R.-L. tredecimguttatus (Rossi), or ‘karakurt’. Two years later, Spassky (1952) first reported L. pallidus O. Pickard-Cambridge from the western, desert regions of the Turanian zoogeographic province [=Turkmenistan ter- ritory]. Later Charitonov (1954) described the new subspecies L. pallidus pavlovskii from Turk- menistan (the so-called ‘white karakurt’). Twen- ty years later Tystshenko and Ergashev (1974) found in Uzbekistan another black widow species, L. dahli Levi. Amongst the Eresidae, three species have previously been recorded: Eresus niger (Petagna), E. tristis Kroneberg and Stegodyphus lineatus (Latreille). This paper deals with new collections and data relating to the two groups and species distributions. Also, we suggest that previous broad species concepts, especially within L. tredecimguttatusand E. niger, must be revised. MATERIALS AND METHODS This work is based on material collected mainly by us in Kazakhstan and Central Asia. Our spec- imens were compared with those from Europe and North Africa. Spiders were examined in 70% alcohol using binocular microscopes MBS-1 and MBS-10. Preliminary experiments on mating be- tween European L. tredecimguttatus and Widows from Kazakhstan were also carried out. Abbreviations: BIN, Biological Institute, Nov- osibirsk, Russia; IZA, Institute of Zoology, Alma-Ata; MCZ, Museum of Comparative Zool- ogy, Cambridge, Massachusetts, USA; MNHN, Muséum National d’Histoire Naturelle, Paris, France; ZISP, Zoological Institute, St. Peters- burg; ZMMU, Zoological Museum of the Mos- cow University. 654 yXS MEMOIRS OF THE QUEENSLAND MUSEUM ent 3 feo CRONIN AEN 40" Olas: Bn RRR Se COL *, x <> XO >i: ; re ee, 35° 35 *, eteee 554 60° Fad 65° 709 752 Ae FIG, |: Distribution of Larrodectus. spp. in Kazakhstan and other Central Asian Republics. Legend: O= L. tredecimguitatus;, = L. dahli, O=L. pallidus pavlovskii; oblique hatching = distribution of L. tredecimguttatus after Marikovskij (1956); cross hatching = suggested distribution of L, pallidus within the distribution of L. tredecimgurtarus, Black figures = published data; white figures = original data. RESULTS AND DISCUSSION FAMILY THERIDIIDAE Latrodectus Walckenaer REMARKS The northern border of the widow spiders’ dis- tribution within the former USSR seems to pass near 52°N (Fig. 1). Latrodectus tredecimguttatus (Rossi) “Karakurt’ REMARKS Within the former USSR this species has been known under the names L. conglobatus C.L, Koch, L. erebus Savigny and Audouin, L. lug- ubris Motchoulsky, £. tredecimgutiatus var. lug- ubris (Dufour), etc. (Charitonoy, 1932). Rossi- kov (1904) devoted a monograph to this species and Marikovskij (1956) analysed the biology and distribution of L, tredecimguttatus within the former USSR. According to this author, karakurts are found over almost all of Kazakhstan (Fig. 1), However, existing difficulties in the systematics of Latrodectus species (see Levi, 1983), as arule. result in too wide an interpretation of their dis- tribution. When investigating Latrodectus species, we found that adult females of L. tredecimguttatus from Italy had a light spotted abdomen while Kazakhstan specimens were completely black. Dr G. Schmidt (pers. comm.) considers the karakurt from Kazakhstan to be the species Latrodectus lugubris (Dufour) described from Egypt. Preliminary experiments on mating carried out in 1991 together with Mr D. Weick- mann-Zwoerner (Germany) showed that LATRODECTUS, ERESUS, AND STEGODYPHUS IN KAZAKHSTAN Kazakhstan specimens could not cross with European £, tredecimguttatus (two males. from Kazakhstan were used). At present the distribution of L. rredecimgui- tatus as delimited by Marikovskij (1956) must be revised, as we now suppose the traditional ‘L. tredecimguitatus’ in Kazakhstan to be a separate species. MaTeriAL EXAMINED Italy: 3 2, Lazio, near Priverno, 16 May 1962, fields and stones, H. Levi (MCZ). Kazakhstan and Central Asia: many males and females from different localities (IZA). Latrodectus dahli Levi REMARKS This very localised species among the Central Asian cepublics occurs in Uzbekistan only (Tystshenko & Ergashev, 1974; Ergashev, 1990); in Kazakhstan, it was found by us first in the Kyzylkum Desert (two females, det. Dr Y.M. Marusik)(Fig. |). We have compared our specimens with the female paratype of L. dafhili from Iran. and found their resemblance in the hairiness of the abdomen’s dorsum (long slender spines and rather long setae between them: see also Tystshenko and Ergashev, 1974, fig. 3). Nevertheless, the epigynal openmg in ali our specimens is 4 limes as wide as long, while in the female paratype it is only 3.4 times as wide as long: slight differences are also in the vulvae (cf. Levi, 1959, figs 11, 12; Tystshenko and Er- gashev, 1974, figs 4, 5). As the male of £. dahli from the type locality is up to now undescribed, we cannot be sure that our specimens belong to real L. dahl. MATERIAL ExaMINED Iran: | paratype ¥, Bushire, Persian Gulf (MCZ). Uzbekistan: 1 d,1 2, Kashkadarja Area, Karshi Steppe, N.E. Ergashey. Kazakhstan: 2 9, South Kazakhstan Area, Kyzylkum Desert, 77,.5k NW of Chardara Vill., 5-6 Jun 1989, Tarabaev, Fyodoroy, Zyuzin (IZA). Latrodectus pallidus pavloyskit Charitonov (Fig. 1) REMARKS Within Kazakhstan, it was found by us first in the Kyzylkum desert, which is probably its north- ermmost limit. To clarify the taxonomic position of L, pallidus pavlovskii, thorough comparison of 635 our spiders with the type material or topotypes of L. pallidus is necessary. MarTertaL EXAMINED Turkmenistan: 12, Tashauz Area, Shakh- senem, under Artenusia, 9 Oct 1983, O.S. Soyunov. Uzbekistan: 4 2, Dzhizak Area, ‘Kyzylkum’ state farm, 16 Jul 1982, N.E. Er- gashev. Kazakhstan: 192, South Kazakhstan Area, Kyzylkum Desert near Tabakbulak Vill., 24 Aug 1991, A.A. Zyuzin, B,M, Gubin (1 ¢, 2 ? of Tabakbulak population in laboratory) (IZA). FAMILY ERESIDAE Eresus Walckenaer Eresus niger (Petagna) REMARKS Published and original data on the distribution of this species within the Sibero-Kazakhstan- Central Asian region, in the European part of Russia (see Charitonoy, 1932) and in Europe (sec Bonnet, 1956) show that the northern limit of ats area seems to pass near 56°N: thus, E. niger is theoretically distributed over the whole Kazakhstan and the Central Asian region. Preliminary analysis of material we have at our disposal show that at least three separate specics of the ‘Eresus niger complex occur in Kazakhsian (Fig. 2). The acute deficit uf specimens of both sexes taken from the same pine is the main obstacle to a detailed taxonomic study. According to Merrett and Millidge (1992), the correct name for the species Eresus niger (Petag- na) is Eresus cinnaberinuy (Olivier) (see also Lehtinen, 1967, p. 233). MATERIAL EXAMINED France: 2 6,2 2 2 juy., Col du Ceris, 15 Sep 1908; Banyuls, 31 May 1909 (MNHN, No. AR 838). Spain: 3 ¢, 4 2, La Granja, Jun 1908 (MNHN, No. AR 837). Mongolia: | d, ‘Potanin, Schenkel det. 1946" (MNHN, No, AR 852), Hun- gary: 1 6, Csdkberény, Vertes, 20 Sep 1991_V.V. Dubatolov, V.G. Mordkovitch. Russia: 3 ¢, Bashkir Reserve, Bashart, 1.V. Stebaev; 1 3, Novosibirsk Area, 13k W of Karasuk Vill., 7 Sep 1989; 5 d, ibidem, 27k SE of Zdvinsk Vill, Malyje Chany Lake, 10 Sep 1989, V,P. Pekin. Turkmenistan: | ¢, Kopetdag Reserve, 15 May 1988, Karpenko; 2 d, 25 Aug 1988, ibidem, 1Sk W of Firyuza Vill., Mount Dushak, 2100 m; 1 2, 656 957 MEMOIRS OF THE QUEENSLAND MUSEUM TOS 75° 50° FIG, 2: Distribution of eresid spiders in Kazakhstan and other Central Asian Republics. Legend: O= ‘Eresus niger’ complex: 1, 2,3, = E. sp. 1, 2, 3 (see text); O=E. tristis; C= Stegodyphus lineatus. Black figures = published data; white figures = original data. ibidem, Firyuza Vill., 3 Apr 1991, V.V. Dubatoloy, V.K. Zinchenko: 1 ¢, Kugitang Range, 5k SE of Bazar Depe Vill., 13-19 May 1991, V.V. Dubatolov (all BIN). Kazakhstan: numerous 6d 29 from different parts of Kazakhstan (see Fig. 2) (IZA). Eresus tristis Kroneberg REMARKS According to published data, this species was previously found only in southem and South- Eastern Kazakhstan (Kroneberg, 1875; Spassky and Shnitnikov, 1937); beyond the borders of the former USSR, E. tristis was found only in China by G.N. Potanin’s expedition: see Simon (1895), ‘la riv. Sotschshan au N. de Ja chaine du Tjan- Shan’. [Charitonov (1932) wrongly placed this site within the former USSR territory]. Males of E. tristis can be readily separated from those of E. niger by the black colour of their abdomen and legs (as in E. niger females), some- times with white markings. Despite this very distinctive feature, E. tristis was recently synonymised with E. niger based on the similarity of their genitalia (see Nenilin and Pes- tova, 1986). However, our preliminary data showed sufficient differences of E. tristis from all of our ‘red’ males in the fine structure of the male palp; at the same time, black males from different parts of Kazakhstan and Central Asia have very similar palp structure. The main taxonomic prob- lem is that the female of this species is up to now unknown. MATERIAL EXAMINED Kazakhstan: 1 ¢ holotype, South Kazakhstan Area, ‘Syrdarja, the end of April’, A.P. Fedtschenko’s Turkestan Scientific Expedition by the Natural History Amateurs’ Society (ZMMU No. Ta 1104); 1 d, Alma-Ata Area, 5k NE of Kapchagaj City, A.A. Fyodorov (IZA). LATRODECTUS, ERESUS, AND STEGODYPHUS IN KAZAKHSTAN 65 Turkemistan: 3 d, Western Kopetdag Ridge, near Kara-Kala Vill., 7 Feb 1979, I. Morozova (ZISP). Tadzhikistan: 1 ¢, ‘turn to Chashma, 9.V.1986, Itka’ (BIN). Stegodyphus Simon Stegodyphus lineatus (Latreille) (=Eresus arenarius Kroneberg) REMARKS This. species was previously known from Turkmenistan, Uzbekistan and Southern Kazakhstan. We have found it considerably northwards and eastwards (Fig. 2). MATERIAL EXAMINED Many males and females from: Spain; Italy (Sicily); Algeria; Tunisia (Kairouan) (MNHN No. AR 785, 786); different parts of Kazakhstan and Centra! Asian republics (see Fig. 2) (IZA). ACKNOWLEDGEMENTS For placing the necessary material at our dis- posal and for assistance in experiments we are grateful to: Prof. H.W. Levi (Cambridge, Mas- sachusetts, USA), Drs D.V. Logunoy, V.V. Dubatoloy (Novosibirsk), K.G. Mikhailov (Mos- cow), V.I. Ovtsharenko (St. Petersburg) (all Rus- sia), Ch. Rollard (Paris, France), and Mr D. Weickmann-Zwoerner (Weissenburg, Ger- many). LITERATURE CITED BONNET, P. 1956. ‘Bibliographia Araneorum’, vol, 2(2): 919-1026. (Douladoure: Toulouse). CHARITONOV, D.E. 1932, Katalog der Russischen Spinnen. Annuaire du Musée Zoologique, Leningrad 32 (Beilage): 1-206. 1954. [The new representative of the genus Latradectus from Turkmenia (Lafrodectus pal- lidus O.P. Cambr, subsp. pavlovskii n.)). Zoologicheskij Zhurnal 33: 480-485, [in Rus- sian] ERGASHBEY, N.E. 1990, [“Ecology of the venomous =I spiders in Uzbekistan’). (‘Fan’ Publishers: Tash- kent). [in Russian] KRONEBERG, A. 1875. Araneae. In: Fedtschenko, A.P., ‘Reise in Turkestan, Zoologischer Theil’, vol, 2; 1-58. Moscow: LEHTINEN, P.T. 1967. Classification of the cribellate spiders and some allied families, with notes on the evolution of the suborder Araneomorpha. Annales Zoologici Fennici 4: 199-430, LEV], H.W. 1959. The spider genus Latrodectus (Araneae, Theridiidae). Transactions of the American Microscopical Society 28; 7-43, 1983. On the value of genitalic structures and coloration in separating species of widow spiders (Latrodecms: sp.) (Arachnida: Araneae: Theridiidae). Verhandlungen des Naturwis- senschafiliches Vereins zu Hamburg, (NF) 26: 195-200. MARIKOVSKIU, P.l. 1956. [Tarantula and karakurt: morphology, biology, toxicity’), (Kirghiz SSR Academy of Sciences Publishers: Frunze). [in Russian] MERRETT, P. & MILLIDGE, A,F. 1992. Amendments to the check list of British spiders. Bulletin of the British Arachnological Society 9: 4-9. NENILIN, A.B, & PESTOVA, M.V. !986.|The spiders of the family Ercsidae in the USSR fauna]. Zoologicheskij Zhurnal 65; 1734-1736, [in Rus- sian] ROSSIKOY,, K.N. 1904. [The venomous spider karakuri], Agricultural monograph, Trudy Byuro po Entomologii 5 (2): 1-232. St. Petersburg. [in Russian] SIMON, E. 1895, Arachnides tecueillis par Mr G. Potanine en Chine et en Mongolie (1876-1879), Bulletin de ! Académie Impéniale des Sciences de St. Petersburg, (5) 2 (4): 331-345. SPASSKY, S.A, 1952. [The spiders of the Turamian zoogeographic province]. Entomologicheskaje Obozrenije 32: 192-205. [in Russian] SPASSKY, S.A. & SHNITNIKOY, V,N. 1937. [Materials on the spider fauna of Kazakhstan]. Trudy Kazakhstanskogo Filiala AN SSSR 2: 265- 300, [in Russian] TYSTSHENKO, V.P. & ERGASHEV, N. 1974. [Latrodectus dahli Levi (Aranci, Theridiidae), a species of venomous spiders new in the USSR fauna]. Entomologicheskoje Obozrenije 53: 933- 937. [in Russian]. GEOGRAPHIC VARIATION OF THE NUMBER OF B-CHROMOSOMES IN METAGAGRELLA TENUIPES (OPILIONES, PHALANGIIDAE, GAGRELLINAE) N. TSURUSAKI Tsurusaki, N. 1993 11 11; Geographic variation of the number of B-chromosomes in Metagagrella tenuipes (Qpiliones, Phalangiidae, Gagrellinae). Memoirs of the Queensland Museum 33(2); 659-665, Brisbane. ISSN 0079-8835. Chromosomes of Meragagrella tenuipes (L. Koch) (Arachnida, Opiliones,, Phalangiidae, Gagrellinae) were surveyed in 8 populations in Japan. Almost every individual examined had one or more (highest number per cell was 19) supernumerary or B-chromosomes, in addition to the basic set of chromosomes (2n=18). These B-chromosomes are heterochromatic, and during meiosis they appeat to behave as univalenis. The number of B-chromosomes varied both among, and within populations. The number also fluctuated to some extent among cells from the same individual, suggesting nondisjunction at mitotic anaphases, No correlation could be elucidated between the number of B-chromosomes and external morphologies or habitat type. The number of B-chromosomes may affect growth tate, and in tam reduce the synchrony of breeding within a population. Die Chromosomen von Melayagrella tenuipes (L. Koch) (Arachnida, Opiliones, Phalan- giidae, Gagrellinac) wurden in 8 japanischen Populationen untersucht. Fast jedes iiberpriifte Individuum wies eines oder mehrere (die hoéchste Anzahl pro Zelle war 19) iberzahlige oder B-Chromosomen zusatzlich zum Standardchromosomensatz (2n = 18) auf, Diese B- Chromosomien sind heterochromatisch und scheinen sich wihrend der Meiose als Univalente zu verhalten. Die Zahl der B-Chromosomen variiert sowohl zwischen als auch innerhalb von Populationen, Sie schwankt in gewissem Ausmaf auch zwischen Zellen aus em und demselben Individuum, was avf Non-Disjunction bei mitotischen Anaphasén schlieBen 1ABt. Zwischen der Anzahl der B-Chromosomen und der duBberen Morphologie oder Habitaitypen konnten keine Korrelationen gefunden werden, Es besteht die Moglichkeit, daB die Zahl der B-Chromosomen die Wachstumsrate beeinflussen und in der Folge die Synehronie der Fortpflanzung innerhalb ciner Population reduzieren kann.