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Full text of "The ants of Rennell and Bellona Islands."

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33. THE ANTS 
OF RENNELL AND BELLONA ISLANDS 

BY 

EDWARD O.WILSON 

MUSEUM OF COMPARATIVE ZOOLOGY, HARVARD UNIVERSITY, 
CAMBRIDGE, MASS., U.S.A. 

The ant fauna of Rennell Island and its small neighbor, Bellona Island, was completely 
unknown until 1934, when W. M. WHEELER listed several species collected by MAURICE 
WILLOWS, Jr., during the Templeton Crocker Expedition of 1933. The picture is now 
considerably strengthened by the addition of the material to be reported upon in the 
present paper. This material comes from three sources : the Danish Expedition (Dan. 
Exp.), which as a subsidiary enterprise of the Galathea Expedition Round the World 
1950-52, stayed on Rennell Island from 12 October to 14 November, 1951, under the 
direction of Dr. TORBEN WOLFF (WOLFF, 1955a and 1955b); a British expedition (Brit. 
Exp.) conducted on Rennell Island from 15 October to 27 November 1953 by Mr. J. D. 
BRADLEY and Mrs. DIANA BRADLEY under the auspices of the British Museum (Natural 
History) (BRADLEY 1955); and a private collection made on Rennell and Bellona dur- 
ing November 20-30, 1955, by Mr. E. S. BROWN. The Danish collection is deposited in 
the Zoological Museum of Copenhagen and the Bradley and Brown collections in the 
British Museum (Natural History). The author wishes to express his appreciation to 
these institutions and to the collectors mentioned for the opportunity of studying this 
valuable material. 

The basis of our present knowledge of the ants of the Solomon Islands as a whole 
is the monograph published by W. M. MANN in 1919. This is an unusually sound and 
thorough work of its kind, partly because MANN collected in the islands himself, from 
19 May to 24 November 1916. An entertaining account of his experiences during these 
early and difficult times is given in his well-known autobiography, "Ant Hill Odyssey". 
More recently, the present author has been revising the ants of the Solomons as part 
of a larger study of the Melanesian fauna (WILSON, 1958 and 1959 a). The available 
collections from the main islands of the Solomons have been growing rapidly, thanks 
largely to the collecting program of the B. P. Bishop Museum, Honolulu, under the 
direction of J. L. GRESSITT. 



13 



THE ANTS OF RENNELL ISLAND 

SUBFAMILY PONERINAE 
Trachymesopus stigma (Fabricius) 

Record: Lavanggu (Dan. Exp. L357); cultivated area with Carica Papaya, on decay- 
, ing wood and on and in ground. The single worker was probably collected in a rotting 
log, the preferred if not exclusive microhabitat of the species in the remainder of 
Melanesia. 

T. stigma is one of the most widespread of all ponerine species. It is found both in 
the New World and Old World tropics; in the latter it occurs from southern China to 
Queensland, Micronesia, outer Melanesia, and Samoa. As noted elsewhere (WILSON, 
1858), there does not appear to be any significant geographic variation over this vast 
range. In both hemispheres stigma has been collected from the interior of relatively 
undisturbed native forests, where it lives in apparent compatibility with local endemic 
faunas of the most diverse kinds. Its ultimate origin is unknown, but the New World 
tropics seem the most likely possibility, since the most closely related species occur 
there. Perhaps it was introduced by man into the Old World and has thrived by virtue 
of its choice of nesting site. I have already shown (1959 c) that in New Guinea it is a 
member of a small, ecologically isolated group of species that are mostly limited in 
their activities to larger rotting logs in intermediate stages of decomposition. 

Leptogenys ?foreli Mann 

Record: Hutuna (Brit. Exp.); Te-Uhungango (Brit. Exp.). Two males are tentatively 
identified as either foreli Mann or the closely related truncata Mann. Males have never 
been associated with either of these species, but the Rennell specimens correspond 
closely in size, sculpturing, and petiole form to the worker caste. Of the two possibili- 
ties,/^// is the more likely, since it is known to range widely from New Guinea to the 
New Hebrides, while truncata is known only from the type collection..frQ_mJ:he Santa 
Cruz islands. 

