Purchased by U. S. Department of
WH F M , AgricuJ.tv.- for official use
WILLIAM L. BROWN
Eeprinted from JOURNAL or THE NEW YOEK ENTOMOLOGICAL SOCIETY,
Vol. LXV, September, December, 1957, pages 195-198.
A CONTRIBUTION TO THE TAXONOMY,
DISTRIBUTION AND BIOLOGY OF THE
VAGRANT ANT, PLAGIOLEPIS ALLUAUDI EMERY
(HYMENOPTERA, FORMICIDAE)
BY MARION E. SMITH
ENTOMOLOGY BESEARCH BRANCH
AGRICULTURAL RESEARCH SEEVICE
UNITED STATES DEPARTMENT OP AGRICULTURE, WASHINGTON, D. C.
About 1946 a small, yellow Plagiolepis was intercepted by
Plant Quarantine Inspectors of the U. S. Department of Agri-
culture on such plants as gladiolus, croton, poinsettia, daisy, hibis-
cus, bryophyllum, pampas grass and Surinam cherry from the
Bermuda Islands. At that time only a generic identification was
made, although it was recognized that the ant was an introduc-
tion from the Old "World. Plagiolepis is native only to the Old
World. Furthermore, although species of Plagiolepis have been
spread by commerce over various parts of the world, so far as I
am aware none has been correctly reported from the New World.
Plagiolepis flavidula Eoger (1863, Berlin Ent. Ztschr. 7:162,
worker, type locality unknown but thought to have been Cuba)
is definitely a species of Brachymyrmex, according to H. Bischoff,
who recently examined the type. These circumstances led me to
investigate thoroughly the intercepted P-lagiolepis in order to de-
termine its status, distribution, and recorded biology. I thought
the ant might be alluaudi Emery, a species originally described
from the Seychelles, or a closely related form. The type speci-
men of alluaudi was borrowed from the Museo Civico di Storia
Naturale of Genoa, and the type of foreli Santschi from the
Naturhistorisches Museum of Basel. Types of augusti Emery
(foreli Mann not Santschi) .are in the National Museum at Wash-
ington, D. C. Examination of the types of these three nominal
species showed them to represent a single species, identical with
the intercepted Plagiolepis, to which the name alluaudi should
be applied. I am indebted to W. L. Brown for ascertaining that
the type of mactavishi W. M. Wheeler, in the Museum of Com-
parative Zoology, Cambridge, Mass., is so nearly identical with
alluaudi that the name mactavishi should be and is herewith
ft
196 NEW YORK ENTOMOLOGICAL SOCIETY [VOL. LXV
synonymized. I was not able to obtain types of ornate Santschi,
but am synonymizing that species on the basis of the description
alone.
For the kindness of loaning me types of the various nominal
species I wish to thank the following: Delfa Guiglia of Genoa,
Ed. Handschein of Basel, and Charles Ferriere of Geneva.
Below are listed references to alluaudi and its synonyms, with
an indication of caste or castes from which described, type local-
ity and type repository. Also cited are other helpful biblio-
graphic references.
Plagiolepis alluaudi Emery
Plagiolepis alluaudi Emery, 1894. Soc. Ent. de France Ann.
63: 71, worker. (La Misere, Mahe, Seychelles; types in
Museo Civico di Storia Naturale, Genoa, Italy.)
Plagiolepis mactavishi W. M. Wheeler, 1908. Amer. Mus. Nat.
Hist. Bui. 24: 166, ivorker. (Moorea, Tahiti, Society Is-
lands ; types in Museum of Comparative Zoology, Cambridge,
Massachusetts.) New syn.
Plagiolepis foreli Santschi, 1920. Soc. Vaud. des Sci. Nat. Bui.
53 : 165, figs. G. H. I, worker. (Botanical Garden, Zurich,
Switzerland; types in Naturhistorisches Museum, Basel,
Switzerland.) Emery, 1921. Soc. Ent. de Belg. Ann. 61:
318 (as alluaudi var. foreli.) New syn.
Plagiolepis foreli var. ornata Santschi, 1920. Soc. Vaud. des
Sci. Nat. Bui. 53: 166, worker. (New Caledonia; types in
Naturhistorisches Museum, Basel, Switzerland.) Emery,
1914. Nova Caledonia Zool. 1 : 421 (misdet. as exigua var.
quadrimaculata Forel.) Emery, 1921. Soc. Ent. de Belg.
Ann. 61: 318 (as alluaudi var. ornata). New syn.
Plagiolepis foreli Mann, 1921. Harvard Univ., Mus. Compar.
Zool. Bui. 64: 473, worker. (Suava, Viti Levu, Fiji Is-
lands; types in the United States National Museum, Wash-
ington, D. C.) Preocc. New syn.
Plagiolepis augusti Emery, 1921. Soc. Ent. de Belg. Ann. 61 :
317. New name for foreli Mann. New syn.
I offer here a redescription of the worker only, with emphasis
on the more salient characters.
WOKKER. Length: 1.25-1.33 mm.