[|Opiliones, Metagagrella lenuipes, Japan, B-chromosomes, geographic variation. Nobuo Tsurusaki, Department of Biology, Faculty of Education, Tottori University, Tottori 680, Japan; 29 October, 1992. MATERIALS AND METHODS The harvestman Metagagrella tenuipes (L., Koch) is widespread throughout Japan but with a peculiar habitat and distribution pattern. In southern Japan, this opilionid is typically coastal. However, in northern Japan, it also occurs inland und prefers open habitats,.e.g. parks and gardens, that are affected by moderate human disturbance. During a chromosomal survey of this species, the number of chromosomes varied both within and among populations, with a range of 2n=18 to 36, Moreover. the number of chromosomes vaned somewhat from one cell to another in almost all individuals. Close examination of mitotic and meiotic chromosomes revealed that the karyotype of this species is usually composed of 2n=15 standard chromosomes and one or more supemumerary or B-chromosomes, and that the latter cause the overall chromosome number to vary. Here, I will describe the karyotype, nature of the B-chromosomes, and pattern of geographic yunation in the B-chromosome number, The specimens used for chromosome examins- tion are listed (Table 1, Fig. 1). Cytological data were obtained from ait-dried preparations of tes- tes or ovaries of field-collected adults and penul- limates. The technique used is described in Tsurusaki (1985) and Tsurusaki and Cokendol- pher (1990). In some cells, pattems similar tu C-bands were observed despite the fact that these cells had received no special treatment. In many individuals the number of B-chromosomes varied from cell to cell, In such cases. the chromosome number of each is represented by a modal num- ber. For two populations (Nakajima and Marmyama), lengths of fernur I of the specimens used in the chromosome preparation were measured with an eyepiece graticule. Detailed collection data on the specimens ex- amined are listed in the appendix. 660 Shirahama 1406 F = 4-11 (6.6) Nakajima 2674 F | 0-3 (1.7) Campus of Hokkaido Univ. MEMOIRS OF THE QUEENSLAND MUSEUM Wakasakanai aml 18 \ 17:6 Maruyama 2073 $ : 3-15 (7.0) ay Sunagawa 3d : 2-6 (4.7) Botanical Garden 641 $ ! 3-10 (6.2) ,, %0 Awa-Amatsu 13m : 1-6 (3.5) FIG. |. Map of populations of M. renuipes, Japan, used here (double open circles) with records compiled from literature (e.g. Suzuki, 1973; Suzuki and Tsurusaki, 1983) and data in the appendix (solid circles), No. of samples and range of B-chromosome number in each study population are shown, with means in parentheses. RESULTS KARYOTYPES AND NATURE OF B-CHROMOSOMES The chromosome number of this species varied enormously among and within populations. From comparisons of the karyotypes of individuals with the lowest chromosome number, 2n=18, to those from others with 2n=19 and greater, and from analyses of both meiotic chromosomes and unintentionally obtained C-banded chromosomal spreads, the chromosome number of the standard karyotype, which consists of so-called A-chrom- osomes alone, was determined to be 2n=18 for both males and females (Figs 2-3). 1. Standard karyotype (Fig. 3) Autosomes consist of 8 pairs of medium-sized metacentrics (Nos. 4 and 5), submetacentrics (Nos. 1, 3, 7, 8), and subtelocentrics (Nos. 2 and 6). The X chromosome, the largest, is sub- telocentric, while Y is submetacentric and similar in size to chromosome No. 1, In C-banded mitotic metaphases, centromeric regions of the A- chromosomes were positively stained (Figs 4-5). No prominent differences were found among the TABLE 1. B-chromosome numbers in 8 populations of Meragagrella tenuipes. NOTES: ' S = seashore habitats, 1 =inland habitats e.g. parks, fields; by mode of each individual; Calculated only for samples with >5 individuals; Range, mean and mode not for all cells counted but for values represented One or more were juveniles, Locality and habitat type in parentheses! Date Number of B-chromosomes~ 9-1X-1985 Wakasakanai (5) Sunagawa (I) Campus of Hokknido Univ. (U) as above, 1986 (I) [8-VII1 & 9-IX-1986 |8d,2 2 5-IX-1986 27-VIIL-1984 29-VII-1983 Maru amd, Sapporo (1) Awa-Amatsu (S) Shirahama (S) oom Ce Siete) FT Ce ( Notaina(§) ae vuresis os '¢9 Jo [3 i? ua] 1,02 B-CHROMOSOMES IN METAGAGRELLA TENUIPES ? ~e. *. os ett Re 4 tac ign so we ’ « “es . . a t?* te . wt* my ain * ve ovat ¢ ¢ "fo** c ~~) FIG, 2. Representative chromosome complements at spermatogonial mitotic metaphase of male Metagagrellatenuipes, A, Nakajima, 2n=18 (18's); B, Maruyama, 2n=28 (18A's + 10B's); C, campus of Hokkaido Univ., 2n=37 (18A’s + 19B's). Scale = Spm. standard karyotypes of individuals from various populations. 2. B-chromosomes Tn addition to a set of standard chromosomes described above, almost all chromosomal spreads contained at least one B-chromosome. These were meta- or submetacentric, equal to or smaller than the shortest pairs (No. 8) of the A-comple- ment (Fig. 3). In C-banded chromosome spreads, the B's were heteropycnotic, darkly staining along their total lengths (Figs 4-5). During meiosis, the B’s remained univalent (Fig. 4-5) even when the cell carried 2 or more. The number of B’s varied considerably from one cell to the other within a single individual, possibly due to nondisjunction at anaphase during mitosis. Numeric variation in B’s among individuals within populations was also evident (Fig. 6). No significant differences were found in the number of B’s between the sexes from any population (Mann-Whitney U-tests for each of four popula- tions where both sexes were sampled, P=().48- 0.96). GEOGRAPHIC VARIATION IN NUMBER OF Brs The number of B-chromosomes varied siz- nificantly among populations (single classifica- tion ANOVA: F=34.6; d.f£.=7; P<0.001) (Figs 1 and 6, Table 1). The lowest and the highest population means of the number of B’s were 1.7 for Nakajima (n=30) and 18 for the campus. of Hokkaido University (n=1), respectively, and the means of the other populations lay between the two extremes, range = 3.5-7. However, no sig- nificant correlations could be detected between the number of B’s and characteristics such as 661 Rieletis sere onary * Y o BR O8 O8 8G aE de io an fF Batter see 2n=18+108's AOA 1A TE ke fa ne ba he HSZHRERAFAS PH wEGAS,. 2n={8+196's FIG, 3. Karyolypes of male Méragagrella tenuipes based on the photographs in Fig. 2. A, Nakajima, B- Maruyama; C. campus of Hokkaido Univ. B- chromosomes are arranged on the second row in B and C. Scale = 5jum. latitude (Spearmann’ s coefficient of rank correla- tion, rs=0.19, n=8, P>0.05) and habitat types (seashore or inland: Mann-Whitney U-test. P>0.05). DISCUSSION CHARACTERISTICS OF THE B-CHROMOSOMES According to Jones and Rees (1982), B- chromosomes have been reported in over 1000 species of plants and more than 260 species of animals. In Arachnida, however, only three species of Acari have been shown to have B's: Aponomma fimbriatum and two species of Haemaphysalis (Oliver and Bremner, 1968; Oliver et al., 1974). The B-chromosomes in Metagagrella tenuipes have the following characteristics that are typical for B’s recorded in various other organisms (White, 1973: Jones and Rees, 1982; Werren ef al,, 1988; Shaw and Hewitt, 1990; Jones, 1991): (i) they are smaller than most members of the A-complement; (2) they appear to be comprised of a large amount of constitulive heterochromatin; (3) they remain univalent during meiosis; (4) the number of B's varies from one cell to another even within an individual, indicating they display nondisjunction at anaphases of spermatogonial mitoses. However, the frequency and the number of B's were rather unusual. In this species, every popula- tion sampled contained B’s and the frequency within a population was up to 87% in Nakajima and 100% inthe other 7 populations, The number of B’s retained per individual of this species was also extraordinarily high; the population means had arange from 3.5 to 7 in 6 out of 8 populations 662 £ 5 " /. > FIG. 4. C-banded mitotic metaphase (A) and meiotic metaphase I (B) in d M. tenuipes from Sunagawa, with 2 B-chromosomes (arrowed). Scale = 5m. (Table 1). The higher end was found in the single male sampled from the campus of Hokkaido University, whose modal number of 18 B’s was exhibited by 30 cells and the maximum number of 19 in 3 cells (Figs 2-3). These are among the highest numbers of B’s in animal species so far recorded, close to the number ‘about 20’ in Xylota nemorum (Diptera: Syrphidae) (Boyes and Van Brink, 1967). EFFECT OF B's ON PHENOTYPE Metagagrella tenuipes shows marked variation both among and within populations in external morphology, such as body size, leg lengths, de- gree of development of a spine on the dorsal scutum, number of noduli on the legs, and colora- tion of the body (Suzuki, 1973; Suzuki and Tsurusaki, 1983). However, no correlation was found between these characters and the number of B-chromosomes (Fig. 7). These facts are con- sistent with the observation that the B’s are C- band positive. If these B’s are indeed genetically inactive, numerical variation of B’s would lead to no effect on the phenotype of their owner. Although few studies have demonstrated any MEMOIRS OF THE QUEENSLAND MUSEUM = «8 FIG. 5. C-banded mitotic metaphase (A) and diakinesis - metaphase 1(B)in d M. tenuipes from Maruyama, with 6 B-chromosomes (arrowed). Note: 9 bivalents formed by 9 pairs of A-complement of chromosomes. Scale = 5m. exophenotypic effect due to B’s, some show a relationship between the number of B- chromosomes and the rate of development (Hewitt and East, 1978; Harvey and Hewitt, 1979). Thus, there is a possibility that the presence of B-chromosomes retards the cell cycle due to the additional DNA or its organization which is possibly different from A- chromosomes. In turn, these effects may in- fluence the growth and development of the whole organism (Jones and Rees, 1982). Such influen- ces might be related to an unusual feature of the life history of this species, namely, high variability among individuals in the time to reach maturity. The duration of coexistence of juveniles and adults of this species at Maruyama is es- timated to be about three weeks, whereas it is less than 1-2 weeks in other species of opilionids having no B-chromosomes, such as Oligolophus aspersus, Leiobunum japonicum, and two species of Nelima from the same locality (Tsurusaki, B-CHROMOSOMES IN METAGAGRELLA TENUIPES 40 Botanical Garden 1982 50114 X=6.2 20 = Botanical Garden 1986 = 20 Br24 “= X=6.2 5 =} Maruyama 200° 3 $ = 20 X-7.0 — au 40 Awa-Amatsu 1307 Shirahama 14076 $ X=6,6 Nakajima 26074 R=17 3°94 5 & 7 & 9 10 11 12 13 14 15 Number of B-chromosomes FIG, 6. Frequency distribution of B-chromosome num- bers in 6 samples from 5 populations, The other 3 populations (Wakasakanai, Sunagawa, and campus of Hokkaido Univ.) omitted due to paucity of specimens suryeyed. unpublished data based on weekly field-collec- hons made in 1979). The same phenomenon is also inferred from field-data from various localities all over Japan. This versatility in the timing of final molting of this species might be ascribed to the numerical variation of B- chromosomes, Further study is needed, GEOGRAPHIC VARIATION IN NUMBER OF B's The fact that the B’s are found in every popula- lion over a wide geographic range of this species indicates that they are of rather ancient origin. Marked morphological variation among the B- chromosomes also aitests to their long evolution- ary history. However, it is also possible that they might be produced de nove from the A-comple- ment by recurring mutation. Although B’s appear widespread across the species range, the number of B’s considerably varied among populations, with a fairly wide range from 1.7 at Nakajima to 18 on the campus of Hokkaido University, In each population, the number of B’s may be stable for at least several years; there was no significant difference in their 663 ‘ * Nakajima 8 * ® Maruyama Length of femur | (mm) 0 2 Number of B-chromosomes 4 6 8 10 12 FIG. 7, Relation of length of femur 1 to number of B-chromosomes in 2 populations (Nakajima and Maruyama) of M, /enuipes, No significant correlation between 2 variables in cach population [r = 0.305 (P>0.1) far Nakajima; r = 0.065 (P>0.1) for Maruyama], although both characters show prominent differences between two populations. Two variables may be negatively correlated (although spuriously) between populations. Leg lengths decrease with increase in latitude (Tsurusaki, un- publ.) but the number of B’s does not. frequencies in the Botanical Garden at Sapporo which were sampled in 1982 and 1986 (Fig. 6). If B-chromosomes were inherited in a non-Men- delian manner, and were neutral in phenotypic expression, the frequency of B's would not be stable. For example, it might be expected that the crossing of a male with 3 B's and a female with 3 B's would produce some offspring with 4 or more B’s. However, no individuals with more than 3 B’s are found in Nakajima population, This indicates thal some selection pressure limits the number of B’s that one individual can retain in a particular population. It is. still uncertain what factors determine the population mean and the range of the number of B's. However, this species may be useful! in studying various aspects of B’s and ‘selfish’ DNA, including the controversial issues on the level of selection discussed by Wer- ren et al., (1988) and Shaw and Hewitt (1990). ACKNOWLEDGEMENTS 1 would like to thank Dr. R.G. Holmberg, of Athabasca University, Alberta, and two anonymous referees for useful comments and careful reviews that improved the manuscript. An abstract in German was kindly prepared by Dr. J 664 Gruber of Naturhistorisches Museum Wien. Late Dr. T. Ito and the staff of the Seto Marine Biologi- cal Laboratory, Kyoto Univ. and Dr. S. Otsuka, Hiroshima Univ., provided facilities for chromosome preparation of the Shirahama population. The following persons kindly provided material used to map the range of Metagagrella tenuipes: Drs. Sk. Yamane (Kagoshima), A. Otaka (Hirosaki), N. Yoshida (Sapporo), Ms. T. Sato (Tokyo), and Messrs. T. Kuwahara (Wakkanai), T. Tanabe (Tokushima), K. Ishii (Gumma), H. Okada (Himeji), Y. Nishikawa (Osaka), N. Nunomura (Toyama), M. Yamashita (Iki). This work was partly supported by Grants-in-Aid nos. 63740434, 02854100, and 03740393 from the Ministry of Education, Science and Culture, Japan. LITERATURE CITED BOYES, J.W. & VAN BRINK, J.M. 1967. Chromosomes of Syrphidae III. Karyotypes of some species in the tribes Milesiini and Myolep- tini. Chromosoma 22: 417-455. HARVEY, A.W. & HEWITT, G.M. 1979. B- chromosomes slow development in a grasshop- per. Heredity 42: 397-401. HEWITT, G.M. & EAST, T.M. 1978. Effects of B chromosomes on development in grasshopper embryos. Heredity 41: 347-356. JONES, R.N. 1991. B-chromosome drive. American Naturalist 137: 430-442. JONES, R.N. & REES, H. 1982. ‘B Chromosomes’. (Academic Press: London). OLIVER, J.H. & BREMNER, K.C. 1968. Cytogenetics MEMOIRS OF THE QUEENSLAND MUSEUM of ticks. ITI, Chromosomes and sex determination in some Australian ticks (Ixodoidea). Annals of the Entomological Society of America 61: 837- 844. OLIVER, J.H., TANAKA, K. & SAWADA, M. 1974. Cytogenetics of ticks (Acari: Ixodidae) 14. Chromosomes of nine species of Asian Haemaphysalines. Chromosoma 45: 445-456. SHAW, M.W. & HEWITT, G.M. 1990. B- chromosomes, selfish DNA and theoretical models: where next? 197-223. In Futuyma, D.J. and Antonovics, J. (eds). “Oxford Surveys in Evolutionary Biology, Vol. 7’. (Oxford Univer- sity Press: New York). SUZUKI, S. 1973. Opiliones from the South-west Is- lands, Japan. Journal of Science of the Hiroshima University, Ser. B, Div. 1 (Zoology) 24: 205-279. SUZUKI, S. & TSURUSAKI, N. 1983. Opilionid fauna of Hokkaido and its adjacent areas. Journal of the Faculty of Science, Hokkaido University, Ser. VI, Zoology 23: 195-243. TSURUSAKI, N. 1985. Taxonomic revision of the Leiobunum curvipalpe-group (Arachnida, Opiliones, Phalangiidae). I. hikocola-, hiasai-, kohyai-, and platypenis-subgroups. Journal of the Faculty of Science, Hokkaido University, Ser. VI, Zoology 24: 1-42. TSURUSAKI, N. & COKENDOLPHER, J.C. 1990. Chromosomes of sixteen species of harvestmen (Arachnida, Opiliones, Caddidae and Phalan- glidae). Journal of Arachnology 18: 151-166. WERREN, J.H., NUR, U., & WU, C.-J. 1988. Selfish genetic elements. Trends in Ecology and Evolu- tion 3: 297-302. WHITE, M.J.D. 1973. ‘Animal Cytology and Evolu- tion, 3rd ed.’. (Cambridge University Press: Cambridge). B-CHROMOSOMES IN METAGAGRELLA TENUIPES 665 APPENDIX. New material of M. tenuipes used in Fig. 1. Data in order: locality, altitude if available and needed, no, individuals, no. specimens dissected in parentheses if needed (Value may not be. as in Table 1, since no countable chromosomal spreads were obtained for some specimens), date collected, collector (NT = N. Tsurusaki; YN=Y. Nishikawa). HOKKAIDO; I. Rebun, Kabukai, Kabukai Elementary School, 10m, 1 juv., 1 1-vin-1990, yn. 1, Rishiri: Oshidomari, ca. 20m, 1 d, 8-vm-1985, Y. Kuwahara; Oshidomari, 5m, | 2, 2 juv., 7-9-vii-1990. 