Odontomachus simillimus Fr. Smith 

Records: Lavanggu (Dan. Exp. L352, L356, L357, L372, L374, L390); Niupani 
(Dan. Exp. L378, L385; Brit. Exp.); Te-Avamanggu (Dan. Exp. L364, L365); Hu- 
tuna, worker and four males (Brit. Exp.). The large number of records suggests that 
simillimus is one of the more abundant species on Rennell. It was collected in a wide 
array of habitats : sandy grass-plain near shore, open cultivated places, low vegetation 
near lake, young forest (about 3 m. high) on previously cultivated area, and rain 
forest. This is also an extremely abundant and versatile species elsewhere in Melanesia 
(WILSON, 1959a). WHEELER (1934) has previously recorded it from Kanggava Bay 
(Lavanggu?), Rennell I., and the northwest end of Bellona Island. I have also seen 
workers collected on Bellona by E.S. BROWN in 1955. 

1 4 



O.simillimus is the most widely distributed of all Indo- Australian ponerine ants, 
ocurring through most of tropical Asia and the Pacific Region. It does not appear to 
show significant geographical variation. 

Odontomachus ?malignus Fr. Smith 

Record : Te-Uhungango, 3 males (Brit. Exp.). Three large, yellow Odontomachus males 
have been tentatively identified as this species. The only members of the genus known 
from the Solomon and Santa Cruz Islands besides simillimus are emeryi Mann and 
malignus Fr. Smith. Males have never been associated with workers in either case. Of 
the two, malignus has the wider distribution, being the only one to reach the Santa 
Cruz Islands, and its ecological range ideally suits it for the colonization of smaller 
islands (WILSON, 1959 a). Moreover, the Te-Uhungango males are closer to the pre- 
dicted size for malignus than they are for emeryi. 

Cerapachys inconspicua Emery 

Record : Hutuna (Brit. Exp.). A single male compares well with definitely determined 
specimens from the lower Busu River, New Guinea. C. inconspicua is the most wide- 
spread member of the genus in Melanesia, ranging from Netherlands New Guinea to 
the eastern Solomons. 

?Cerapachys (Syscia) sp. 

Record: Te-Uhungango, male (Brit. Exp.). A single specimen has been placed tenta- 
tively in Syscia. Unfortunately, no males of this subgenus have ever been associated 
with workers, but the specimen at hans is in or close to Cerapachys and seems to show 
modifications in body form similar to those in the Syscia worker caste. Only one 
species of Syscia, pawa Mann, has been recorded from the Solomon Islands. 



SUBFAMILY MYRMICINAE 
Pheidole oceanica Mayr 

Records: Hutuna (Brit. Exp.); Te-Uhungango (Brit. Exp.); Tingoa (Brit. Exp.). Minor 
workers and soldiers. This species ranges, with little or no significant geographic 
variation, from New Guinea northward into Micronesia and eastward through Me- 
lanesia (including New Caledonia) across Polynesia as far east as the Marquesas. It 
may be native to most or all of this range. In evidence is the fact that the distribution 
is continuous but strictly limited westward by New Guinea and eastward by the Mar- 
quesas. Also, its closest relative is P. impressiceps Mayr, which is undoubtedly native 
to New Guinea. 



15 



Pheidole umbonata Mayr 

Records: Hutuna (Brit. Exp.); Te-Uhungango (Brit. Exp.); single queens; Lavanggu 
(E. S. BROWN). Minor workers and soldiers. This little species occurs continuously 
from New Guinea to Micronesia, through outer Melanesia, and into Polynesia as far 
east as the Society Islands. Geographic variation has been noted in size and colora- 
tion, especially in the soldier caste. The Lavanggu series conforms to the central 
Melanesian populations in these two characters. 

Tetramorium pacificum Mayr 

Record: Hutuna (Brit. Exp.). WHEELER (1934) also records the species from the north- 
western end of Bellona Island. 

T. pacificum ranges widely through tropical Asia and the Pacific, as far east as the 
Society Islands. There is little or no significant geographic variation within this great 
range. 

Tetramorium tonganum Mayr 

Record: Te-Uhungango (Brit. Exp.). A single, headless alate queen probably belongs 
to this species. Tonganum occurs more or less continuously from New Britain to east- 
ern Polynesia and is probably native to most or all of this range. 

Monomorium destructor (Jerdon) 

Records: Tingoa (Brit. Exp.); Lavanggu (E. S. BROWN). This species is a pantropical 
tramp probably originating from tropical Asia. It occurs sporadically in the Pacific 
Region, e.g., on New Guinea and Rurotonga. The present record is the first from 
any part of the Solomon Islands. 

