Technomyrmex albipes group

The following is based on Bolton, 2007.

Species

Notes

This is easily the largest, most diverse and most widespread group of the genus. It contains all the tramp species as well as a number of species with extremely broad natural ranges and its species are mostly the best represented in museum collections. The unique colony reproductive strategy, assumed here to be universal in the group, needs more detailed individual study and a comparative study across the group.

The presence of worker-queen intercastes (Peeters, 1991) and ergatoid males has not been confirmed in all species currently assigned to the group, but they are known for all the common and widespread species as well as some of the rarer ones. Their presence in the remaining species is implied but awaits confirmation. Samples from within nests are essential to detect these intercaste forms as their function is solely reproductive and they do not engage in any activity outside the nest.

To the present, intercaste females have been detected in the following species: Technomyrmex albicoxis, albipes (weak), Technomyrmex antonii, brunneus, Technomyrmex butteli, curiosus, Technomyrmex elatior, difficilis, Technomyrmex fisheri, Technomyrmex furens, Technomyrmex indicus, Technomyrmex innocens, Technomyrmex jocosus, Technomyrmex madecassus, Technomyrmex mayri, Technomyrmex mixtus, Technomyrmex moerens, Technomyrmex nigriventris, Technomyrmex nitens, Technomyrmex pallipes, Technomyrmex quadricolor, Technomyrmex rusticus, Technomyrmex vapidus, sophiae and Technomyrmex vitiensis.

Apterous (ergatoid) males have been detected in albipes, brunneus, difficilis, jocosus, moerens and pallipes.

Description

Worker. Palp formula 6,4. Anterior clypeal margin with a shallow median impression or a small notch (Technomyrmex modiglianii complex). Frontal carinae with setae present, usually -3 along each carina. Pronotum usually with at least one pair of setae (only very rarely absent). Propodeal dorsum without setae. Gastral tergites 1 - 4 with setae present, usually numerous and conspicuous (absent only in Technomyrmex curiosus). Mesosoma relatively short and compact, the mesonotum never with a constricted or elongated appearance in dorsal view or in profile. Predominant sculpture everywhere on head and body finely, densely microreticulate or reticulate-shagreenate, only rarely glassy smooth (Technomyrmex sophiae complex). Ergatoid morphological intercastes are present between true workers and true (alate) queens. Apterous (ergatoid) as well as alate males are produced. Colony reproductive strategy of this group is apparently unique in Formicidae (see outlines under Technomyrmex brunneus and Technomyrmex difficilis.

Complexes

A number of complexes of related species can be isolated within the group. The Afrotropical species Technomyrmex rusticus is known only from a worker-queen intercaste and does not fit any complex given below.

T. albipes complex

Technomyrmex albipes, Technomyrmex brunneus, Technomyrmex butteli, Technomyrmex curiosus, Technomyrmex hades, Technomyrmex moerens, Technomyrmex nigriventris, Technomyrmex pluto, Technomyrmex vitiensis

Setae on the dorsum of the head are restricted to the frontal carinae, none occurs posterior to this. Propodeum in profile is acutely to bluntly angular between dorsum and declivity; dorsum is short. Extremely widespread. This complex contains two of the most successful tramp species, albipes and vitiensis.

T. cedarensis complex

Technomyrmex antonii, Technomyrmex australops, Technomyrmex cedarensis

Dorsum of head with a single pair of setae behind the level of the eyes, the latter large and located relatively posteriorly on the head capsule. Propodeal dorsum short and meeting the declivity in an angle. Restricted to Queensland and New South Wales in Australia.

T. cheesmanae complex

Technomyrmex albicoxis, Technomyrmex cheesmanae, Technomyrmex mixtus, Technomyrmex prevaricus, Technomyrmex tonsuratus

Five species from New Guinea, with cheesmanae also occurring in Queensland, in which the propodeum in profile is rounded rather than angular.

T. modiglianii complex

Technomyrmex elatior, Technomyrmex modiglianii, Technomyrmex yamanei

The anterior clypeal margin has a relatively conspicuous median notch that is deeper and more obvious than in any other complex of the group) where the margin has at most a shallow indentation medially. The posterior margin is broadly emarginate across its width in full-face view. Widespread in the Oriental and Malesian regions.

T. pallipes complex

Technomyrmex certus, Technomyrmex difficilis, Technomyrmex fisheri, Technomyrmex fornax, Technomyrmex indicus, Technomyrmex innocens, Technomyrmex jocosus, Technomyrmex madecassus, Technomyrmex mayri, Technomyrmex myops, Technomyrmex pallipes, Technomyrmex rotundiceps, Technomyrmex setosus, Technomyrmex subgracilis, Technomyrmex vapidus

Setae on dorsum of head not restricted to frontal carinae, at least one pair present posterior to level of eyes and often more. Eyes smaller and located more anteriorly than in the preceding group. Propodeal dorsum short; junction of dorsum and declivity angulate to bluntly rounded. This complex is grounded for convenience, the residue that remains after other species have been accounted for.

T. semiruber complex

Technomyrmex hostilis, Technomyrmex menozzii, Technomyrmex semiruber

Afrotropical species in which the propodeal dorsum rounds broadly and evenly into the declivity; the true dorsum is very short and forms the anterior part of a broad curve that extends to the propodeal spiracle.

T. sophiae complex

Technomyrmex furens, Technomyrmex nitens, Technomyrmex quadricolor, Technomyrmex sophiae

Characterised within the group by the loss of the usual shagreenate/microreticulate sculpture, especially on the head, pronotum and first gastral tergite, leaving at least the head glassy smooth. The propodeum is bluntly but quite narrowly rounded and on the dorsum of the head setae are not restricted to the frontal carinae. Restricted to Queensland, Australia. Because of the lack of sculpture these species resemble the Technomyrmex strenuus group, but members of that group always have setae present on the propodeal dorsum.

Related Pages

References

Bolton, B. 2007b. Taxonomy of the dolichoderine ant genus Technomyrmex Mayr (Hymenoptera: Formicidae) based on the worker caste. Contributions of the American Entomological Institute. 35(1):1-149.