5. Ueno, M. Sato, yn; Fujino, 10m, 1 juv., 7-vin-1985, wr. Wakkanai: Soya Point, Im, 2 d,3 9,1 juv., 2-1x-1988, nr; Wakkanai Port, 2m, 4 9, 5 juv., 7-vin-1985, 8. Ishimaru, nt. Esashi-gun, Hamatonbetsu-ché, Beniya-Genseikaen, 2 3,1 9. 8juv., 14-15-vm-1990, yn, S. Ueno, Teshio-gun: Toyotomi-ché, Wakasakanai, on coastal sand dune: 1 juy. (1 juv.), 9-viii-1985, nt; 1 do, 1 9, 1-tx- 1988, nt, T. Tanabe. Toyotomi-ché, Toyotomi Spa, 2d, 43 &, 1 juv., 12-13-vim-1990, yn, Monbetsu-gun, Engaru-cho, Engaru JR Station. 2 juv., 30-v- 1985. nr. Kamikawa-gun, Téma-cho, Téma Cave, outside cave, 4 2, 29-30-vi-1985, N. Yoshida, Sunagawa, On a bank of R. Penke- Utashinai, 1 ¢ (1 4), 8-x-1986; 2 ¢ (2 &),. 15-x-1986, nr, Sapporo: campus of Hokkaido Univ,, | &. 1 2, 18-1x-1981, nt: Botanical Garden of Hokkaido Univ.: 9 ¢,9 9 (5 d.1 2), 5-x-1982, nr; 13 6, 16 9, 5-1%-1984; 7 juv. (7 juv.), 8-vm-1986; 3 ¢d (3 3), 9-1x-1986, nv. Sapporo, Maruyama, 23 6.19 2 (20 5,3 &), 5-ix-1986, n7?, Tomakomai, Tomakomai Experiment Forest of Hokkaido Uniy., 1 d, 3 2, 19-1x-1980_ wr. YAMAGATA PREF,; Obanazawa-shi, Obanazawa, | d, 1 9, 4 juv., 29-vm-1983, A, Otaka; 6 d, | 2, 4-x-1984, A. Otaka; Obanazawa-shi, along Route 347, 2 °, 9-x-1988, T. Tanabe. CatBA PREF: Awa-gun, Amatsu-Kominato-ch6, Awa-Amatsu, Saneiri coast: J 3,1 2,2 juv., 21-v-1983; 1 do, 18-1x-1983, K. Ishii; 2 d, 1] 2, 18-x1-1983, K. Ishi. Awa-Amatsu, Saneiri, Matsugabana, under growth of maritime fern, Cyrtomium falcatum, 1-2m,23 d,21 2 (16 3), 27-vii-1984, nT. TOKYO PREF.: I, Hachijo, Mine, 2 ¢, 2 &, 17-18-x1-1983, H. Okada, TOYAMA PREF: Toyama-shi: Yokogoshi, | 2, 20-x-1978; I juv., 18-v-1990, N. Nunomura; Hamakurosaki, Pinus thunbergi forest, | juv., 2-v-1979; 3d, 1 2, 6-viti-1980, N. Nunomura. WAKAYAMA PREF ; Nishimuro-gun, Shirahama-ché, Shirahama, Seto Marine Biological Lab., | d,3 2, 10-vu-1983, 8. Otsuka; 29d, 41 2,43 juv. (160,19, 9 juv.), 29-vn-1983, nt-ToTTORIPRER.: lwami-gun, Iwami-ché, Uradome coast, Kamogaiso, 4d, 39, 7-1x-1988, nr, R. G. Holmberg; Ketaka-gun, Ketaka-ch6, Yatsukami, Anedomari coast, 1d, 39, 5-1x-1987, NT. OKAYAMA PREF: Oku-gun, Ushimado-ché, Ushimado Marine Biological Station of Okayama Univ., Benten-iwa, 1d ,4 2, 10-vm-1983, T- Sato. HIROSHIMA PREF.: I. NOmi-jima, Irukanohana: 12 juv., 13-vi-1976; 1d, 4-v-1977, nv. EHIME PREF:: Onsen-gun, Nakajima-ché, I. Nakajima, Okushi: 3 2, 6-7-vil-1971: 1 2, 13-vi-1974, nr, Okushi, Seno-hana, 51 3,69 2 (30 d, 6 2), 26-vm-1986, nr. I. Nakajima: Himegahama, | 2, 13-vi-1974, nt; I. Takashima off Himegahama, 3 ¢,3 @, 6-vin-1971, Nr. Matsuyama, Mt. Fukumi, Fukumiji, 860m, 2 juv., 6-1x-1970, Nr. NAGASAKI PREF: Iki-gun, Ishida-ch6, Kukishoku, 4 d,5 @ , 2 juv., 20-v1-1990. M. Yamashita. KUMAMOTO PREF: Ushibuka-shi, 1. Tojima, 2 juv. M. Yoshikura; Amakusa-gun, Itsuwa-ch6, Oniike, 3 d,1 2 , 2 juv., 8-vi-1958, M. Yoshikura; Matsushima-cho, Aitsu,4 ¢ ,1 9, 10-vm-1957 M. Yoshikura; Matsushima-ché, I. Maejima, 2 d , 4 2, 20-vu-1963, M. Yoshikura. KAGOSHIMA PREF.: J. Yakushima, Shiratani-Unsui-kyé to Mt. Miyanoura-dake, | 2, 2-5-vi-1983, H. Okada. 1. Tanegashima: Hamada, ljuv., 11-vil-1983, Sk. Yamane; Makigawa, 3 juv., 3-5-v-1984, Sk. Yamane. Kumage-gun. Kamiyaku-ché, 1. Kuchinocrabu-jima, 1 3, 27-1v- 1984, Collector unknown. MATING BEHAVIOUR AND FEMALE SPERM STORAGE [MN PHOLCUS PHALANGIOIDES (FUESSLIN) (ARANEAE) G. UHL Uhl, G. 1993 11 11: Mating behaviour and female sperm storage in Phaleus phalangioides (Fuesslin) (Araneae). Memoirs of the Queensland Museum 33(2): 667-674. Brisbane. [SSN 0079-8835. Females of Pholcus phalangioides do noi possess treceptacula semints but store transferred spermatozoa in their genital cavity. The spermatozoa are embedded in glandular secretion that is discharged from two accessory glands situated in the posterior wall of the genital cavity. The gland cells belong toacomplex type of class 3 cells according to the classification of Noirot and Quennedy (1974, 1991). Withthe sperm mass ofa single copulation the females are able to fertilize several batches of eggs, although the sperm might be easily washed out with the passage of the first batch of eggs (Forster, 1980), Nevertheless, females allow repeated copulations. The first copulation usvally took over an hour but subsequent copula- tions lasted only a few minutes, no matter whether the female mated with the same or with a different male. Copulations after egg-laying tended to be long. Male spiders might achieve reproductive advantage in copulating with any female they meet and females might have an intereslin filling up their storage capacities. Pholcus phalangioides Weibchen besitzen keine Receptacula seminis im iiblichen Sinne, sondern speichern die wihrend einer Kopulation iibertragenen Spermien im Hohlraum des Uterus externus. Die Spermien werden dort in cin Sekrei cingelagert, welches von zwei akzessorischen Driisen produziert wird. Diese Driisen befinden sich in der posterioren Wand des Uterns externus. Die Driisenzellen sind nach einem Klassifikationssystem, das fiir epidermale Driisenzellen von Insekten erstellt wurde (Noirot and Quennedy, 1974, 1991), einem komplizierten Typ der Klasse 3 zuzuordnen. Mit den Spermien, dic wiihrend einer einzigen Kopulation iibertragen wurden, kénnen die Weibehen mehrere Eigelege befruchten (UHL, in press a), entgegen der Annahme, die Spermien kinnten wabrend der ersten Eiablage leicht ausgewaschen werden (Forster, 1980). Dic Weibchen lassen dennoch mehrcre Kopulationen zu, wobei die erste Kopulation gewohnlich tiber cine Stunde davert, jede weitere Kopulation schon nach wenigen Minuten abgebrochen wird, unabhiingig davon ob ¢s sich um das selbe oder um ein neves Mannchen handelt, Nach einer Eiablage lassen die. Weibchen wieder lange Kopulationen zu, Fur die Mannchen mag és von Vorteil sein sich mit jedem Weibchen zu paaren dem sie begegen, und Weibchen kénnten ein [nteresse daran haben thre Speicherkapazitét voll auszuschopfen. (Araneae, Pholcidae, Pholcus phalan- inarceye ‘perm storage, glands, secretion, ultrastructure, repeated matings, copulation uration, Gabriele Uhl, Institut fiir Biologie I (Zoologie), Universitit Freiburg i,Br., Albertstrage 2/.a, 7800 Freibury i.Br., Germany; 28 October, 1992, Most female spiders store sperm within storage Structures that are spatially separated from the genital cavity, Some “primitive” spider families such as Diguetidae, Liphistiidae, Archaeidae and Pholcidae retain the sperm mass within the geni- tal cavity itself (Forster, 1980). Forster assumed that the bursal storage mode has little survival value as the sperm mass gets flushed out with the passage of the eggs and therefore, storing the spermatozoa in spatially separated storage struc- tures would eliminate the need for repeated in- semination. Despite the bursal storage mode, female Pholcus pkalangioides (Puesslin) are able to fertizile numerous batches of eggs with the sperm of a single insemination (Uhl, in press a). However, the females probably do not rely on the amount and fertility of the spermatozoa trans- ferred during a single copulation. This would be risky as the spermatozoa might be defective or insufficient. Lexpect the females to fill up their storage capacity by means of repeated matings at least after egp-laving when few clumps of sper- matozoa remain in the genital cavity after oviposition. However, if the female does not have the opportunity to copulate repeatedly. the stored spermatozoa can be sufficient for fertilizing fol- lowing egg batches successfully_ This study wall also give a brief morphological account on the bursal storage mode in P. phalangioides and will present histological ynd ultrastructural findings on the glandular tissue that exudes its prodwet into 668 MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 1. Dorsal wall of genital cavity of P. phalangioides. A, Pore plates viewed from genital cavity; B, Pores that exude secretion, C, One pore plate from its dorsal side, glandular tissue removed; D, cuticular ductules of accessory glands. the genital cavity for sperm storage. For more behaviour the spiders were kept in couples in detailed information see Uhl (in press b, c). plastic boxes (16.5x9x6.5cm) and their behaviour was recorded day and night on video tape. MATERIAL AND METHODS Five different experimental set-ups were used in order to answer the indicated questions: Juvenile Pholcus phalangioides were reared 1. Duration of copulation: Virgin females were individually in the lab, To investigate mating offered unexperienced males. BEHAVIOUR AND SPERM STORAGE IN PHOLCUS 2. Copulation duration with sperm-depleted males; Virgin females were offered recently ex- perienced males (1/2 hour after termination of copulation). 3. Repeated matings with same partner: Pre- viously virgin females were kept with previously unexperienced males for up to 20 days. 4. Repeated matings with changing partner: 1/2 hour after their first copulation females were of- fered unexperienced males. In order to check the influence of box-size on mating behaviour 4 experiments were carried out using 2.5 times bigger boxes (18x12x11-5cem). §. Duration of copulation after egg-laying: Post-oviposition females that had mated once were allowed to copulate again with unex- perienced males. For SEM studies adult females were anaes- thetized, dissected and fixed in 70% ethanol or Bouin. In order to investigate the sclerotized parts of the female genital tract, the female genitalia were put in 5% NaOH solution until the soft parts were dissolved. Some genitalia were opened or cut with a sharp razorblade to Jocate the sperm mass in the genital cavity. They were dehydrated in ethanol, CP-dried, sputter coated with gold and examined in a Zeiss Semco Nanolab 7. For light- and electron microscropy the spiders were anaesthetized and dissected in glutaral- dehyde, After fixation in 2% osmium tetroxide/- glutaraldehyde, they were post-fixed in osmic acid (modified after Franke et al., 1969), dehydrated in graded series of alcohol followed by propylene oxide and embedded in Epon. The semithin sections (0.7-] 2m) were cut With glass knives on a Reichert OmU3 and stained with toluidin. Ultrathin sections were cut with glass knives and diamond knife, They were stained with urany! acetate, counterstained with lead citrate and examined in a Zeiss EM9 electron microscope. RESULTS Mating BevAviour 1. Virgin females copulated with unex- perienced males over an hour (x=64.5 minutes; sd= 26,6; shortest duration: 16 min, longest dura- tion: 122 min; n=42). This supports findings of Reagan and Reagan (1989) who investigated 104 pairs (mean copulation duration: 72.3 min; sd=43.3; shortest: 10 min, longest: 304 min). 2, Five males that had mated with virgin females (long copulation 1) were brought half an hour after copulation to another virgin female. All G49 FIG. 2. A, Genital plate flipped back, dorsal wall of genital cavity revealed. Two pore plates, one con- cealed by secretory ‘plug’; B, secretory ‘plug’ in genital cavity cul sagittally; C, Sperm mass in female secretion in female genital tract. copulations were long (X: 56.8 minutes). The males probably refill their copulatory organs prior to the second copulation. The filling was observed in only one case by chance and was not detectable on the video recording. 3, Unexperienced males and females were kept in pairs up toa 20 days. Six fernales out of 12 allowed copulation from time to time: one female copulated twice, four females copulated 3 times, one female copulated five times. The second and the following copulations were always very short, they took only 2 to 5 minutes. Copulation dura- tion tended to decrease in successive matings. 4. Unexperienced males were brought to females that had already mated once (Jong copulation 1), In 9 of 14.cases the females allowed 670 4 Copulation duration im 1. Virvin 9 with unexperienced 3 64,5 (16-12 2. Virgin 2 wath recently 5 2; 26.6) cieieadé 56:8 (37-75; 13.9) 3. Second copulation with same d —[6* 13.6 (2-5; 1,02) 4, Second coptilation with , unexpeni 4 ¢ 2,6 (1,5-5; 1,0) 5. Post-oviposition 2 with onexpenenced & 59.6 (21-103; 314) TABLE |. Mating behaviour in P. phalangioides as 4 function of female reproductive history. Only cases of copulation given. Range and standard deviation in parentheses, further copulation. Again, second copulations lasted only a few minutes (1.5-5 min). Control experiments using bigger boxes showed that 3 females out of 4 allowed repeated matings (4.5; 2: 141 min), 5. Seven females that had mated once (long copulation 1) and were kept separately after- wards, had access to males after oviposition. Copulation duration was long. Copulation duration seems to depend on the reproductive history of the females (Table 1), Tre Genirat Cayrry The dorsal (posterior) wall of the genital cavity is characterized by two oval pore plates (Fig. 1A). The pore plates converge in direction of the ridges and grooves that make up the heavily sclerotized valve which separates the genital cavity from the oviduects. Both plates are perforated by pores of 3-5yum in diameier (Fig, 18), The pores are in contact with gland cells that exhude their glan- dular secretions into the cavity (Fig. 1B). The tissue-free pore plates reveal the canal zones of the glandular tissue when looked at from their dorsal side (Fig. 1C). Situated in cavities. cone-shaped hollow structures are apparent (Fig. 1D). These are the distal regions of the canals that Open into the uterus externus as the pores of the pore plate. Proximally the canals change into thin ductules. that exhibit a rough surface after 6- 10j.m (Fig. 1D). SPERM STORAGE The accessory giands discharge their products through the pores of the pore plates into the genital cavity and form two portions of secretory ‘plugs’. (Fig. 2A). Durning copulation, the male transfers sperm mass into the female secretion (Fig. 25). The spermatozoa are surrounded by individual secretory envelopes, they are coiled and inactive (Fig, 2c). MEMOIRS OF THE QUEENSLAND MUSEUM FIG, 3, Semithin section of accessory glands, A, Lon- gitudinal section. Arrows mark nuclei of differentcell types, Ba: basal lamina, E2: outer envelope cell, G: gland cell, m: microvilli, P: pore plate, s: secretion of the gland cells, S: secretion in genital cavity: B, Transverse section. Arrows and stars mark nuclei of different cell types. Scale lines: 20pm. THe Accessory GLANDS The glandular tissue is composed of highly elongated cells (Fig. 3). Different cell types form the gland with various nuclei at different levels (Fig. 3A). The gland consists of lightly stained cells whose nuclei lie close to the basal lamina, and densely stained cells with more distal nuclei. Nuclei of other cell types lie mainly in the centre, Secretory vesicles are apparent in the densely stained cells (the gland cells G). Accumulations of such vesicles are found in the apical second third of the glandular tissue. Each accumulation forms two portions of tightly packed secretory globules that discharge their contents into a com- mon reservoir which 1s homogeneously coloured (Fig. 3A, B). Bordering on the gland’s orifices is a zone of BEHAVIOUR AND SPERM STORAGE IN PHOLCUS greyish coloration that is formed by the light coloured cells (outer envelope cells E2). Histology and ultrastructure show that the glan- dular tissue includes many similar units, each provided with a cuticular ductule that leads to the pore plate (Fig. 3A). Each unit comprises two gland cells and two envelope cells. The two gland cells (G1, 2) join each other to form a common reservoir (Fig. 4, 58). They are rich in granular endoplasmic retuculum (Fig. 