Vollenhovia oblonga (Fr. Smith) 

Records: Hutuna (Brit. Exp.), winged queen; Lavanggu (Dan. Exp. L372), winged 
queens, from rain forest. This is the most widely distributed species of Vollenhovia, 
occurring from Indonesia to the New Hebrides and New Caledonia. The Rennell 
queens do not differ significantly from several specimens of the same caste from Santa 
Cruz; no ther queen material was available for comparison during the present study. 
As noted by MANN (1919) in the Solomons and myself (1959c) in New Guinea, colo- 
nies normally nest under the bark of rotting logs in rain forest. 

Dilobocondyla sp. 

Record : Hutuna (Brit. Exp.) ; a single male. This is the first record of the genus from 
the Solomon Islands. The closest species geographically is cataulacoidea (Stitz) of New 
Guinea. Since the male of cataulacoidea is unknown, the position of the Rennell spe- 
cimen cannot be determined at this time. 

16 



SUBFAMILY DOLICHODERINAE 
Iridomyrmex cordatus (Fr. Smith) 

Records: Hutuna (Brit. Exp.), winged queen; Lavanggu (Dan. Exp. L372); worker 
from rain forest; Te-Uhungango (Brit. Exp.), winged queens. 

I. cordatus as presently conceived includes I.myrmecodiae Emery. The species is, 
next to I. anceps (Roger), the most widespread of the Old World Iridomyrmex. It oc- 
curs continuously from the tropical mainland of Asia to Queensland and east through 
the Santa Cruz Islands. The worker and queen castes show considerable geographic 
variation in several characters, including size, extent of polymorphism, and coloration. 
The single worker and small series of queens from Rennell resemble exactly the small, 
bicolorous form that makes up most of the Solomons and Santa Cruz populations. 

Turneria dahli Forel 

Record: Hutuna (Brit. Exp.), a single winged queen. The single individual presents a 
puzzling array of characters that seem to place it intermediately between dahli Forel 
and pacifica Mann but somewhat closer to the former species. It has been compared 
with queens of dahli from New Britain and pacifica from the New Hebrides (Espiritu 
Santo). These two samples differ as follows: (1) dahli has a somewhat more elongate 
head, with more acute occipital angles ; (2) dahli has at most one or two standing pairs 
on the sides of the head posterior to the eyes, whereas pacifica has numerous standing 
hairs in these areas; (3) in dahli vein Rs+4 is distinctly longer than the second radial 
crossvein, while in pacifica the two veins are equal in length; (4) dahli is concolorous 
dark brown, while in pacifica the gaster alone is dark brown, with the remainder of the 
body yellowish red. From collections recently acquired from several sources, it is now 
known that dahli occurs from New Britain to Espiritu Santo, and pacifica occurs from 
Santa Cruz to Espiritu Santo. Thus the two species are sympatric through the entire 
known range of pacifica. The Rennell specimen resembles dahli in characters (3) and 
(4) and pacifica in (2). It has the elongate head shape of dahli but more rounded occi- 
pital corners approching the condition of pacifica; thus in head shape it is somewhat 
closer to the New Britain dahli but in this respect is closely approached by dahli work- 
ers (no queens available) from Espiritu Santo. These morphological considerations, 
plus the fact that dahli is the most wide-ranging of all Turneria, have led to the present 
tentative determination of the Rennell specimen. It is interesting that no Turneria have 
yet been collected from the main part of the Solomon Islands, although the genus al- 
most certainly occurs there. It is evidently rare throughout most of its range, but on 
Espiritu Santo the author found dahli and pacifica to be among the dominant arboreal 
ants. A principal factor responsible for the unexpected success of the genus in the 
New Hebrides appears to be the lack of competitors found elsewhere in Melanesia, 
e.g., the genus Iridomyrmex. 



17 



Tapinoma melanocephalum (Fabricius) 

Record: Hutuna (Brit. Exp.). 

T, melanocephalum is a pantropical tramp species, possibly of Old World origin. 
It appears to have been introduced by man into Melanesia, where it is spottily distri- 
buted in cultivated areas. 

