Species: Tetraponera (grandidieri) inermis

Taxonomic History (provided by Barry Bolton, 2013)

Distribution:

T. inermis occurs in eastern Madagascar from Montagne d'Anjanaharibe to the vicinity of Tolagnaro (Fort Dauphin). Collections all come from rainforest, at elevations ranging from 30 m to 1040 m.

Biology:

T. inermis is apparently confined to rainforest. Nests are located in rotten sticks on the ground, and are small in size. At the type locality (1 km SSW Andasibe) a dealate queen was observed gleaning the surfaces of leaves, walking rapidly and raising her gaster in the air; she then returned to her nest--a cavity in a small soft dead twig on the ground--which proved to contain eggs, larvae and worker pupae  (Ward, 2009). Thus, this species exhibits non-claustral colony-founding, a trait presumably shared with  other members of the T. grandidieri group. The gaster-raising behavior was observed in foraging  workers of T. inermis but not those of the other two species with which T. inermis is sympatric: T.  grandidieri and T. merita. Camponotus reaumuri Forel (related to C. putatus Forel) is a possible mimic  of T. inermis.

Identification:

Within the grandidieri group this species is recognized by a combination of the following worker features:

• basal margin of mandible lacking tooth; masticatory margin with four teeth
• petiole slender, obovate, with an elongate anterior peduncle
• metanotal spiracle not protruding above the profile of the mesosoma, as seen in lateral view
• head broad (CI 0.88-0.97)
• head and mesosoma reddish-brown, metasoma and appendages paler

Taxonomic Notes:

The worker of T. inermis can be recognized by the absence of a tooth on the basal margin of the mandible; the more or less concolorous reddish-brown body (the upper half of propodeum is often a richer dark red, and the metasoma is paler); and the lack of a protruding metanotal spiracle when the  mesosoma is viewed in profile. In addition, the head tends to be broader than that of T. grandidieri and T. hespera (CI 0.88-0.97, versus 0.77-0.88 in T. grandidieri and 0.78-0.90 in T. hespera). From T. hespera it can also be distinguished by the ratio of metatibial length to head width (LHT/HW 1.02-1.09 in T. inermis, and 1.10-1.22 in T. hespera).

References:

Ward, P. S. 2009. The ant genus Tetraponera in the Afrotropical region: the T. grandidieri group (Hymenoptera: Formicidae). Journal of Hymenoptera Research 18: 285-304.

Taxon Page Author History

Specimen Data Summary

Found most commonly in these habitats: 26 times found in rainforest, 2 times found in rainforest, transition to montane forest

Collected most commonly using these methods or in the following microhabitats: 4 times MW 50 sample transect, 5m, 2 times beating low vegetation, 2 times 9 Maxi winklers, 1 times Malaise trap, 1 times pitfall trap, PF 50 sample transect, 5m

Elevations: collected from 30 - 920 meters, 473 meters average

1 Specimens Imaged | View All 34 Specimens for this species

CASENT0012862

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