5A), mitochondria and dense secretory vesicles and exhibit humerous golgi complexes in the supranuclear region. The vesicles vary in size (up to 1.5m in diameter) and get more numerous in the distal cell region, They are enclosed in a close-fitting membrane which is obscured by the matching density of the mature granula. The inner envelope cell(E1) surrounds and partially separates the two gland cells (Fig. 5B, C, D) and forms the proximal part of the ductule (Fig. 4c). The outer envelope cell (E2) surrounds all of the previously men- tioned cells. Its cytoplasm is poor in organclles (Fig. 5A, B, D). It produces the distal part of the ductule and forms numerous microvilli that gather round the ductule and the orifice (Fig.58) and represent the greyish zone visible in the semi- thin section of Fig. 3A. The gland cells and the outer enyelope cell form a so-called basal labyrinth adjacent to the basal lamina (Figs 4, 5A). The glandular units are separated from each other by elongated epithelial cells. DISCUSSION The glandular units of the accessory glands in P. phalangioides belong to class 3 cells (Noirot and Quennedy, 1974, 1991). According to that classification, a gland cell is associated with a cuticular ductule that has been secreted by a ‘canal’ cell. In P. phalangioides however, there are two gland cells that are always connected by a common microvilli region, one inner and one outer envelope cell that form a double ensheath- ing of the gland cells. Moreover, both envelope cells take part in producing the canal that leads to the pore plate. Therefore, the glands studied here belong to a complicated type of class 3 cells. There is Some information on gland structures in female spider genitalia, The glands of the re- ceptaculum seminis of Telemidae belong to class 1 type of gland cells (Lopez and Juberthie-Jup- eau, 1983), and in some Theraphosidae De Carlo (1973) stated aclass ] composition. However, the light microscope study of Kovoor (1981) indi- all FIG. 4. Schematic reconstruction of one glandular unit of accessory glands, Ba: basal lamina, BL: basal labyrinth, D: ductule, El: inner envelope cell, B2: oulerenvelope cell, G1, 2; gland cells, N; nucleus, P; pore plate, 672 MEMOIRS OF THE QUEENSLAND MUSEUM BEHAVIOUR AND SPERM STORAGE IN PHOLCUS 6 cates that a more complex gland composition as in P. phalangioides might not be exceptional. The glandular units of P. phialarigioides could function as a two-component-system, as the outer envelope cell shows conspicuous microvilli that surround the orifices of the ductules. This indi- ciles secretory activity although the outer en- velope cell contains no stainable secretory droplets or granules, Their product could have got lost dunng fixation or. the cells produce and release their product only on demand. Not all the secretory activities of cells are accompanied by Microscopically detectable accumulation of the product in the cytoplasm. Apart from that, the outer envelope cell exhibits a basal Jabyninth- It contributes to enhance the exchange of molecules between the haemolymph and the cells (Berridge and Oschmann, 1972) and characterizes active cells that take up or transfer material from or to the haemolymph. The glandular secretions might setve various functions such as nutrition of the sperm (Coyle e al,, 1983, De Carlo, 1973, Engelhardt, 1910; Forster, 1980), pheromone production (Kovoor, 1981) or sperm displacement from the sper- mathecue into the genital cavity during oviposi- lion (Forster e7 al., 1987; Lopez, 1987; Lopez and Juberthie-Jupeau, 1983), Brignoli (1976) and Lopez and Juberthie-Jupeau (1983) considered activation of sperm prior to fertilization, The glandular tissue might be responsible for trigger- ing activation Via a secretary product that gets released exclusively before oviposition. Further, the females might achieve advantages from resorbing the sperm mass ont of the genital cavity. 1 consider the secretion in the female genital tract of P. phalangioides serves primarily as a depot for the sperm that guarantees successful storage as the onset of the female receptivity corresponds with the time needed to fill the geni- tal cavity with glandular secretion (Uhl, in press a}. Concerning any other possible functions, specific investigations are still lacking. The bursal storage mode 1s considered a ‘prim- ive’ mode with little survival value as the sper- Le) matozoa are liable to be washed out during oviposition (Forster, 1980). Nevertheless, fe- males of P. phalangioides succeed in producing several fertile batches of eggs after a single mating (Uhl, in press a). Although females de not depend on repeated insemination, they allow further copulations. These always last only a few minutes in constrast lo the first copulation that lasts over an hour and there ts wo apparent difference in copulation dura- tion between second copulations with the same or with a different male. If new males are able to replace sperm of a previous male, longer copula- tions would be expected. Sach short copulations may suggest that males are able to assess female virginity or reproductive history during insertion of their palpal structures and then decide on fur- ther investment of time and energy. It has yet to be investigated whether successive copulations result in a transfer of spermatozoa at all, which will also give information on sperm precedence, Provided they transfer sperm and fertilise at least some eggs, tt would be advant- ageous for males to mate with any female they meet. The females, on the other hand, can be expected to fill their storage structure with as many spermatozoa as possible to achieve the highest possible reproductive success. Depend- ing on the amount of sperm already accumulated in the genital cavity females might allow further copulations and hence, decide on copulation dur- ation, Indeed, there is some evidence thal the female terminates copulation, ACKNOWLEDGEMENTS I wish to thank my supervisor Prof. Dr. P. Weygoldt (Freiburg) for making this work pus- sible. Dr. M. Schmitt (Bonn) and two anonymous teferees gave helpful comments on the manu- script. Without a grant from the Studienstiftuag des Deutschen Volkes and additional support from the Organizing Committee participation al the Xllth Congress of Arachnology, Bosbane would have been impossible. FIG, 5. Ultrathin sections of accessory glands. A) Longitudinal section. Nuclear region of gland cells. 4, Longitudinal section. Two gland cells join to form common microvilli region, surrounded by two envelope cells forming first part of canal (arrow). C) Longitudinal section, Microvilli region. Arrow shows cleaving bacterium. D) Transversal section. Beginning of ductule. Gland cells joined, enveloped twice. E) Microyilli region of outer envelope cell close to pore plate. Small ductule (arrow); BL: basal labyrinth, 1: Inner envelope cell, E2; outer envelope cell, cr: endoplasmatic reticulum, G1: gland cell 1, G2: gland cell 2, n: nucleus, m: microvilli, s: secretory droplets, All scale lines, 2m. 674 LITERATURE CITED BERRIDGE, M.J, & OSCHMAN, J.L. 1972. ‘Transporting epithélia’. (Academic Press, New York, London). BRIGNOLI, P.M. 1976. Ragni d'Italia XXIV. Note sulla morfologia dei genitali interni dei Segestriidae e cenni sulle specie italiane (Araneae). Fragmenta Entomologica 12: 19-62. COYLE, F.A., HARRISON, F,W., MCGIMSEY, W.C. & PALMER, J,M. 1983, Observation on the struc- ture and function of spermathecae in haplogyne spiders. Transactions of the American Micros- copical Society 102: 272-280. DE CARLO, J.M. 1973. Anatomia microscopica de las espermatecas de los generos Grammostola y Acanthoscurria. Physis Seccion C, Buenos Aires 32(85); 329-342, ENGELHARDT, V. 1910. Beitrige zur Kenntnis der weiblichen Copulationsorgane ciniger Spinnen. Zeitschnifi fiir wissenschaftliche Zoologie 96: 32- 117. FORSTER, R.R. 1980. Evolution of the tarsal organ, the respiratory system and the female genitalia in spiders. Verhandlungen des 8.Internationalen Arachnologen KongreB, Wien 1980: 269-283. FORSTER, R.R., PLATNICK, N.I. & GRAY, M.R, 1987, A review of the spider superfamilies Hypochilidae and Austrochilidae (Araneae, Araneomorphae), Bulletin of the American Museum of Natural History 185: 1-1] 16. FRANKE, W.W., KRIEN, 8. & BROWN, R.M. 1969. Simultaneous glutaraldehyde-osmium tetroxide fixation with postosmication, an improved fixa- tion procedure for electron micoscropy of plant and animal cells. Histochemistry 19: 162-164. MEMOIRS OF THE QUEENSLAND MUSEUM KOVOOR, J. 1981. Une source probable de pheromone sexuelles: les glandes tégumentaires de la région génitale des femelles d’araignées. Atti della Societé Toscana di Scienze Naturali, Memoire Serie B, Supplemento 88: 1-15. LOPEZ, A. 1987. Glandular aspects of sexual biology. Pp. 121-131. In Nentwig, W. (ed.). ‘Ecophysiol- ogy of spiders’, (Springer: Berlin, Heidelberg, New York), LOPEZ, A. & JUBERTHIE-JUPEAU, L. 1983. Struc- ture et ultrastructure de la spermathéque chez Telema tenella Simon (Araneae, Telemidae). Mémoires Biospéologiques 10; 413-419. NOIROT, C. & QUENNEDY, A, 1974. Fine structure of insect epidermal glands. Annual Review of Entomology 19: 61-80. 199]. Glands, gland cells, glandular units: some comments on terminology and classification. An- nales de la Societé Entomologique de France (N.S.) 27: 123-128. REAGAN, N.L. & REAGAN, A.P. 1989. Mating and egg production in Pholcus phalangioides. American Arachnological Society, Newsletter 40. UHL, G. (in press a). Sperm storage and repeated egg production in female Pholcus phalangioides (Fuesslin) (Araneae), Bulletin de la Societé Neuchateloise des Sciences Naturelles, Actes de la XIfléme Colloque Européen d’ Arachnologie, Neuchitel 2.-6, Sept. 1991. (in press b). Genital morphology and sperm storage in Pholcus phalangioides (Fuesslin) (Araneae). Acta Zoologica, Stockholm 74. (in press c). Ultrastructure of the accessory glands in female genitalia of Pholcus phalangioides (Fuesslin) (Araneae Arachnida). Acta Zoologica, Stockholm 74. THE BIOLOGY OF SPIDERS AND PHENOLOGY OF WANDERING MALES IN A FOREST REMNANT (ARANEAE: MYGALOMORPHAE) GRAHAM F.C. WISHART Wishart, G.F.C. 1993 11 11: The biology of spiders and phenology of wandering males in a forest remnant (Araneae: Mygalomorphae). Memoirs of the Queensland Museum 33(2): 675-680. Brisbane. ISSN 0079-8835. Eight syntopic mygalomorph species, four of one genus, are recognised as inhabitants of a small remnant forest. Over six years 1,207 mature males were trapped and collected from a nearby home swimming pool and the wandering times of mature males of the species are compared, The population density within the forest is estimated. It is suggested the high number is because of an ‘edge effect’ supported by a reduction in predator numbers, an ‘island effect’ and that mygalomorphs have low dispersion powers, long life cycle and sedentary life style. )Mygalomorphae, Hadronyche, Misgolas, Stanwellia, community, forest, rem- nant, phenology, population, syntopic, wandering. Graham F.C. Wishart, ‘Scalloway’, Willowvale, Gerringong, New South Wales 2534, Australia; 23 November, 1992, Phenological studies of spiders commonly con- sider the distribution and abundance of species in relation to habitat variation or disturbance (Peck and Whitcomb, 1978; Koch and Majer, 1980). Studies of male spider wandering patterns are less common and are usually associated with taxonomic revisions of particular groups (Coyle, 1971; Raven, 1984). Main (1982) synthesised male wandering data for her studies of arid zone spiders. This paper presents male wandering patterns over a six year period for six species of syntopic FIG. 1. Aerial view, easterly aspect, from study site towards Gerringong township. 676 MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 2. Aerial view, south-westerly aspect, of study site. Pool length is 10m. forest mygalomorphs and also discusses possible ecological effects which could account for the viability of the spider population. The long term data gathering was enabled by the serendipitous location of an in-ground swimming pool acting as a large pit-fall trap close to remnant forest. STUDY AREA The study site is on the property ‘Scalloway’ (34°44" 11"S, 150°47°23"E) (Figs. 1, 2), near Ger- ringong, N.S.W., and is a remnant piece of mar- ginal Complex Notophyll Vine Forest (Bywater, 1978) at an altitude of 110m. It is a fragment (ca 95m x 55m) of the original ‘Illawarra Scrub’, varying forest types which occupied much of the coastal strip east of the escarpment in South East- ern Australia between the towns of Stanwell Park in the North and Bomaderry on the Shoalhaven River in the south, a distance of 75km. Land clearing removed over 80% of this original vegetation (Fuller and Mills, 1985) and took place mainly between 1850 and 1910, the rem- nants being restricted to land unsuitable for graz- ing because of steep gradients and rock outcrops. The forest overstory includes the trees Syncar- pia glomulifera and Alphitonia excelsa and several vine species forming a discontinuous canopy at a height of about 12m. The understory consists mainly of the small tree Commersonia fraseri and the exotic woody scrambling shrub Lantana camara. L. camara intrudes within the forest but is dense and extensive around the forest edge (not allowed for in the forest dimensions) preventing the entry of cattle. The site is on the edge of a ridge and slopes rapidly downwards to the north east. The soil is of volcanic origin. The surface soil is thin and spread over a basalt bedrock. Large but moveable rocks are prolific. Leaf litter is ca Sem deep. METHODS Wandering mygalomorph spiders trapped in a 10m long swimming pool 15m from the forest edge were collected daily from 1 July 1985 to 30 June 1991. Variables possibly affecting the num- bers of spiders trapped, such as domestic lighting, maintenance of grounds and ability of different species to wander further or more quickly than others, were not taken into account. For three years from 28 August 1986 to 25 October 1989 the burrows within a plot 1.5m? were examined weekly, RESULTS ComMuniry COMPOSITION Mature males of eight species of mygalomorph spiders were collected from the pool, viz.: Mis- golas hubbardi Wishart, 1992 (Idiopidae), M. dereki Wishart, 1992, M. kirstiae Wishart, 1992, M. robertsi (Main and Mascord, 1974), Hadronyche sp. (Mlawarra group) and Afrax sp. SPIDER BIOLOGY IN A FOREST REMNANT TOTAL NUMBER OF SPIDERS FOR 6 YEARS nN as by a a © ae Ww a r N 12-8 26-8 9-9 23-9 7-10 21-10 4a 18-11 677 16-6 30-6 19-5 + i) DAYS OF THE YEARS FIG. 3. Total number of Misgolas hubbardi captured on same days of years for six years from 1.7.85 to 30.6.91. (Hexathelidae), Stanwellia hoggi (Rainbow, 1914) (Nemesiidae), and Kiama lachrymoides Main and Mascord, 1971 (Cyrtauchentidae), The Hadronyche sp. is that referred to as Hadronyche sp. 20 by Gray (1987). The Atrax sp. is smaller but similar morphologically to A. robustus Cambridge, 1877. It differs also in that males wander from October to December whilst those of A. robustus wander mainly in January (Gray, 1986). They are considered here to be different species. PoruLATION DENSITY Because much of the surface area of the forest floor is covered by large rocks and occupied by trees the 1.5 m* plot cannot be representative of the whole forest area. However, an extrapolation 10 9 TOTAL NUMBER OF SPIDERS FOR 6 YEARS a fy te ee OD Oe ) - i] oo UF r &§ - & = Nw ~ mw o 21-10 411 18-11 (based on the assumption that the ratio of the number of burrows occupied by all mature female spider species to the number of burrows occupied by M. hubbardi is equivalent to the ratio of the number of captured mature male spiders of all species to the number of captured mature male spiders of M. hubbardi) indicates there should be 41 mature female mygalomorphs per m” in the 1.5m* plot. In the 1.5m? plot the maximum number of burrows counted at one time was 55. These in- cluded open burrows, those known to exist but temporarily sealed and very small open burrows of which most failed to persist. There were 27 burrows larger than 8 mm in diameter of which 10 were each occupied by a mature female M. hubbardi. Due to physical limitations in accurate- 19-5 2-6 30-6 ay gy 3 9 7, oe & Oo FS O&O 3 - wo = Ow DAYS OF THE YEARS FIG. 4. Total number of Misgolas dereki captured on same days of years for six years from 1.7.85 to 30.6.91. 