Technomyrmex vitiensis

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Technomyrmex vitiensis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dolichoderinae
Genus: Technomyrmex
Species: T. vitiensis
Binomial name
Technomyrmex vitiensis
Mann, 1921

Technomyrmex vitiensis casent0005326 profile 1.jpg

Technomyrmex vitiensis casent0005326 dorsal 1.jpg

Specimen Label

Synonyms

T. vitiensis is an accomplished tramp species although collections are not as numerous as they are for albipes. It nests in a wide variety of locations and has been collected from leaf litter, under stones, in rotten wood and from vegetation where it may nest in twigs, rot holes and spathes. Foraging is carried out in all of these places and the species, as well as avidly tending homopterous insects for honeydew, will also kill and consume small arthropods (Bolton, 2007).

At a Glance • Wingless male  
 

Identification

Bolton (2007) - A member of the T. albipes complex in the Technomyrmex albipes group. T. vitiensis workers are separated from albipes by the following characters. In vitiensis the mesonotum is angled as described above, the pronotum usually has 1 pair of setae, the mesonotum lacks setae and the propodeal dorsum and declivity meet in a distinct angle in profile. The scape in vitiensis is both absolutely and relatively longer (SL 0.58 - 0.64, SI 104 - 115), the eyes are larger (OI 29 - 32) and the promesonotum is longer (DTI 128 - 141). In albipes workers the mesonotum is evenly curved, the pronotum usually has 2 pairs of setae and the mesonotum none, although some individuals with only 1 pronotal pair and some with a pair of mesonotal setae are known; the propodeal dorsum an declivity meet in a short, narrowly rounded blunt curve in profile. The scape in albipes is both absolutely and relatively shorter (SL 0.48 - 0.58, SI 93 - 102), and the eyes are smaller (OI 24 - 27), the difference in eye size appears obvious when workers of the two species are directly compared; the promesonotum of albipes is shorter (DTI 110 - 124).

Also see Pacific Invasive Ant key for identification.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Comoros, Kenya.
Australasian Region: New Caledonia.
Indo-Australian Region: Borneo, Fiji (type locality), French Polynesia, Indonesia, Malaysia, New Guinea, Niue, Philippines, Samoa, Solomon Islands, Vanuatu.
Malagasy Region: Mayotte, Seychelles.
Nearctic Region: United States.
Neotropical Region: French Guiana.
Oriental Region: Bangladesh, India, Myanmar, Thailand.
Palaearctic Region: Belgium.
Technomyrmex vitiensis Distribution.png

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Biology

Castes

Bolton (2007) - Morphological worker-queen intercastes are common in this species but it is not known if they occur outside of nests. The intercastes between worker and queen form a sequence in which ocelli gradually appear (first the median then the two laterals) and the mesosoma gradually acquires a more queen-like appearance and arrangement of sclerites, but without ever developing wings. The mesonotum becomes extended posteriorly and begins to overhang the metanotal groove. The mesonotum increases somewhat in size and becomes subdivided into a mesoscutum and smaller mesoscutellum, poorly differentiated at first but gradually becoming more obviously discrete sclerites. A pair of setae may appear on the mesoscutellum. The entire mesosoma begins to appear more swollen and the mesoscutellum begins to be separated from the pleuron, initially by a faint line then by a distinct impression. At the base of the metanotal groove a separate metanotum becomes distinguished, increasing gradually in size until it forms a small, separate, dorsally-projecting sclerite. Preliminary dissections indicate that spermathecae are present in intercastes.

Peck & Bezdek (2016) - Wingless males are known to occur in this species.

Worker

Queen

Male

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • vitiensis. Technomyrmex albipes var. vitiensis Mann, 1921: 473 (w.) FIJI IS. Santschi, 1928a: 52 (m.). Junior synonym of albipes: Wilson & Taylor, 1967: 82. Revived from synonymy, raised to species and senior synonym of rufescens: Bolton, 2007a: 104.
  • rufescens. Technomyrmex albipes st. rufescens Santschi, 1928c: 70, fig. 1 (w.) FIJI IS. Junior synonym of albipes: Wilson & Taylor, 1967: 82; of vitiensis: Bolton, 2007a: 104.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Bolton (2007) - TL 2.4 - 3.1, HL 0.59 - 0.66, HW 0.52 - 0.60, SL 0.58 - 0.64, PW 0.35 - 0.44, WL 0.76 - 0.92 (25 measured). Indices: CI 85 - 93, SI 104 - 115, OI 29 - 32, EPI 64 - 84, DTI 128 - 141.

Frontal carina with 2 (very rarely 3) setae. Dorsum of head posterior to this entirely lacks setae. With head in full-face view the anterior c1ypeal margin with a very weak, shallow median indentation; sides of head shallowly convex and the posterior margin with a small shallow indentation medially. Eyes located in front of midlength, EPI above. With mesosoma in profile the mesonotal dorsal outline is usually distinctly stepped, with an obtuse angle in the outline that separates a relatively long, shallowly convex to approximately flat, anterior section from a shorter, much more steeply descending declivitous face. Number of setal pairs on mesosoma: pronotum 1, somewhat shorter than maximum diameter of eye (uncommonly a second shorter pair also present in weak intercaste forms); mesonotum 0 (in some worker-queen intercastes a short pair may occur on the emergent mesoscutellum); propodeal dorsum 0; lateral margin of propodeal declivity 1. With the propodeum in profile its dorsum and declivity meet in a distinct angle, not a short rounded curve. Gastral tergites 1 - 4 each with numerous setae, distributed everywhere on the sclerites; maximum length of setae on first gastral tergite less than the maximum diameter of the eye. Head, mesosoma, petiole and gaster usually uniformly medium to dark brown, but black in some populations; in some the gaster may be slightly darker than the mesosoma. Coxae, femora and tibiae of middle and hind legs sometimes all the same colour, usually about the same colour as the mesosoma or slightly lighter, but often the middle and hind coxae are slightly to much lighter than the mesosoma. Tarsi of middle and hind legs yellow, paler than the femora and usually also the tibiae, but in some the tibiae are paler than the femora and approach the colour of the tarsi.

Type Material

Bolton (2007) - Syntype workers, Fiji Is: Viti Levu, Nadarivalu (W. M. Mann) (National Museum of Natural History, Museum of Comparative Zoology) [examined].

Only workers are mentioned in the original description but the series also contains a number of queens. One queen, on a pin with two T. vitiensis workers (USNM), is a formicine and has obviously been mounted with them by accident; all workers are T. vitiensis. Many specimens from Fiji Is in MCZC are labeled as "types" but come fromlocalities noted by Mann (1921) other than the type-locality.

Determination Clarifications

Wilson & Taylor (1967) included the two then-infraspecific names vitiensis and Technomyrmex rufescens as junior synonyms of Technomyrmex albipes, and listed an enormous amount of material from throughout Polynesia. T. vitiensis (with rufescens now established as a junior synonym) has proved to be a species separate from albipes, so a re-appraisal of the Wilson & Taylor material will be necessary to show the respective distributions of the two through the island systems. It is expected that specimens of a third tramp species, Technomyrmex difficilis, will also be present.

References