Colobopsis badia

A canopy nesting species that is a member of the Colobopsis cylindrica group, a set of species that employ a novel defensive strategy. Minor workers of these so called exploding ants will, when threatened, flex their gasters so hard that they rupture. This releases a toxic chemical mixture that they then attempt to smear on their antagonists.

Identification
The male of Colobopsis badia can be distinguished from males of Colobopsis explodens by larger body size, differing colour pattern, more shiny integument, well-developed clypeal carina, differing proportions of wing venation, and relatively shorter scapes. In the genitalia, the most striking differences are in the narrower gonostylus and the more rounded digitus apex.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Malaysia, Singapore. Oriental Region: India.

Biology
Zettel et al. (2018) examined foraging ecology of this species and Colobopsis leonardi. Workers of a C. badia colony were observed on leaves of low vegetation and on lianas leading up to two small trees (Figure 2). Nest entrances were not found; they were most probably located higher up in the tree, as is often the case in COCY colonies. Feeding experiments were carried out on June 6, at around 10:30 a.m. when a moderately high activity of workers (higher than on the previous and following days) was observed on an ant trail on a ca. 2 cm thick liana ca. 0.5 m above ground. As a preliminary feeding experiment, three freshly killed specimens of Coptotermes curvignathus termites were placed on the liana at a distance of ca. 5 cm from each other. Workers approaching this area shrunk back without touching the C. curvignathus specimens and/or alarmed nest mates with highly raised gasters. The area was subsequently avoided by most (not all) workers which then used a liana running parallel to the first one. During the time of observation, a C. badia worker was observed carrying a small item. Worker and item were caught and preserved. The item was a very small male ant (presumably Dolichoderinae).

Nomenclature

 *  badia. Formica badia Smith, F. 1857a: 54 (w.) SINGAPORE. Viehmeyer, 1916a: 161 (m.). Combination in Camponotus: Roger, 1863b: 3; in C. (Colobopsis): Forel, 1913k: 133. [Unresolved junior primary homonym of Formica badia Latreille, 1802c: 238 (now in Pogonomyrmex (Bolton, 1995b: 87).] Current subspecies: nominal plus saginatus. Combiniation in Colobopsis: Ward, et al., 2016: 350.

Formica badia

Three worker syntypes in. One labelled “Sing. 6,” two labelled “Sar. 32.” Smith records both localities in the original description. There is also a single worker from Sumatra, det. as badia by Smith.