678 TOTAL NUMBER OF SPIGERS FOR & YEARS -~ nN oy 1 15-7 27 12-6 26. arr 234 7-10 41) 18-11 21-10 16-12 MEMOIRS OF THE QUEENSLAND MUSEUM eS toy hy Bo yy 1 > * fF So - P BR 2eese tate DAYS OF THE YEARS FIG. 5, Total number of Misgolas kirstiae captured on same days of years for six years from 1.7.85 to 30.6,91. ly counting small burrows and recognizing the presence of the burrows of M. kirstiae and Hadronyche sp. the total count must fall short of the actual mygalomorph population. PHENOLOGY OF WANDERING Ma.gs (Table 1) Wandering mature males of M. hubbardi were found almost throughout each year (Fig. 3). The extensive wandering period of M. robertsi is in- terrupted during January and February when the frequency of capture is reduced (Fig. 6). The wandering period for §. hoggi is also long, ex- tending over six months (Fig. 8). As is customary to expect of male mygalomorphs, the wanderings of M. dereki (Fig. 4), M. kirstiae (Fig. 5) and H. sp. (Fig. 7) are restricted to shortand more precise annual periods. The collections of Arrax sp. and - % in No. ‘ Total Peak active Species i E Peal trapped p= _il™ ee tevieniiet fon the [Nov-Jan. | -Jan. atoll olas dereki gsm —lor Misg [Misgolaskirstiae | kirstiae bs pl. ISept-Nov. lox | 158 ee fete March-May | 86 b- lo.29 | Stanw fete hoget ee Atrax sp oo 2 Kiama lachrymoides INov | Total 1207 a TABLE 1. Summary of numbers and timing of male spiders trapped in pool from 1 July 1985 to 30 June 199]. K. lachrymoides were too small for deductions to be conclusive. During the six year period, 11 female S. hoggi were also trapped in the pool during the months from March to October. DISCUSSION No previous reports have been found of either eight species of mygalomorph spiders or four species of one genus (Misgolas) of spiders exist- ing elsewhere syntopically or sympatrically. The high proportion of mature female S. hoggi collected is surprising, 11 females to 26 males, and 10 of the 11 were taken at times coincidental with the male wandering period. The number reflects the Jong-legged, male-like morphology of the female adapting it to roam. Further, that only one male K. lachrymoides was collected may indicate the inability of the male of this species to wander a long distance a reflection in this case of the male’s short-legged female-like morphology. The usual sexual dimorphism of mature burrowing mygalomorph spiders (female bulky, stout legged; male less bulky, long legged) is contradicted in these two species. Some possible reasons for the dense mygalomorph spider population are offered. First, predators of mygalomorph spiders may have become extinct in the area following human settlement. For example, the bandicoot (Perameles nasuta Geoffroy, 1804), reputed to be a mygalomorph spider predator (Main, 1976; Preston-Mafham, 1984) and once very common in Willowvale, has been rarely seen by the author and not at all for 15 years. Here then, possibly, is SPIDER BIOLOGY IN A FOREST REMNANT 679 6 2 B 5 wo c ir 2 4 a & 3 3 & a 2 2 Z1 =) o To Be ee Ree PEET EPS Sa Re eS sSstTTEs fs eB DAYS OF THE YEARS FIG. 6. Total number of Misgolas robertsi captured on same days of years for six years from 1.7.85 to 30.6,91, a paradox where habitat destruction and the intro- duction of feral animal pests, may increase, not decrease, mygalomorph spider numbers by decreasing spider predators. Second, the concentration may result from an ‘Island Effect’ where it is found that the popula- tion of an individual species can be far greater than expected when the species is insulated within a small ecological system (separate pers. comms, M.Gray and R.Raven). Also Main (1987) proposed that mygalomorphs are admirably fitted to persist in small isolated areas because of their low dispersion powers, long life cycle and seden- tary life style. Finally, in a larger (ca. 300 ha) forest with complete canopy and separated from the TOTAL NUMBER OF SPIDERS FOR 6 YEARS ws S ‘Scalloway’ site by ca. 400m of pasture land there is a paucity of mygalomorph spider burrows and few insects suitable for prey. Burrows are more common near the forest edge, and so too is insect life with grasshoppers, moths and crickets prolific. Because the ‘Scalloway’ forest remnant is small it is in effect a forest edge throughout with an abundance of suitable prey. Laurence (1991) states, ‘In the tropics, forests near edges exhibit striking changes in microclimate, vegeta- tion structure and composition, disturbance regimes, and invasions of species from adjacent habitats. Thus, in fragmented systems, species that tolerate edge conditions are often favoured’. I suggest that this is the explanation for the presence of this dense mygalomorph population. 7 Pe ee ee oer renee pe eo dae ome tt eo YY & ® - © 2a @ oO 8 TT FF BBS o> © © ¥ S = Re +r Hh He NM BD GO - xX = S eg ¢ 8 a b GF HF HF AK a = - & DAYS OF THE YEARS FIG. 7. Total number of Hadrenyche sp. captured on same days of years for six years from 1.7.85 to 30.6.91. 680 Yr TOTAL NUMBER OF SPIDERS FOR 6 YEARS = = ou gag a2 8 oe) ee oS ou ~ 21-10 ya-17 MEMOIRS OF THE QUEENSLAND MUSEUM Noe ps n A 7 BH te me o> & o + © = - ~ r ~ - a) DAYS OF THE YEARS FIG, 8. Total number of Stanwellia hoggi captured on same days of years for six years from 1.7.85 to 30.6.91. ACKNOWLEDGEMENTS My thanks to the Australian Museum and Dr Michael Gray for the provision of facilities and advice; Mr Paul Askew for field assistance; Mr Harry Mitchell for aerial photographs; Mr George Browning for helpful criticism; and Dr Robert Raven of the Queensland Museum for computing suggestions and encouragement. Especially do | thank my neighbour, Dr Peter Linklater, for the execution of statistical work and the preparation of the graphs and Dr Bill Humphreys of the Western Australian Museum for comments on the data and guidance. | am grateful to the CSIRO Science and Industry En- dowment Fund for its support. LITERATURE CITED BYWATER, J. 1978. Distribution und ecology of rain- forest vegetation and fauna in the Mlawarra. (Thesis, University of Wollongong). CAMBRIDGE, O.P.- 1877. On some new genera and species of Araneidea. Annals and Magazine of Natural History (4) 19: 26-39. COYLE, F.A. 1971, Systematics and natural history of the mygalomorph spider genus Antrodiaetis and related genera (Araneae: Antrodiactidae). Bulletin of the Museum of Comparative Zoology 141: 269-402. FULLER, L. & MILLS, K. 1985, Native trees of central Iawarra, (Weston and Co.: Kiama). GRAY, MLR. 1986. A systematic study of the funnel web spiders (Mygalomorphae: Hexathelidue: Atracinae), (Unpublished Ph_D. Thesis, Mac- quarie University). 1987. Distribution of the funnel web spiders. Pp. 312-321. In Covacevich, J., Pearn, J, & Davie, P, (eds). “Toxic plants and animals’. (Queensland Museum: South Brisbane). KOCH, L.E. & MAJER, J.D, 1980. A phenological investigation of various invertebrates in forest and woodland areas in the south-west of Western Australia. Journal of the Royal Society of Western Australia 63: 21-28. LAURENCE, W.F. 1991, Ecological correlates of ex- tinction proneness in Australian tropical rain forest mammals. Conservation Biolagy (5) 1: 79- MAIN, B.Y. 1976. ‘Spiders’. (Collins: Sydney). 1982. Adaptations to arid habitats by mygalomorph spiders. Pp, 273-283. In Barker, W.R. et al. (eds). ‘Evolutions of the flora and fauna of arid Australia’, (Peacock Publications: Frewville), 1987. Persistence of invertebrates in small areas: case studies of Trapdoor spiders in Western Australia. Pp. 29-39. In Saunders, D. ef al. (eds). ‘Nature conservation: the role of remnants of Native vegetation,’ (Surrey Beatty and Sons: Syd- ney). ; MAIN, B.Y. & MASCORD, R.M., 1971, Anew genus ot diplurid spider (Araneae: Mygalomorphae) from New South Wales. Journal of the Australian Entomological Society 6: 24-30. 1974. Description and natural history of a “tube- building” species of Dyarcyops from New South Wales and Queensland (Mygalomorphae: Ctenizidae). Journal of the Australian En- tomological Society 8: 15-21. PECK, W.B.& WHITCOMB, W.H. 1978, The phenol- ogy and populations of ground surface, cursorial spiders in a forest and a pasture in the south central United States. In Merrett, P. (ed.). ‘Arachnology’. Symposia of the Zoological Society of London 42: 131-137, PRESTON-MAFHAM, R. & K. 1984. ‘Spiders of the world.” (Blandford Press: Dorset), RAINBOW, W.J, 1914, Studies in Australian Araneidac. Records of the Australian Museum 10: 187-270. RAVEN, R.J. 1984, A new diplund genus from eastem Australia and a related Aname species (Diplurinae: Dipluridac: Araneac). Australian Journal of Zoology, Supplementary Series 96: 1-51, WISHART, G.F.C. 1992. New species of the trapdoor spider genus Misgolas Karsch (Mygalomorphae: Idiopidae) with a review of the tube-building species. Records of the Australian Museum 44:263-278. THE MACARONESIAN CAVE-DWELLING SPIDER FAUNA (ARACHNIDA: ARANEAB) JORG WUNDERLICH Wunderlich, J. 1993 11 11: The Macaronesian cave-dwelling spider fauna. Memoirs of the Queensland Museum 33(2): 681-686. Brisbane. ISSN (079-8835. The composition of the cave-dwelling spider fauna of the Macaronesian Islands—Madeira, the Azores and the Canary Islands-is compared with the endemic epigean spider fauna of these archipelagos. The grades of adaptations im the cave-dwelling spiders are compiled, and the following questions are discussed; fromm which geographic regions did the stem species come? What can be said about the evolution of the species? How old are the cave-dwelling spider species? Die Fauna der Hohlenspinnen der Makaronesischen Inseln - Madeira, Azoren und Kanari- sche Inseln- wird mit der endemischen epigdischen Fauna dieser Archipele verglichen, Der Grad der Anpassung an das Héhlenleben wird untersucht und verglichen; die folgenden Fragen werden diskutiert: Wo liegt der Ursprung der Stammarten? Was kann tiber die Evolution und das Alter der hihlen-bewohnenden Arten gesagt werden?[jAraneae, troglobites, Canarian and Macaronesian Islands, Island bialogy, biogeography, evolution. Jérg Wunderlich, Hindenburgstr. 94, D-75334 Straubenhardt 3, Germany; 7 December, 1992. Some island groups in the northern Atlantic— the Canary Islands, the Azores, the Archipelago of Madeira, the small [has Selvagens and by most authors (but not by me) the Cape Verde Islands—are called Macaronesian Islands (Fig. 1). The Macaronesian Islands are mainly of yolcanic origin, only the Eastern Islands (Fuerteventura, Lanzarote) are partly of continental origin and have been probably connected with Africa some million years ago. The first troglophilic and troglobitic Macaronesian spiders were described in 1985 from Tenerife. Now cave-dwellers are known from Madeira (1 species), from the Azores (1 species) and from the Canary Islands (at least 17 endemic species, see Wunderlich, 1991), by far most species are known from Tenerife: atleast 11 species = 10% of the endemics (and perhaps there are hundreds of mostly undescribed insect species of different orders). Especially on the Canary Islands there are many caves. The best studied system of caves on Tenerife - cueva del Viento, cueva Reventon - is more than 16km long; the length of all Macaronesian caves ts perhaps more than 100km, and only a few have been examined intensively. MACARONESIAN CAVE-DWELLING SPIDERS Nearly all cave-dwelling spiders are endemics of one island or even only one cave (Table 1): Three species of those listed (Table 1) are not restricted to a single island: 1. Meta bourneti Simon, 1929 (Tetragnathidac) is a west-palearctic species introduced to a cave on Tenenfe (Canary Islands); 2. Agraecina canariensis Wunderlich, 1991 (Liocranidae) is known from caves on Gran Canaria and Tenerife (Canary Islands); 3. Rugathodes pico (Merrett and Ashmole, 1989) (Theridiidae) is known from caves on Pico and Fajal (Azores). Here I deal with five questions: 1. What is the composition of the Macaronesian fauna of troglophilic and troglobitic spiders and what are the differences to the epigean fauna? 2. Which species are extremely well adapted as cave- dwellers? 3. From which geographic regions did the stem species come? 4. What can be said about the evolution of the species? 5. How old are the cave-dwelling spider species? CAVE-DWELLING AND EPIGEAN SPIDERS The most diverse spider families are shown in Figs 2-3. In the Canarian troglophilic and troglobitic cave-dwellers (Fig. 2): Dysderidae (at least 35%), Linyphitdae (25%) and Pholcidae (25%), the sum of these 3 families 1s 85%. (No Oecobiidae). In the cpigean endemic species (Fig. 3) the composition is quite different: Dysderidae 16%, Linyphiidae 15%, Pholcidae 13%, the sum of these 3 farnilies is44%, only half compared with the cave-dwellers. In the families Dysderidac 2S pla yee pieo F- acormennis MEMOIRS OF THE QUEENSLAND MUSEUM EUROPE R- bellicorun ATLANTIC OCEAN ©. Teaaquinty Ro madetrdieln oy MADEIRA ©, stg teanculetus & ~ Serlecatue & palmeroenate q We caverntcols + LA PALMA 9 T+ skomit L. furcabilie 9 CG AL Lineere W. teddwmndin AFRICA 4, Lhertecavaiain — venenter Q FUERTEVENTURA 4 A. canarlennin Ueermopnor ides f~ Cuerleventurennin in. CANARY ISLANDS FIG. 1. The Macaronesian Archipelagos. Some Macaronesian cave-dwelling spiders (underlined) and their European and Macaronesian relatives. (only Dysdera) and Pholcidae (Pholcus and Sper- mophorides) all epigean genera have evolved cave-dwelling species; in the Linyphiidae only members of 5 from 2] genera with endemic species have evolved cave-dwellers (= 25%). Dysdera is the genus richest in species in caves and out of caves on the Canarian and Macaronesian Islands, Oecobiidae probably do not find their prey -ants- in the caves. HIGHLY ADAPTED CAVE-DWELLERS? Different grades of adaptation to cave life in the Macaronesian spiders is evident in three struc- tures (Table 1): the size of the eye lenses, the body pigmentation and length and slendemess of legs. Some true cave spiders of Dysdera have reduced eyes, but neither depigmentation nor long and slender legs. Ido not know the explana- tion. Thus, perhaps the eye reduction is the best indicator regarding the grade of adaptation to cave life in spiders. For discussion below I choose the following five spider species. 1. Meta bourneti (Tetragnathidae, Tenerife) is restricted to deeper parts of caves, but the eyes are not reduced, the body is only slightly depig- mented, and the legs are nearly of normal length. This species has been introduced from Europe or North Africa. 2. Not strongly adapted is Agraecina canarien- sis, but very variable in the depigmentation and in eye reduction (grades 1-3, Figs 4- 5). The variation is intrapopular. This seemingly troglophilic subterranean species is not restricted to caves. 3. In four Canarian species of Spermophorides, the eyes are more or Jess reduced (Figs 8-1 1); the eyes of an epigean Spermophorides sp. from Tenerife are normal (Fig. 12). Cave-dwelling Spermophorides spp. are not strongly related. The known species occur on four different is- lands. So the eye reduction must have been evolved independently four times, 4, Rugathodes pico is restricted to caves. The spiders are strongly depigmented, they have strongly reduced eyes and the legs are long and slender (grades 3-4, Fig. 6a; cf. Fig. 6b the related epigean R. acoreensis). 5. 