Apex of scape very distinctly surpassing the posterior border of the head
Sept.-Dec., 1957] SMITH: ANTS 197
(by at least the length of the first funicular segment) ; the second and third
funicular segments extremely short, and distinctly broader than long; all
other funicular segments longer than broad. Eye with 8 to 10 ommatidia
in its greatest diameter. Thorax with a very distinct mesoepinotal constric-
tion but the metanotal suture obsolescent. Clypeus with a-group of approxi-
mately 6 rather long, anteriorly projecting hairs. A pair of short, suberect
or erect hairs near the middle of the posterior border of the head (these not
clearly seen unless the hairs are in profile; one or both of the hairs are
sometimes missing, probably due to rubbing). Posterior border of each
gastric segment with a transverse row of long, suberect to erect hairs dor-
sally, the hairs usually- as long as, or longer than the space separating adja-
cent hairs. Pubescence on body rather sparse, closely appressed, best seen
only in certain lights and positions. Color highly variable even in indi-
viduals from the same colony, ranging from an almost uniform light yel-
lowish to rather dark brown ; gaster commonly darker .than the remainder of
the body. Integument or body rather smooth and shining.
Evidence obtained from literature indicates that alluaudi is
of Ethiopian origin and has been spread by commerce to various
parts of the world. In Europe it has been found in hot houses
or botanical gardens in England, Scotland, Ireland, Germany,
and Switzerland. It has also been collected from many islands
in the Indian and Pacific Oceans, especially those nearest Africa
and Madagascar. Its presence on islands in the Pacific Ocean is
presumably due to introduction. In addition to the Bermuda
Islands, I have seen individuals from Catalina Island, California,
collected by W. M. Mann, and from St. Lucia and St. Kitts in
the British West Indies intercepted on plants by Plant Quaran-
tine Inspectors of the U. S. Department of Agriculture. So far
as I am aware, records from these four localities have not been
previously published. More specific information on the distri-
bution of alluaudi may be obtained in the following references :
(as alluaudi} W. M. Wheeler, 1922, Amer. Mus. Nat. Hist. Bui.
45: 928, 1035; Donisthorpe, 1927, British Ants, p. 396, Geo.
Routledge and Sons Ltd., London; (as mactavishi) W. M.
Wheeler, 193-5, Bernice P. Bishop Mus., Occas. Papers 11 (11) :
38, and 1936, op cit., 12 (18) : 16 ; (as ornata and augusti) W. M.
Wheeler, 1935, op. cit.
The following notes' on the habits of alluaudi in Bermuda have
been kindly supplied by I. W. Hughes. It is fairly definite that
the species has been in Bermuda for at least 5 or 6 years, and
although widely distributed it does not seem to be numerous any-
where. The species frequently nests under the bark of dead
oleander limbs or in tunnels in this or other plants made by the
]98 NEW YORK ENTOMOLOGICAL SOCIETY [VOL. LXV
cerambycid Leptostylus praemorsus (F.). Some colonies are
rather large and they may even be polydomus. The large size
of many colonies can no doubt be attributed to the numerous egg-
laying females. The largest colony observed was in a clump of
oleander heavily infested with Pulvinaria psidii Maskell and
containing much dead wood. The workers are rather inconspicu-
ous on the plants and do not seem inclined to wander far from
their nests. They apparently live on good terms with other ants,
especially with Pheidole megacephala (F.). The workers are
primarily sweet-eating and accustomed to tending honeydew-ex-
creting insects, such as the green shield scale, Coccus viridis
Green, Pulvinaria psidii and a species of the genus Saissetia.
P. alluaudi is a household pest of some importance, commonly
invading houses at night and seeking out sweets and fats. How-
ever, it is not as common or economically important in Bermuda
as Iridomyrmex humilis Mayr and Pheidole megacephala (F.).
P. alluaudi may be the only species in Hawaii, although it has
been recorded from there as both mactavishi W. M. "Wheeler and
exigua Forel. Philipps (1934. Univ. Hawaii Bxpt. Sta. of
Pineapple Producers Coop. Assn. Ltd., Bui. 15 : 54) states that
the species is widely distributed there. He attributes its success
to a short life cycle, tolerance of limits of temperature and hu-
midity, and an ability to live in harmony with other ants, espe-
cially the more aggressive ones. In Hawaii as in Bermuda,
workers commonly tend honeydew-excreting insects, but their im-
portance in fostering or distributing these insects, particularly
the pineapple mealybug, is not so clearly established as is that of
some of the other ants. The ants are said to nest in houses, al-
garoba hollows, and pineapple stumps, and under stones and
mulch. Ehrhorn (1931. Proc. Haw. Ent. Soc. 7: 393) found
alluaudi in houses, especially after rains. He stated that this
species and Pheidole megacephala entered electric conduits and
destroyed the insulation. Krauss in a letter referred to alluaudi
as a house-infesting ant in Hawaii with a fondness for sweets.
Plagiolepis alluaudi is admirably adapted for becoming widely
distributed by commerce throughout the tropical and semitropi-
cal parts of the world. It would not be surprising to learn of its
presence in many more localities than are now known. The fact
that it is a tramp species also accounts for many of the synonyms.