Technomyrmex albipes (Fr. Smith) 

Record : Hutuna, 2 males (Brit. Exp.). This is one of the most widespread of the Indo- 
Australian dolichoderines, ranging continously from tropical Asia to eastern Poly- 
nesia. 

SUBFAMILY FORMICINAE 
Anoplolepis longipes (Jerdon) 

Records: Hutuna (Brit. Exp.); Te-Uhungango (Brit. Exp.). This distinctive species, 
which is probably native to Africa, has been spread throughout the Pacific Islands by 
commerce. 

Paratrechina (Nylanderia) minutula (Forel) 

Records: Niupani (Dan. Exp. L385), a single dealated queen collected in low vegeta- 
tion near Lake Te-Nggano. Te-uhungango and Tingoa (Brit. Exp.), single males. This 
species has been recorded from many scattered localities in the Indo-Australian region, 
within the area bounded by Formosa, Western Australia, Lord Howe Island, Guam, 
and Samoa. Very possibly it has been introduced by man into part of its range. MANN 
(1919) records it from Ugi and Santa Isabel in the Solomon Islands. 

Paratrechina (Nylanderia) vaga (Forel) 

Records: Hutuna (Brit. Exp.), workers and males; Lavanggu (Dan. Exp., L351, 
L358, L359, L360, L374, L390), workers, dealate queen, and male: Te-Avamanggu 
(Dan. Exp., L364), worker; Te-Maingga (Dan. Exp. L362) workers; Te-Uhungango 
(Brit. Exp.), workers. This species is extremely adaptable. The Danish Expedition 
collected it from almost every principal habitat on Rennell, including the following: 
sandy beach, under leaves; coconut grove; secondary (3-m.-high) rain forest; mature 
rain forest. 

P. vaga occurs more or less continuously from Queensland and New Guinea east 
across the Pacific as far as Juan Fernandez. It is one of the most abundant ant species 
in Polynesia. The Rennell series show surprising internidal variation in total size, con- 
vexity of thoracic dorsum, density of pilosity, density of cuticular shagreening, and 
depth of color. This variation is nearly continuous, embracing none of the forms 
identical with other Nylanderia species known to be sympatric with vaga elsewhere ; 
hence all of the series have been placed here under vaga. It is probable that WHEELER'S 
(1934) record of "obscura var." from Kungava Bay was based on a darker, shinier 
specimen of vaga. 

18 



Camponotus (Colobopsis) spp. (2) 

Records: Lavanggu (Dan. Exp. L356), a single winged queen; Te-Uhungango (Brit. 
Exp.), three winged queens, several males; Hutuna (Brit. Exp.), 2 winged queens. 
These specimens, representing two species, cannot be determined at present. . 

Camponotus (Myrmamblys) reticulatus Roger 

Records: Lavanggu (Dan. Exp., L374, L390), workers; Te-Maingga (Dan. Exp., 
L362), worker: Te-Avamanggu (Dan. Exp., L364), worker. Collections were made 
in a variety of habitats, including cultivated area with open coconut grove, young se- 
condary forest, and mature rain forest. WHEELER (1934) records reticulatus (= bedoti) 
from KanggavaBay (Lavanggu?), Rennell Island, and from the northwestern corner 
of Bellona Island. 

C. reticulatus occurs from India to Queensland and throughout Melanesia as far 
east as Nupani and Anuda in the Santa Cruz Group. It is especially abundant in 
central and eastern Melanesia, where it occurs even on such remote islands as Sikaiana. 
The terminal populations (India, Queensland, Solomons) can be distinguished from 
each other on the basis of characters in size, sculpturing, and coloration. During the 
present study there was not enough material to determine whether any significant 
differentiation occurs inside Melanesia. Minor workers available in limited series from 
eastern New Guinea, the Solomon Islands and Santa Cruz Islands appear nearly 
identical to each other. 

Polyrhachis (Hedomyrma) annae Mann 

Records: Hutuna (Brit. Exp.), worker; Lavanggu (Dan. Exp., L351, L352, L357, 
L389; E.S. BROWN), workers, dealate queen; Morange (BROWN), worker; Niupani 
(BROWN), worker; Te-Uhungango (BROWN), worker. At Lavanggu the species was 
collected in a cultivated area containing Carica Papaya trees, in coconut groves, and 
in a grove of Pandanus growing on bare coral rock. WHEELER (1934) records the spe- 
cies from Kahggava Bay (at Lavanggu), Rennell I., and the northwestern end of 
Bellona Island. 