1n Troglohyphantes oromii (Ribera and Blas- co, 1986) (Linyphiidae, Tenerife), the eyes are tiny or completely absent (Fig. 13), body and legs MACARONESIAN CAVE-DWELLING SPIDERS Liocranidae Nesticidae Linyphiidae 25% Dysderidae 35% Pholcidae 25% FIG. 2. Composition of Canarian families of troglophilic and troglobitic spiders based on 18 species. are completely depigmented, the legs are very long and slender (all grades between 3 and 4). The adaptations in Canarionesticus quadridentatus (Nesticidae, Tenerife) and in ?Metopobactrus cavernicola (Linyphiidae, Tenerife) are similar. These species show the strongest adaptations to cave life. ORIGIN OF THE STEM SPECIES Macaronesian cave-dwelling neoendemic spiders and their European relatives. The hypothetical origin of all species is the West- Mediterranean area, most came from Europe (Fig. 1), e.g. species of Rugathodes to the Azores - Madeira seems to be a ‘stepping stone’, Centromerus to Madeira. Troglohyphantes came perhaps from Spain to Tenerife, but the sister species is unknown. Walckenaeria came from North Africa to Tenerife, Agraecina came from Dysderidae 16% Theridiidae i, 3% . Linyphiidae 15% Pholcidae 13% : i ; it i Lycosidae Salticidae NN . 5% 6% ‘) Dictynidae ‘ ’ 3% Gnaphosidae 5% Oecobiidae —=S\ Others 9% 25% FIG. 3. Composition of Canarian families of epigean spiders based on more than 400 species. 683 z. Meta bourneti Wpal,T Agraecina canariensis CI(GC,T) Dysdera labradaensis Cl(T) D. ratonensis CI(LP) CI(LP) Lepthyphantes palmeroensis D. chioensis D. ambulotenta Pholcus baldiosensis Spermophorides flava S. reventoni D. esquiveli S. fuerteventurensis Walckenaeria cavernicola D. unguimmanis Centromerus sexoculatus Rugathodes pico ?Metopobactrus cavernicola CI (T) CL(T) Troglohyphantes oromii Canarionesticus quadridentatus TABLE 1, The Macaronesian troglophilic (at least the first two and perhaps the first five species) and troglobitic spider species and the grades of their adap- tations from O (normal structures as in epigean taxa) to 4 (=eyeless or almost so/ completely depigmented/ very long legs, the species listed below); AZ = Azores, CI = Canary Islands, EH = El Hierro, F = Fuerteventura, GC = Gran Canaria, LP = La Palma, M = Madeira, T = Tenerife, Wpal = West Palearctic). Di, distribution; R.E., reduced eyes, Dep, depigmen- tation; Leg, long & slender legs; T, Total. Europe or North Africa to Tenerife (and Gran Canaria). The occurrence of cave-dwelling species of the different genera on Tenerife - e.g. Walckenaeria, Troglohyphantes and Agraecina - are remarkable (Fig. 1). The highest Macaronesian mountain, the 3718m high Teide on Tenerife, seems to be a ‘catcher’ of aeronautic (ballooning) spiders which came from the Western Mediterranean area. This finding is supported by the relation- ships of the endemic spider fauna of the Teide and the Cafiadas, an area surrounding this high moun- tain (cf. Wunderlich, 1991: 104-107). EVOLUTION OF MACARONESIAN CAVE-DWELLING SPIDERS In some spiders, e.g. Canarionesticus quad- ridentatus and Troglohyphantes oromii, no re- lated epigean species is known, and almost nothing can be concluded about their evolution. 684 natal FIGS. 4-7. 4-5. Variable eye reduction in subterranean Canarian Agrdecina canariensis Wunderlich, 1991 (Liocranidae). 6,7. Rugathodes. 6 , d body witheyes and right tibia 1 from the Azores: 6a, of the cave- dwelling R. pico; 6b, of the epigean R. acoreensis, 7. Right male pedipalps ventral: 7a, R. bellicosum (Simon, 1873), Europe; 7b, R. madeirensis Wunder- lich, 1987, Madcira; 7c, R. pico (cavernicolous) and R.acoreensis (epigean), Azores. These species show no differences, (E = embolus). (Several species are not well studied, e.g. Dys- dera species, or only one sex is known). In this connection Treglohyphantes oromit is of special interest because nearly all species of this genus are troglophilic or troglobitic cave-dwellers as well as the species from Tenerife. I can imagine that there has never existed an epigean stem species on Tenerife and that the ancestors, per- haps as a cocoon, has been transported by a bat directly from a European cave to a cave on Tenerife. Several species or subspecies of bats fly from Europe via Madeira to the Canary Islands (Dr. Biscoito, Mus. Munic. Funchal, Madeira, pers. comm.). This hypothesis would explain why there is no epigean Troglohyphantes spp. on Tenerife or another Canary or Macaronesian Is- land. Otherwise I do not want to exclude the MEMOIRS OF THE QUEENSLAND MUSEUM weventont [lave fuerrecavensin Tenbensis pubtot oeamij FIGS 8-11. Eye reduction in Canarian cave-dwellers spiders: 8, Spermophorides reventoniWunderlich, 1991; Fig. 9, S. firertecavensis, 10, 8. flava Wunder- lich, 1991; 11, 8. justoi Wunderlich, 1991, 12, Byes of the cpigean §. tenoensis Wunderlich, 1991, Tenerife. 13. Sometimes completely eyeless prosoma of cave-dwelling Troglohyphantes oramii, Tenerife. possibility that this species is a paleoendemic telict (Peck, 1990: 372-373). Based on the very similar genital organ, in Rugathodes pico and acoreensis they are identi- cal, I found some strongly related spider species (Table 3). In the cave-dwelling R. pico (Table 1 and discussed above), the adaptations to cave life and the differences in some non-genital structures compared with epigean species are very distinct: the eye reduction, the depigmentation and the prolongation of the legs, Fig. 6a; compare Fig. 6b of the epigean species, which is also known from the Azores. Otherwise the genital structures in the two Azorean species show no differences in both sexes (Fig. 7c), but there are distinct differences to madeirensis from Madeira (Fig. 7b) and bel- licosum from Europe (Fig. 7a). So | do believe that R. pico and R. acoreensis are true sibling MACARONESIAN CAVE-DWELLING SPIDERS Introduced species Meta bournedi Paleaoendemic species Neoendemics Cunarionesticus quadridentatus (Nesticidae, Tenenfe}, No known telative, 685 The epigean sibling or sister species/stem species is known, usually from same island, To this group belong most Macaronesian. cave spiders, see below (gencsis/eyolution), Dysderidae, Phaicidae, Linyphiidac, Thendiidac and Lincranidae. TABLE 2. Historical groups of Macaronesian cave-dwelling spiders, Position of Traglohyphantes vromii in list is uncertain; it has no known epigean relative. See below; possible transport by a bat. species (or even subspecies?) and that &, acoreensis also is the stem spectes of R. pice. In Spermophorides, differences in genital and non-genital structures are distinct in both sexes, und perhaps they ure nel sister species, The remaining species in this list arc known only from females. Martin etal. (1989) assume thal some Canarian troglobites can be considered as relict species which evolved after changes in the climate ‘since there have been alternating wet and dry periods .. Causing important changes in the fragile insular ecosystem on the surface.’ (See below: Rugathodes). Furthermore the yearly seasonal changes—hot and dry summers, cooler and more humid winters especially on the Eastern Canary Islands—did perhaps initiate vertical movement of some Species into the ground in the summer and also autecological changes for instance in Centromerus fuerteventurensis Wunderlich, 199] (Linyphiidae). In this species, which is not a cave-dweller, the eyes are reduced as well as in species of Scotargus (Linyphiidae) and Altella (Dictynidae) of other Canarian islands (Wunder- lich, 1991). | Borges and Oromi (1991) do prefer the “adap- tive shifting theory” of Howarth (1973), “This theory does not invoke isolation during climatic (or volcanic?) Changes but instead proposes that the partly adapted ancestors shifled into newly developed niches.’ In my opinion this theory can well explain the genesis of some Macaronesian cave-dwelling spider species including the ones listed above (see Peck, 1990; 366-368). Especial- ly there exists large caves and lava tubes on the Canary Islands, and there are many ecological niches. From the Macaronesian Islands and its spiders ) know three kinds of preadaptations which sup- port the ‘adaptive shifting theory’: 1. A lot of Canarian species are known as hypogean spiders and were caught using special traps in the ground in the so-called 'mesocaver- fous shallow stratum’ (Wunderlich, 199}: 11), From this stratum and from accidental captures under stones | know Cananan species of Dysdera, Spermophorides. Lepthyphantes, Walckenaeria, Altelia, Zimirina and others. These spiders haye moderately reduced eyes and are more or less depigmented, they seem to be troglophilous and not matrocavernicolous, butmicrocavernicolous or myrmecophilous. Agraecina canariensis is a species of this stratum but it also penetrates caves. iA closely related species has been newly dis- covered in a Romanian cave). 2. Another preadaptation is offered in the con- ditions in the laurisilva (the relict laurel forest); high humidity and low changes in temperature. For example 1 found the laurisilva species Treglonata madeirensis Wunderlich, 1987 (Anapidae .1.) in the wet and light part near the entrance of a cave on Madeira (Sao Vincente}. | collected 29 of Lepihyphantes mauli Wunder- lich, 1991 (Linyphiidae) in the same part of this cave; this species probably also came fram the wet forest near lhe cave. 3. The third kind of biotopes that lead to troglobilic conditions are under stones and under leaves on trees at places witha high humidity near stretches of water, At such places, under stones as well as under leaves on trees, I found on the Azores R. acoreensis, the epigean sibling/stem species of the cave-dwelling R. pico. Under a stone over flowing water on Tenerife | found partly depigmented spiders of Walckenaeria alba, Act of Macaronesian CaVE-DWELLING SPINER SPECIES The age of the Macaronesian caves remains unknown. The youngest Macaronesian Islands, the Western Azorean and the Western Canarian islands, are only very few (1-27) million years old. Two spider species, Pholeus reguensiz and Walckenaeria cavernicola, are cave-dwellers at the Cafadas on Tenenfe. The greatest age of these species could be the same as the age of this part of Tenerife, at least 200 000 (up to 2 million) Veurs, Rugathades pico is known only from caves of the Azorean islands Pico (a young island) and Fajal. After Ashmole (in litt, 1991) these Azorean 686 Cave-dwelling speci pigean relatives Spermophorides fuertecavensis S. Pfuerteventurensis Centromerus sexoculatus, and sp. noy. | C. variegatus Walckenaeria cavernicola Rugathades pico R.acoreensisi Islands had perhaps a land bridge during the last glaciation. So this species probably evolved from its closely related epigean stem species, near or identical with R. acoreensis, perhaps not later than 10 000 years ago (= 10 000 generations). From genital structures, in both sexes there are no differences, speciation should have happened, geologically, not long ago, that means at the end of the last glaciation. But this idea is very vague; perhaps the speciation happened much Jater, and R. pico was transported by bats from one island to the other only very few thousand years ago (Wunderlich, 1991: 200-201), Wunderlich (1991) gives further details of these cave-dwell- ing spiders and their taxonomy. ACKNOWLEDGEMENTS I like to thank the Deutsche Forschungs- gemeinschaft, Bonn, forthe loan of optical instru- ments, and I also like to thank S.B. Peck, Ottawa, MEMOIRS OF THE QUEENSLAND MUSEUM TABLE 3. Macaronesian cave-dwelling troglo- Fuerteventura (Cana [Madeira | Limyphiidae | La Palma (Canary Is.) Is.) [Pholcidae philic or troglobitic spiders and their nearest epigean relatives, pos- sible stem/ sister/sibling species from same is- land. for his kind comments to the first version of the manuscript. LITERATURE CITED BORGES, P. & OROMI, P. 1991. Cave-dwelling ground beetles of the Azores (Col., Carabidae), Mémoires de Biospéologie 18: 185-191. HOWARTH, F.G. 1973. The cavernicolous fauna of Hawaiian lava tubes. 1. Introduction. Pacific In- sects 15; 139-151. MARTIN, J.L. et ai. 1989. Sur les relations entre le troglobies et les espéces epigées des Iles Canaries. Mémoires de Biospéologie 16: 25-34. PECK, S.B. 1990. Eyeless arthropods of the Galapagos Islands, Ecuador: composition and origin of the cryptozoic fauna of a young, tropical, oceanic archipelago. Biotropica 22: 366-381. WUNDERLICH, J. 1991. Die Spinnen-Fauna der Makaronesischen Inseln. Taxonomie, Okologie, Biogeographie und Evolution. The spider fauna of the Macaronesian Islands. Taxonomy, Ecology, Biogeography and Evolution. Beitraege Araneologie, vol. 1, 619 pp. RELATIONSHIP BETWEEN FOOD INTAKE AND SPIDER SIZE IN TEMPERATE ZONES: EXPERIMENTAL MODEL FOR AN ORB-WEAVING SPIDER FREDERIC YSNEL Ysnel, F, 1993 11 11: Relationship between food intake and spider size-in temperate zones: experimental model for an orb-weaving spider. Memoirs of the Queensland Museum 33(2): 687-692. Brisbane. ISSN 0079-8835. A method is presented that allows calculation of the energy intake by an orb-weaving spider, Lorinioides cornutus (Araneae; Araneidac) under natural conditions throughout the spider's life. A laboratory study provides several relationships between individual energetic con- sumption and size of spiders depending on the thermal conditions of their environment. | observe a preferred temperature (21°C) at which spiders have the biggest consumption. A mode] (pseudo-cubic spline) is constructed for the calculation of energy intake by each juvenile instar, Energy requirements of the adult population are estimated from the repor- duction rate observed in the field. The energy requirements under natural conditions and the total weight of prey consumed by the population in the course of its biological cycle can be inferred. In the mesophilous heathland investigated, the total fresh weight of prey consumed by the population during the life cycle is 18.2 kg.ha™ . Cette étude vise a selier les taux de survie, de croissance et de reproduction d une espéce Orbitéle Lariniaides cornutas (Araneae: Ataneidae), au nombre de proics consommées en miheu naturel au cours du cycle biologique. Cette analyse est déduile d une approche bioénergétique. Au laboratoire. les consommations énergéliques et Ia croissance des araignées sont testées en fonction de | environnement thermique. Ces cxpériences mettent en évidence la présence d un optimum thermique d ingestion qui modifie la croissance et la consommation des individus. Un modéle d ajustement (spline pseudo-cubique) Jiant la lempérature, la taille des araignées et la température ambiante est proposé pour estimer | énergie ingérée en phase juvenile, L énergie ingéréc en phase adulte est estiméc en comparant les parametres taux de reproduction -consommation caloulés en éleyage, au taux de reproduc- lion observes en milieu naturel. Les besoins énergétiques sont ensuite convertis en quantilé de proies capturées, Sur la lande mésophile étudiée, la population capture en poids frais, 18.2 kg de proles par hectare au cours du cycle biologique. OPepulation energetics, Araneae, Araneidae, Larinioides cornutus. Frédéric Ysnel, Laboratoire d'Evolution des Systemes Naturels et Modifiés, URA 696 du CNRS, Campus de Beaulieu, Université de Rennes I, 35042 Rennes Cedex, France; 8 March, 1993. Among the many studies already carried out about the trophic spectrum of the araneids (Nentwig, 1987), some suggest that the popula- lion of spiders—wandering spiders or non-migrant spiders—can utilize a significant proportion of the secondary productivity of natural areas (Kajak, 1967; Robinson and Robinson 1970; van Hook, 1971; Blandin and Celerier, 1981; Nyffeler, 1952). Moreover, some studies emphasize that the growth increment (Vollrath, 1988), the rate of reproduction (Riechert, 1974; Wise, 1979) or the density of individuals (Kajak, 1977) observed in the populations can fluctuate with the number of prey caught. Thus, the charactenstics of popula- tion dynamics of spiders partly depend on the quantity of prey captured; they can give data about the secondary