P. annae is now known from the following islands in the Solomons and Santa Cruz 
Groups: Bellona, Guadalcanal, Malapaina, Matema, Rennell, San Cristoval, Santa 
Cruz. I have seen two workers of a related, undescribed species from Simba Mission, 
Bougainville, in the collection of the B. P. Bishop Museum. 

Polyrhachis (Myrna) relucens (Latreille) 

Records: Lavanggu (Dan. Exp. L351, L352, L374, L389; E.S. BROWN); Niupani 
(Dan. Exp., L371 ; BROWN) ; Te-Avamanggu (Dan. Exp., L 367); Te-Uhungango (Brit. 
Exp.); Tingoa (Brit. Exp.); Hutuna (Brit. Exp.), male; Morange (BROWN). The spe- 
cies is one of the most widely distributed of Indo-Australian Polyrhachis, ranging con- 
tinuously from New Guinea to northern Queensland and through Melanesia to the 

19 



island of Vanikoro. On Rennell Island it apparently occurs mostly in open situations. 
The Danish Expedition collected it in coconut groves, grassy areas near Lake Te- 
nggano, in cultivated areas, and in small (3-m.-high) secondary forest. 

P. relucens shows marked geographic variation in size, body form (especially spine 
form), pilosity, and coloration. In the present study I have been able to examine series 
from New Guinea, Australia, Solomon Islands, and Santa Cruz Islands. In all charac- 
ters the Rennell samples most closely resemble those from Santa Cruz and Vanikoro, 
and in several characters they depart notably from the Solomons samples (Santa Isa- 
bel, Ugi). This affinity between the Rennell and Santa Cruz populations is unexpected 
in view of the much greater geographic proximity of the Solomons proper to Rennell. 



GENERAL REMARKS ON THE RENNELL FAUNA 

A total of 25 species of ants, representing 17 genera, are now known from Rennell 
Island. The number undoubtedly represents a large percentage, perhaps a majority, 
of the species actually present, but it is almost certainly still incomplete. In evidence 
is the fact that no small ponerines or cryptobiotic myrmicines have yet been collected, 
although judging from the faunas of better-known islands of similar size and isola- 
tion, several species can be expected to occur there. Also, three arboricolous genera, 
Dilobocondyla, Turneria, and Camponotus ( Colobopsis) , are represented in collections 
by a few winged specimens taken at light, leaving the impression that this ecological 
segment of the fauna has only been touched lightly, as also stated by WOLFF (1955 b, 
p. 36). 

Of the 25 species, 4 (in Cerapachys, Dilobocondyla, and Colobopsis) are indeter- 
minate to species. They belong to genera with high degrees of specific endemicity 
(precinctiveness) in Melanesia and hence are very likely native or perhaps even ende- 
mic to Rennell, but their status can be decided only by the examination of more ma- 
terial than is now available. The remaining 21 species have been determined and can 
be analyzed zoogeographically. Of the 21, 3 (Monomorium destructor, Tapinoma me- 
lanocephalum, Anoplolepis longipes) have been introduced into the Solomons by man. 
Ten or eleven of the species (Trachymesopus stigma, Odontomachus simillimus, prob- 
ably O. malignus, Tetramorium pacificum, Vollenhovia oblonga, Pheidole oceanica, P. 
umbonata, Iridomyrmex cordatus, Paratrechina minutula, and Camponotus reticulatus) 
are among the most widespread ant species native to the Indo-Australian Region; 
each ranges from tropical Asia to at least as far as outer Melanesia. Three or four 
species (Cerapachys inconspicuua, Paratrechina vaga, Polyrhachis relucens, probably 
Leptogenysforeli) are limited to Melanesia but widespread from New Guinea at least 
to the Solomons and Santa Cruz Groups. Two species (Tetramorium tonganum, Tur- 
neria dahli) are confined to the islands east of New Guinea, but are still relatively 
widespread, occurring from New Britain to the New Hebrides or beyond. Another 
species (Polyrhachis annae) is known only from the Solomons and Santa Cruz Groups. 
Not a single one of the known Rennell ants is endemic (precinctive) to the island. 

20 



In summary, Rennell appears to be populated chiefly by species that are wide- 
spread elsewhere in the Pacific. Of the twenty species considered to be native to Ren- 
nell, none is peculiar to the island, and only one is limited elsewhere to the Solomons 
andSanta Cruz Islands as a whole. At least seventeen, or 85 %, are in what I have re- 
ferred to elsewhere (1959b) as "Stage-I" in the speciation pattern exhibited generally 
by Pacific ants; that is, they range widely and continuously out of one or the other of 
the three principal faunal source areas Australia, tropical Asia, and New Guinea. 
They are relatively recent invaders of the Solomons and have not yet undergone differ- 
entiation at the species level. The proportion of Stage-I species on Rennell is very high. 
It can be compared with the following percentages of Stage-I species in the subfamily 
Ponerinae for various other parts of Melanesia and Polynesia: New Guinea 22%, 
Bismarck Archipelago 56 %, Solomons 49 %, New Hebrides 82 %, Fiji 18 %, Samoa 
83 %, Society Is. 100 %. 

The Rennell fauna conforms to two rules of Pacific ant geography that have emer- 
ged in recent studies. The first is implied in the data given above, that with all other 
factors being approximately equal, the proportion of Stage-I species increases out- 
ward from the principal faunal source areas. The second is a simple corollary of the 
first: with increasing distance from the source areas the percentage of endemicity de- 
creases. Both trends are reversed on the Fiji Islands and New Caledonia, which are 
old land masses that have been the sites of much local differentiation and radiation 
in ants. Finally, it may be noted that the increase of Stage-I elements at the expense 
of older, Melanesian-endemic elements in isolated islands results in the "oceanic" 
affinities of the Rennell ant fauna, a phenomenon similar to that already observed in 
the Rennell vertebrate fauna by several zoogeographers (Mayr, 1931; Braestrup, 1958; 
Vols0e, 1958). In fact, to call the Rennell fauna "oceanic" is, at least with respect to 
the ants, just another way of saying that the Rennell species are predominantly in 
Stage-I. I have discussed the reasons for this interesting effect in my earlier paper on 
the Melanesian Ponerinae (WILSON, 1959b). The geographic and ecological evidence 
suggest that the Stage-I species are generally endowed with (1) superior dispersal 
powers; and (2) the ability to thrive in "marginal habitats" on the larger islands of 
Melanesia and thus avoid competition with the major part of the older (Stage-II and 
III) fauna, which is concentrated in the more luxuriant parts of the rain forest. 

Isolated islands such as Rennell tend to be populated heavily by Stage-I species 
both because they can be reached only by a minority of groups with adequate dispersal 
facilities and because a relatively large percentage of their area is covered by the mar- 
ginal habitats favored by Stage-I species. These conclusions are in essential agreement 
with the independent opinion of BRAESTRUP (1958) concerning the origin of the verte- 
brate fauna of Rennell Island. 



21 



THE ANTS OF BELLONA ISLAND 

Collections from Bellona are perhaps still too incomplete to allow a critical evaluation 
of the composition of the fauna. Perhaps the most that can be said is that the majority 
of both the native and introduced species have been found on Rennell Island also. 
By far the most distinctive element discovered so far is the monotypic genus Willow- 
siella, described from a single worker from Bellona by WHEELER in 1934. WHEELER has 
placed Willowsiella in the tribe Meranoplini, considering it a distinct, somewhat pri- 
mitive genus perhaps closest to Promeranoplus and Prodicroaspis of New Caledonia. 
If this placement were correct, Willowsiella would hold a strikingly anomalous zoo- 
geographic position, since no other meranopline species are known to occur in the 
main arc of Melanesian islands east of New Guinea. In the opinion of the present 
author, Willowsiella actually belongs in the Tetramoriini. Its entire body form and 
propodeal spine structure seem to place it not far from Triglyphothrix and Romblon- 
ella, two genera strongly developed in the western Pacific. The unusual shapes of the 
petiolar and post petiolar nodes can on close examination be seen to be but a slight 
exaggeration of a morphological trend already apparent in at least one true Triglypho- 
thrix species, T.pacifica Mann. The light body sculpturing and simple pilosity never- 
, theless serve to set off Willowsiella as distinct from the Indo-Australian Triglyphothrix, 
while the lack of an antennal scrobe distinguishes it from Romblonella. Another note- 
worthy Bellona record, established in the present study, is that of an undetermined 
Pheidole (Pheidolacanthinus) , a subgenus hitherto unknown from Rennell. 