productivity and conse- quently about the biological resources of natural biotopes. However, no study has been done in temperate climates to link the characteristics of population dynamics of spiders with the quantity or the quality of trophic resources. My work on Larinioides cornutus (Clerk, 1758) (Araneae: Araneidae) (Ysnel, 1989) describes demographic evolution and reproduction rate of a population in a mesophilous heathland in western France (Ysnel, m press). Besides this, laboratory studies showed a thermal dependance between spider size and food intake (Ysnel, 1990). This study attempts to combine previous results to estimate the number of prey captured by a natural pepula- tion of spiders during its development. MATERIALS AND METHODS This study is based on the calculation of the energy intuke during the postembryonic develop- 688 44.60) tl I 125) lz [ies [go Fi? _Jarn.a5.as0.3) [12 | ne c= ane BT tae ker = 097) CG (jeutes) 4 wes 2 C+ Al EE aga (= 4h, = 0,44) a i ae C = lass oe Flt ? (n= 02, r= 095) f ony 2pe ee } (ne 50, 7 © Hab LPIV (rm) FIG. 1. Theoretical relationship between spider size and consumption in intermoult periods (n = no, of measurements, r= correlation coefficient). ment of L. cornutus. To estimate energy require- ments during juvenile development, I refer to results on the individual energy consumption of spiders at different temperatures (Ysnel, 1990); thus, only the main references of the experimental conditions are described. Young spiders from cocoons reared in the Jaboratory were divided into three groups. by temperatures-16.5°C, 21°C and 26°C. (These values are a little lower than those in my previous work; they agree with more accurate values using an electronic ther- mograph). Spiders required a varied diet for sur- vival therefore they were reared to maturity using three prey species: the first instars were fed with adult Drosophila melanogaster and the last in- stars were fed with calliphorid flies (Calliphora hh ls _[sosscas5) | te fat6 70269) fia feseeazee [12 [rs0a78) | usais [is [ose fe fat 333,90 (86,27) fo [rssv.a aoa) [7 [991s cris) [12 |6a7.70c066.65) [3 [6s8.39(22.55) | SF STE 1029.6 MEMOIRS OF THE QUEENSLAND MUSEUM [7 |12,7003.3)__| | 28.74 (13.97) TABLE 1: Average values of consump- tion (C, joules) during each juvenile instar, (n = number jp _|s9s c1s6.s6) _| of individuals tested, SD = stand- 2581.5 ard deviation), c {loules) aie ay ta 7335 on FIG. 2. Pseudo-cubic spline showing relationship be- rween spider size (T PIV), consumption in intermoult period (C) and air temperature (T°C). vomitaria and Lycilia sericata). Three times a week, all spiders received a fixed number of prey according to their age. Juvenile spiders were kept under a light regime of LD 12:12. Furthermore, 8 spiders collected in the field at stages 4 and 6 and were reared in the laboratory at 13°C. For these spiders, the energy consumption was studied after the first moult in captivity. As adults, only females feed (adult males no longer build webs). In nature, females can mate in autumn but egg-laying occurs only under long days from May to August. During this period, females lay, on average, only one egg-sac and disappear soon after laying (Ysnel, in press). Therefore, energy consumption is estimated in 0.27 £0.033 TABLE 2. Average lengths of tibia TV (T, mm) and comparison of 26°C KW. | T+S5D 0.270.026 | P<0.7 040+0,043 values for 16.5°C, 21°C 0,37 £0,032 ae ia |- eo, foots fan 0.86+0.13 1.6340.237 1.21 £0,143 [3 |1.34+0.04 fe and 26°C, (n = no. of measurements, SD = standard deviation K.W. = Kruskall- Wallis test). 0.58 +000 9 |1.42#0.27 RELATIONSHIP BETWEEN FOOD INTAKE AND SPIDER SIZE 689 21°C TABLE 3, Consump- tion of Gand no, of eggs /cocoons al 3 temperatures, (T = length of tibia 4; N] = no. eggs/first egg- sac; C=energy intake by / in joules; C/egg =energy intake for Cleg Imi fe [crege [rece ite [Hn assess as [ar fw oa oa [7 law foe loan in [aw [vrs fen | Tie ff rn foe o_| feats ak fiat tat ens an pro-duction of } pra. 723.31 | 0.05 C Unules) 1500 Te C= -W467 + 825.25 T (r= 0.04 5 P's 0.0102) FIG. 3 energy (C) required to elaborate first egg-sac. . Relationship between size of females (T) and adults based on the energy intake needed to produce one cocoon. With this aim, 22 over- wintering fecund females were collected and reared in the laboratory under long days (LD = 16 : 8) and different temperature conditions (13°C, 16.5°C, and 21°C). After the females oviposited, we determined the relationship between the ener- gy intake, the female size (Iength of tibia 1V) and the number of eggs per cocoon. For each juvenile instar and the adult, the ener- gy intake was determined by the difference be- tween the energy in the whole captured prey and that in the food remains. Calorific determinations for all prey and food remains were made using a Parr bomb calorimeter (Ysnel, 1990), From the phenology of different instars in na- ture, the developments of the species have been worked out (Ysnel, in press), Spiderlings emerg- ing trom egg sacs laid from late spring to early summer become adult before winter and form a first cohort of individuals (cohort C1). Spiderl- ings which appear later (end of summer) form a second cohort in the population (cohort C2); they are still immature in winter and become adults early next summer. In analysing the demographic evolution of the population (from 20 m- sample areas) during the life cycle, the number of surviv- ing spiders per instar was counted for the two 2.02 ee = (AY N=~ Dida + 14401 1 (after YSNEL, in press) N (21M =~ (R96 + 152.507 3 laboratory cata (2) * fects (1) ire 0,82, P< 0,007) yoo 15 ea 22 2.4 zo FIG. 4. Relationship between no.of eggs (N) produced in first cocoon and size (T) of females, cohorts (Ysnel, 1992). For each juvenile instar, the energy consumption was inferred from the average size of spiders (length of tibia TV) and the thermal environment in the field, Daily meteorological data were classified in four temperature classes (T< 16°C; 16,5°C 22°C) and the average value of each class calculated. The energy in- gested is determined from the relative proportion of each phase of temperature during one inter- moult period. The average value of the caloric Cl epe 0) Cregg = 74,014 - 67795 T fr2=Op6, Hygrolycosa; Xerolycusa; ’ Evippa. shape of epigyne and tegular apophysis, by the profile of carapace (cf. Kroneberg, 1875, pl. IV, fig. 28; Pocock, 1889, pl. XIII, fig. 1), as well as by relatively larger PME and PLE, presence of only 2 teeth at the retromargin of chelicerae (in L. alticeps and L. medica 3), colouration of the ventral side of abdomen and smaller body length, The descendmg carapace in both sexes of Oculicosa supermirabilis, fur-like hairs at the edges of carapace, and the long and dense whitish hairs on the dorsal side of coxae indicate a bur- rowing way of life (see also Zyuzin and Zarko, 1989: Zyuzin, 1990), although I could not find the burrows of this species. Our investigations showed that carapace pubescence together with dense hairs on the coxae considerably diminish the friction between the coxae and the edges of carapace; in the much more active males these features are more pronounced and supplemented with many dorsal adpressed whitish-grey hairs on the carapace thus facilitating their movements in burrows. The role of carapace descent is as fol- lows. The comparatively long femora TI and TY | [yensinwe —YEvippinge | Pardosinae | Wadicosinae! |Venoninae? _[ Piratinae jy fees fa faz fan __fsuntipat_fa-st____ 2 otzsetdomes? bm feb seldom * | Fe ee [4 Jat; seldom a3 CE (TS sk eu es he seldom i3 io Cid is jo_{n_—_|n® pang’ _p__{p_{js_iyp___ [11 [its k5, usually k2;seldomk7> [k2 [kt vusually 2 [k3 kt |k5-K6; seldom k4 MEMOIRS OF THE QUEENSLAND MUSEUM 9. Male palp, bed of tip of resting embolus: i1, small tegular depression: i2, enlarged tegular depression; i3, deep dor- sal channel of TA; i4, tegular depression on upper tegular process; 15, deep ascending fegular groove 10. Male palp, character of conductor; j1, deep dorsal transverse channel of TA; j2, deep dorsal longitudinal channel of TA; }3, thick well-sclerotized basal part of palea concealed by tegulum; }4, opened (free) transverse sclerotized lateral process of the basal part of palea; j5, opened large apical; }6, combined with embolus (single complex) 11. Bpigyne: kl, variable; k2, median inverted T-shaped plate; k3, entire plate with 2 parallel oblong grooves above; kd, simple entire plate; k5, simple hairy plate; k6, hairy plale with lateral sclerites; k7, posteriorly protrad- ing hairy plate ' Wadicosa; * afer Lehtinen & Hippa, 1979; * Hippasa; press aguinst the carapace when moving in nar- row burrows: the length of femur IV is slightly longer than the carapace slope. Long-legged males of burrowing lycosids very often have a low flattened carapace (as well as females of the genus Lycosa s. str., €.g. Lycosa tarantula and L. nordmanni: see Zyuzin, 1990): this compensates for the lack of descent, favilitates the folding of very long femora and improves the mobility of these spiders. I sug pgest thatthe strongly descend- ing carapace not only in females but also in males {as in Oculicosa), together with comparatively narrow carapace, indicates the burrowing way of life from the early juvenile stages up to their imaginal moult: therefore, the distribution of such species is probably very restricted. On the con- trary, in Lycesa nerdmanni and Allohogna sin- goriensis with their flautened carapace in males, mature females seem to be more or less burrow- ing. while the juveniles, especially early stages, are active. This feature undoubtedly facilitates aerial dispersion of juveniles: as.a result, both of these species are widely distributed, ANEW LYCOSID GENUS FROM KAZAKHSTAN AND THE TROCHOSINI PALPAL MORPHOLOGY Further discussion concerns the terms ‘conductor’ and ‘terminal apophysis’, as their interpretation by different authors is sometimes rather contradictory. ConbucTOR The tip of the resting embolus in both Par- dosinae (at least in Purdosa and Acantholycosa) and Lycosinae lies in the oblong depression of the tegulum: in Pardosinae this depression is rather small and spoonlike (Figs 9, 12}, while in Lycosinae it is enlarged, sometimes strongly, end usually forms the tegular lobe (Fig. 10; Dondale, 1986, figs 12, 13). In an unexpanded palp of Pardosinae the depression of the tegulum fully separates the embolus from the true (functional) conductor Which is the transyerse well- sclerotized groove situated near the base of the terminal part (shield, palea} of the genital bulb and almost fully concealed by the tegulum (Figs 9, 12). In mernbers of Lycosinae, the enlarged depression of the tegulum is regarded as the con- ductor of the embolus (see Dondale and Redner, 1979; Dondale, 1986), though this bed for the resting embolus does not fit to assist the exact movement of the embolus tip to the female copulatory opening. Lehtinen and Hippa (1979) white: ‘We are aware that “conductor” is not a very suitable name for the outer par of the Lycosid embolic division, because it is not al- ways a functional conductor’. Our investigations have shown that the deep transverse channel on the inner (dorsal) surface of legular apophysis opened at its narrow distal end and diagnostic for all members of the subfamily Lycosinae (Don- dale. 1986) is intended for the embolus and un- doubtedly directs its tip to the copulatory opening: thus, the TA of Lycosinae serves as the functional conductor. The mechanism of opera- lion of such a conductor during copulation is shuwn in Alopecosa cuneata (Clerck) (Fig. 5): while the hooked ventral spur of the TA comes into contact (forms a hook-up) with the anterior pockets of the epigyne, the ventral rib of the ‘hook’ enters the longitudinal epigynal groove, se that the channel opening lying at the distal end of TA comes into proximity with the copulatory opening of the epigyne. Above the embolus and behind the TA in many species of Lycosinae is situated a narrow, shur- pened Jaminar process (see Figs 6-8) usually slightly grooved on its ventral side: the proposed nume for this laminar process of palea in 697 Lycosinae is “synembolus', as it always accom- panies the embolus and has the same chrection. | suppose that the embolus dunng copulation enters the TA channel together with the laminar synembolus which directs the embolus to the channel and probably locks the lust as a stopper, fully excluding the deviation of the embolus, Thus, the synembolus plays the role of auxiliary conductor, In species of the Alopecosa jpul- verulenia group the synembolus ts fused with the base of the palea, so that only an ectal tooth remains at its external side: in this case all the base of the palea goes to the wide ‘“antechamber™ before the channel. Dondale (1986) correctly regards the subfamily name Hippasinae to be a junior synonym of the Lycosinae. In representatives of the genus Hip- pasa TA also serves as the functional conductor! despite the Jack of an atrium in some Aippasa species (e.g. Hippasa deserticola Simon, and H. cinerea Simon) and the agelenid habit of the spiders, I regard them, as well as allied genera, to represent the tribe Hippasini Simon, stat. now. mn the subfamily Lycosinae (see Table 3). Besides the Lycosinae, the conductor is repre- sented by the tegular apophysis in two other subfamilies: Evippinae (type: Evippa Simon) and Allocosinae (type: Allocesa Banks). 1. Evippinae. Members of this subfamily have a hooked longitudinal TA which somewhat resembles the transverse trochosoid ‘hook’ of Lycosinae. As in the species of Lycosinae, the members of Evippinae have a distinct channel on the inner (dorsal) side of TA and a pedicled septum widened posteriid (Zyuzin, 1985, figs 15, 16, 20-22), But, despite these similarities, the genera Evippu and Xerolyrosa have a number of features which allow them to be regarded ss members of the separate subfamily. Thus, the channe} on the dorsal side of TA in Evippinae is longitudinal (in all Lycosinae itis transverse); the whole embolus is situated in a deep depression and forms a very characteristic recurved flat loop; the base of embolus always has an apical position: the pulea is strongly reduced; and the epigynal grooves are very shallow and lie at the level of the septal pedicle. Resides, in Evippa spp. the synembolus is transformed into a narrow func- tional conductor which ts constantly sttuated in it channel of TA and projected beyond the TA limits: in this case TA serves as an auxiliary conductor, In Xerolycosa spp- the functional con- ductor is represented by TA: the embolus con- stantly Jies m a channel (see Zyuzin, 1985), the 698 MEMOIRS OF THE QUEENSLAND MUSEUM FIGS 9-12. Scanning electron micrographs: 9, 10, 12, genital bulbs dissected from cymbia; 11, palea with embolus and conductor dissected from genital bulb). 9, Pardosa sodalis Holm. 10, Hogna radiata (Latreille). 11, Pardosa chionophila L. Koch. 12, Pardosa turkestanica (Roewer). Abbreviations: con, conductor; dep, tegular depres- sion; emb, embolus; pl, palea; prp, process of palea; sem, synembolus; TA, tegular apophysis; term, terminal apophysis; ucon, upper branch of conductor. Scale bar=0.1mm. synembolus is strongly reduced and fused with the semi-transparent extension of the embolus. 