Below are listed all of the available records of Bellona ants. These include the 
original records based on the collections of the Templeton Crocker Expedition by 
WHEELER (1934) and the British Museum collections studied by the present author. 
Note that the BRADLEYS' label Matahenua refers to the area between Ahanga, on the 
coast, and the interior village of Matahenua; both localities are at the northwestern 
end of the island. 

Odontomachus simillimus Fr. Smith. Northwestern end of island (Templeton Cro- 
cker Exp.). 

Willowsiella dispar Wheeler. Northwestern end of island (Templeton Crocker 
Exp.). 

Pheidole (P.) oceanica Mayr. Kapata (E. S. BROWN). 

Pheidole (Pheidolacanthinus) sp. A single indeterminate minor worker was col- 
lected by E. S. BROWN. 

Tetramorium pacificum Mayr. Northwestern end of island (Templeton Crocker 
Exp.). 

Tetramorium melanogyna var. pallidiventre Wheeler. Northwestern end of island. 
"Worker. Differing from the typical melanogyna in having the gaster yellow instead 
of fuscous. The mandibles and legs are of the same yellow color as the gaster, the 
knees, however, are infuscated. The petiolar and post petiolar nodes are as coarsely 
reticulate-rugose as the thorax and the marginations are less distinct." No attempt 
has been made to re-evaluate the status of this form, which was based on a single 
worker. 

22 



Iridomyrmex cordatus (Fr. Smith). Matahenua, winged queens, 20.-30.Nov. 1953 
(Brit. Exp.)- A long series of workers were collected on the island by E. S. BROWN in 
1955. 

Anoplolepis longipes (Jerdon). Matahenua, males, 20.-30. Nov. 1953 (Brit. Exp.). 
A series of workers were collected on the island by E. S. BROWN. 

Paratrechlna (Nylanderia) minutula Forel, male, 20.-30. Nov. 1953 (Brit. Exp.); 
no further locality, workers (E.S. BROWN). 

Camponotus (Colobopsis) spp. (2). One of the two species is the same as that re- 
corded from Rennell I. (q.v.). 

Camponotus (Myrmamblys) reticulatus Roger. Northwestern end of island 
(Templeton Crocker Exp.) ; no further locality (E. S. BROWN). 

Polyrhachis (Hedomyrma) annae Mann. Northwestern end of island (Templeton 
Crocker Exp.); no further locality (E.S. BROWN). 

Polyrhachis (Myrma) relucens (Latreille). No further locality (E. S. BROWN). 



REFERENCES 

BRADLEY, J. D., 1955 : 3. Account and list of stations of the British Museum (Natural 
History) Expedition, 1953 - The Natural History of Rennell Island, British Solo- 
mon Islands, 1: 43-57. 

BRAESTRUP, F. W., 1958: 9. The significance of the strong "oceanic" affinities of the 
vertebrate fauna on Rennell Island. - Ibid., 1: 135-148. 

MANN, W. M., 1919: The ants of the British Solomon Islands - Bull. Mus. Comp. 
Zool. Harvard, 63: 273-391. 

- 1948: Ant Hill Odyssey. Little, Brown and Co., Boston. 

VOLS0E, H., 1958 : 8. Herpetology of Rennell Island - The Natural History of Rennell 

Island, British Solomon Islands, 1: 121-134. 
WHEELER, W. M., 1934: Formicidae of the Templeton Crocker Expedition, 1933 - 

Proc. California Acad. Sci., 21: 173-181. 
WILSON, E. O., 1958 : Studies on the ant fauna of Melanesia, I-IV - Bull. Mus. Comp. 

Zool. Harvard, 118: 102-153, 119: 303-371. 

1959: Studies on the ant fauna of Melanesia, V- Bull. Mus. Comp. Zool. Harvard, 

120: 483-510. 

- 1959b: Adaptive shift and dispersal in a tropical ant fauna - Evolution, 13: 122- 
144. 

- 1959c: Some ecological characteristics of ants in New Guinea rain forests - Eco- 
logy, 40: 437-447. 

WOLFF, T., 1955 a: 1. Introduction - The Natural History of Rennell Island, British 
Solomon Islands, 1: 9-31. 

- 1955b: 2. Account and List of Stations of the Danish Rennell Expedition 
Ibid., 1: 33-41. 



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