2. Allocosinae. In Allocosa spp. TA is double- branched, the channel is situated on the dorsal side of the narrow basal branch and holds the tip of the resting embolus; and the atrium of the epigyne is lost (see Dondale and Redner, 1983; Dondale, 1986). Besides, the basal part of the pardosoid palea probably serves as an auxiliary conductor directing the embolus into the channel of TA in the expanded palpus. In the genus Pirata and allied genera (Piratula, Aulonia, Hygrolycosa) the functional conductor is combined with a short thin embolus in a com- A NEW LYCOSID GENUS FROM KAZAKHSTAN AND THE TROCHOSINI mon sickle-shaped complex resting in a deep and narrow ascending tegular groove. The distal posi- tion of the well sclerotized conductor in repre- sentatives of the subfamily Venoniinae (Venonia and allied genera: see Lehtinen and Hippa, 1979) does not allow us to include Pirata in the sub- family Venoniinae, as Dondale (1986) did. Pirata and allied genera probably deserve to be included in the separate subfamily Piratinae (type: Pirata Sundevall, 1832) (see Table 3). TERMINAL APOPHYSIS Very often the palea in Pardosinae (at least in Pardosa and Acantholycosa) above the embolic division is supplied with a stout, very sclerotized process: many authors (e.g. Holm, 1947; Ton- giorgi, 1966; Kronestedt, 1975) designate this process as the terminal apophysis. Dondale (1986) writes *... the terminal apophysis ... is believed to assist the finding and penetration of the copulatory opening by the embolus tip’. It is therefore obvious that, to play this very important role, the terminal apophysis must be situated im- mediately above the end of the conductor (Figs 9, 11; Kronestedt, 1975, fig. 3); sometimes the den- tiform terminal apophysis is situated directly at the outer part of the conductor (see Dondale and Redner, 1984, figs 21, 25, 26). At the same time, there are many cases when the much larger paleal process is situated far above the conductor, i.e. so that it cannot assist the exact penetration of the embolus tip into the female copulatory opening (Fig. 12); however, such a process is also wrongly designated as the terminal apophysis (see Lowrie and Dondale, 1981, fig. 10; Dondale and Redner, 1984, fig. 5; Dondale, 1986, fig. 7). Tongiorgi (1966, fig. 1) correctly designates the true ter- minal apophysis and the laminar process: the destination of such a process is otherwise, e.g. to protect the resting embolus, or to make an engagement during copulation. An incorrect designation of terminal apophysis is also used by Buchar (1976, figs 7, 8): in his fig. 8 it is a mere tubercle of the palea, while in fig. 7 (Pardosa thaleri) this author confuses it with the narrow laminar conductor sharpened at the tip and characteristic for the Pardosa bifasciata group. The, similar conductor shape, also desig- nated as the terminal apophysis, is in the species ‘Pardosa’ oncka Lawrence (see Kronestedt, 1987, fig. 4C). In some works the synembolus of Lycosinae is also called the terminal apophysis (see Dondale and Redner, 1979, 1990; Dondale, 1986). But, as the synembolus only directs the embolus to the 699 channel of TA (see above), the role of the true terminal apophysis is fulfilled by the ventral process(es) of TA fixing the last on the female epigyne. The designation of the ectal tooth of palea in the Alopecosa pulverulenta group as the terminal apophysis (see Kronestedt, 1990) is also incorrect: actually this tooth is the synembolus (see above). Formerly (see Zyuzin, 1990), I restricted the Lycosini to burrowing lycosids only, and erected the new tribe Trochosini for non-burrowing genera of Lycosinae. Herein the structure of both these tribes is revised: thus, I include in Trochosini only those genera that are charac- terized by the very peculiar TA which has a transverse lamella with a ventrally directed trochosoid ‘hook’, or spur, and the epigynal sep- tum with a distinct narrow pedicle, widened posteriad, very often in the shape of an inverted ‘T’; epigynal grooves on either side of septal pedicle are rather deep and distinct. Both non- burrowing and burrowing lycosids are included in this very large tribe, undoubtedly having a common origin; in accordance with this view the tribe Trochosini is divided into two subtribes: Trochosina Zyuzin, stat. nov. (including the non- burrowing genera Trochosa, Alopecosa s. str., Hognas. str., Schizocosa), and Geolycosina, sub- trib. nov. (including the burrowing genera Arctosa s. str., Geolycosa, Allohogna with a very characteristic carapace profiles: see Zyuzin, 1990, fig. 1). There are many species throughout the world, including African ones, which also belong to the Trochosini: the generic and sub- tribal position of these remain obscure due to the artificial system of Roewer (1959-1960). As shown in Fig. 5, the length of the epigynal groove and septal pedicle in species of Trochosini is correlated with the length of the ventral spur of TA. As to the tribe Lycosini, I place here only the members of Lycosa s. str. with their very peculiar genitalia, and some allied species referred to ‘Allocosa’, ‘Hogna’ and probably Metatrach- osina (Roewer, 1959-1960, figs 124, 126, 129, 219, 304-305, 517). ACKNOWLEDGEMENTS For the loan of material and necessary technical assistance I am very grateful to the following persons: Dr Ch. Deeleman-Reinhold (Os- sendrecht, The Netherlands); Dr C.D. Dondale (Ottawa, Canada); Mr S.I. Ibraev (Alma-Ata, Kazakhstan); Drs D.V. Logunov (Novosibirsk), 700 Y.M. Marusik (Magadan) and K.G. Mikhailov (Moscow) (all Russia), For the kindly given pos- sibility of use the scanning electron microscope im my work Lam very thankful to Dr V.K. Lebsky and Mr V.M, Semyonovy (St. Petersburg. Russia). I am also indebted to Mr K.N, Plakhov (Alma- Ata), who organized the scientific trip to Man- gyshlak and Ustyurt Plateaus. LITERATURE CITED BUCHAR, J, 1976, Uber cinige Lycosiden (Araneae) aus Nepal. Khumbu Hinial 5: 201-227. CHARITONOV, D.E. 1932. Katalog der Russischen Spinnen, Beilage zum Annuaire du Musée Zoologique, Leningrad, 32. 206pp. DONDALE, C.D. 1986, The subfamilies of wolf spiders (Araneae: Lycosidae). Actas del X Con- greso Aracnologico, Jaca, Espatia, vol. |: 327- 332. DONDALE, C.D & REDNER, J... 1979. Revision of the wolf spider genus Alopecosa Simon in North America (Araneae: Lycosidae). Canadian En- tomologist 111; 1033- 1055, 1983. The wolf spider genus Allocese in North and Central America (Araneae. Lycosidae). Canadian Entomologist 115; 933-964, 1984, Revision of the milvina group of the wolf spider genus Pardosa (Araneac: Lycosidie). Psyche 91: 67-117. 1990, The wolf spiders, nurseryweb spiders, and lynx spiders of Canada and Alaska (Araneac: Lycosidac, Pisauridac, and Oxyopidae). The In- sects and Arachnids of Canada 17. 383 pp. (Agriculture Canada: Ottawa). DUBININ, V.B. 1946. [Inhabitants of mammal holes in South-Khazakhstan Area and their significance for man]. Izvestija Akademii Nauk Kazakhskoj §.S.R., Parasitological Series 4: 93-102. [in Rus- sian, HOLM, A. 1947. Egentliga Spindlar. Araneae, Fam. 8-10, Oxyopidac, Lycosidae och Pisavridae, Svensk Spindelfauna vol. 3, 48 pp. KRONEBERG, A. 1875. Araneae, In: Feditschenko, A.P. Reise in Turkestan, Zoologischer Theil 2: 1-38. KRONESTEDT, T. 1975. Studies on species of Holarctie Pardosa groups (Araneae, Lycosidae), L. Redescription of Pardasa albomaculata Emer- ton and description of two new species fram North America, with comments on some taxonomic characters, Zoologica Scripta 4: 2) 7-228. 1987. On some African and Oriental wolf spiders (Araneae, Lycosidae): redescription of Pardosa MEMOIRS OF THE QUEENSLAND MUSEUM oncka Lawrence from Africa, with notes on its generic position. Journal of Natural History 21: 967-976, 1990, Separation of two species standing as Alupecosa aculeata (Clerck) by morphological, behavioural and ecological characters, with remarks on related species in the pulverulenta group (Araneae, Lycosidae). Zoologica Scripta 19: 203-225. LEHTINEN, P.T. & HIPPA, H. 1979, Spiders of the Oriental-Australian region. 1, Lycosidae: Venoniinae and Zoicmae. Annales Zoologici Fen- nici 16: 1-22. LOWRIE, D.C. & DONDALE, C.D. 1981. A revision of the nigra group of the genus Pardosa in North America (Araneae, Lycosidae). Bulletin of the American Museum of Natural History 170): 125- 139. MARIKOVSKIJ, P.I. 1956. [Tarantula and karakurt. Morphology, biology, toxicity], (Academy of Sciences of Kirghiz $.S.R.: Fronze). 281 pp. [in Russian} POCOCK, RI, 1889. Arachnida, Chilopoda and Crus- tacea, In: Aitchison, J.E.T. The Zoology of the Afghan Delimitation Commission. Transactions a ay dala Society of London (2) 5, Zoology: -121. ROEWER, C.F. 1959-1960, Araneae Lycosaeformia Il (Lycosidae). Exploration du Parc National de ! Upemba, Mission G.F, De Witte, fascicule 55. Institut des Parcs Nationaux du Congo Belge, 1040 pp. (Bruxelles). SCHMIDT, P. 1895. Beitrag zur Kenntniss der Laufspinnen (Araneae Ciligradae Thor.) Russlands, Zoologische Jahrbiicher, Abteilung fiir Systematik 8: 439-484, TONGIORGI, P. 1966. htalian wolf spiders of the genus Pardosa (Araneae; Lycosidae), Bulletin of the Museum of Comparative Zoology 134: 275-334. ZYUZIN, A.A. 1985. [Generic and subfamilial criteria in the systematics of the spiders family Lycosidae (Aranei), with the description of anew genus and two new subfamilies]. Proceedings of the Zoological Insite, Leningrad 139; 40-51. [in Russian] 1990, Stadies on burrowing spiders of the family Lycosidae (Araneae). 1, Preliminary dala on structural and functional features. Acta Zoologica Fennica 190; 419-422. ZYUZIN, A.A. & ZARKO, M.¥V. 1989. The structural and functional features of digging spiders of the family Lycosidae (Araneae). In: X1 International Congress of Arachnology, Turku, Finland, 7-12 August, 1989. Abstracts, Reports from the Depart- ment of Biology, University of Turku 19: 1 16. CONTENTS (continued) J R. er “We'll meet again", an expression remarkably applicable fo the historical biogeography of Australian Zodariidae (Araneae)... 02 ee ene ence teen tae en eeee 564 KONDO, A., CHAKI, E. & FuxubA, M- Basic architecture of the ovary in the golden silk spider, Nephila clavata ,......... a bets beeetets 565 KOOMEN, P, & PEETERS, T.M.J. New prey records for:spider hunting wasps (Hymenoptera: Pompilidae) from The Netherlands .....,. 571 KOPONEN, S. Ground-liying spiders (Araneae) one year after fire in three subarctic forest types, Québec (Canada) .. 575 Kraus, O. & KRAUS, M. Divergent transformation of chelicerae and original arrangement of eyes in spiders (Arachnida, Araneae). ......... eae attend olastalet ech Witton tated ead piles eles etlys 579 LEHTINEN, P.T. Polynesian Thomisidae - a meeting of old and new world groups ............-.--.--+--+-+++-+- 385 LOCKET, N.A. Scorpion distribution in a dune and swale mallce environment .......... nite ees PCE oc 5 OT CT S| MAIN, B.Y. From flood avoidance to foraging: adaptive shifts in trapdoor spider behaviour ............:....0. 599 Marc, P. Intraspecific predation in Clubiona corticalis (Araneae; Clubionidae) ............ aot steams Boe St 3 8 607 MULLER, M.C. & WESTHEIDE, W. Comparative morphology of the sexually dimorphic orb-weaving spider Argiope bruennichi (Araneae: Araneidae) ..........-..-206- triimgass tes pep ety Delt Mn ig Fal oa shal ae 615 PLATEN, R. A method to develop an ‘indicator value” system for spiders using Canonical Correspondence Analysis (CCA) 0... cece cece eee ev eee ee ee eee ues ater see ba Legit tage tel alae a) 621 ROLLARD, C. ; The spiders of the high-altitude meadows of Mont Nimba (West Africa): a preliminary report ....... 629 ROvNER, J.S. Visually mediated responses in the lycosid spider Rabidosa rabida: the roles of different pairs Of eyes 2... eee eee eee ee eee e eb eb eed eet eebenbeetes 635 SUNDERLAND, K.D, & TOPPING, C.J. The spatial dynamics of linyphiid spiders in winter wheal ....-...0..0.0 000000 ce eee eee eee eee 639 SUZUKI, H. & KONDO, A. Morphology of the embryos at germ disk stage in Achaearanea japonica (Theridiidae) and Neoscona nqutica (Araneidae) 2.2... oo cee ene eens 645 TARABAEV, C.K. An experiment on colonization of karakurt (Latrodectus tredecimguttatus, Black Widow spider) on island territories in Kazakhstan ........ 2220: e se cee eee cece tee eee 651 TARABAEV, C.K., ZYUZIN, A.A. & Frvoporoy, A.A. Distribution of Latrodectus (Thendiidae), Eresus and Plebedypins (Eresidae) in Kazakhstan and Central Asia ....... meee ee Po ease gee Pesy fee Seteeeateserdesde dba de seer sed 683 TsURUSAKI, N. Geographic variation of the number of B-chromosomes in Metagagrella tenuipes (Opiliones, Phalangiidae, Gagrellinae) ......... 00. eee pee eee eer pecs eee eee see nn ee OSD UHL, G. Mating behaviour and female sperm storage in Pholcus phalangioides (Fuesslin) (Arancae) ......... 667 Wishakt, G,F.C. The biology of spiders and phenology of wandering males in a forest remnant (Araneae: Mygalomorphae) -, 2... ce eee eee een eee ee 675 WUNDERLICH, J. The Macaronesian cave-dwelling spider fauna 20... 0.0). ccc epee en eee eee beet t eben beete 681 YSNEL, F, Relationship between food intake and spider size in temperale zones: experimental model for an orb-weaving spider . 2.2.2... 00.022, -405 petit ge gd bogey beet ee toed te pesd Se pe 687 ZYUZIN, A.A. Studies on the wolf spiders (Araneae: Lycosidae)_ 1. A new genus and new Species from Kazakhstan, with comments on the Lycosinae ....,. Chale ree ew orale pistatee teat lett hed CONTENTS INVITED PAPERS SELDEN, P.A. Fossil arachnids—recent advances and future prospects .... 2... ..0.0000ceccccucseccctcacecceees 389 POLIs, G.A., Scorpions as model vehicles to advance theories of population and community ecology: the role of scorpions in desert commumities .........0..00.ccccerceccrecceaccencsencend 401 ELGAR, M.A. Inter-specific associations involving spiders: kleptoparasitism, mimicry and mutualism ............. 411 CONTRIBUTED PAPERS AbIS, J, & MAHNERT, V. Vertical distribution and abundance of pseudoscompions (Arachnida) in the soil of two different neotropical primary forests during the dry and rainy seasons ....................2% 431 AUSTIN, A.D. Nest associates of Clubiona robusta L. Koch (Araneae: Clubionidae) in Australia .................. 441 BaerT, L. & Jocqué, R. A tentative analysis of the spider fauna of some tropical oceanic islands. ................0020.000% 447 BENTON, T.G. The reproductive ecology of Euscorpius flavicaudis in England ...............0-0.0ceceuescuses 455 CANARD, A. & STOCKMAN, R. - Comparative postembryonic development of arachnids ..............0..0cceeecsesscccececencs 461 CaTLey, K.M. Courtship, mating and post-oviposition behaviour of Hypochilus pococki Platnick GA Tar rita ERGOT oe lg veep ee peed ee evry oad» Sum opie ndlyig De wacvarb agra atd-ealewe-e nels 469 CHURCHILL, T.B. Effects of sampling method on composition of a Tasmanian coastal heathland spider assemblage .... . 475 DAVIES, V. Topp. A new spider genus (Araneae: Amaurobioidea) from rainforests of Queensland, Australia ........... 483 DEELEMAN-REINHOLD, C.L. An inventory of the spiders in two primary tropical forests in Sabah, North Borneo ................. 491 Durrey, E. A review of factors influencing the distribution of spiders with special reference-to Britain........... 497 EDMUNDS, J. The development of the asymmetrical web of Nephilengys cruentata (Fabricius) .................+- 503 ‘EDMUNDs, M. Does mimicry of ants reduce predation by wasps on salticid spiders? ..............0-0.00ceeeeeecs 507 FAIRWEATHER, P.G. Abundance and structure of fossorial spider populations .............0.-2-0ccccceccccceccccucs 513 GILLESPIE, R.G, Biogeographic pattern of phylogeny in a clade of endemic Hawaiian spiders (verdana: Veiba ee MMT 8 ts 0x79 OTT xy tes 2 Sa Md Ee cocs TE ahine a, g.te: Rtsars Aokss4-ctghee thee e.g 519 GRoMoV, A.V. A new species of Karschiidae (Solifugae, Arachnida) from Kazakhstan ................00.0se0eee 527 Hirst, D.B. A new species of Amaurobioides O.P.-Cambridge (Anyphaenidae: Araneae) from South Australia .. . .529 HorMIGA, G. Implications of the phylogeny of Pimoidae for the systematics of linyphiid spiders (Araneae, Araneoidea, Linyphiidae) ..,.... 0.00.20. 0ccceneceveccccucenerseveevensenes 533 HuMPuREYS, W.F. Criteria for identifying thermal behaviour in spiders: a low technology approach ................... 543 Hunt, G.S. & Maury, E.A. Hypertrophy of male genitalia in South American and Australian Triaenonychidae (Arachinda: Opiliones: Laniatonesy