Odontomachus opaciventris

In Monteverde the diurnal foragers are common, and on warm days alate queens commonly fly into buildings. Nests are in rotten wood on the ground. Workers have been observed harvesting Calathea seeds. The species is rare at La Selva. (Longino, Ants of Costa Rica)

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Colombia, Costa Rica, Ecuador, Guatemala, Honduras, Mexico, Panama.

Biology
Colony sizes recorded as 5000, 8000, and 10000 workers, with one queen (De la Mora et al. 2008). Nest chambers spread throughout fallen logs as well as in superficial soil underneath.

In order to study both the hunting efﬁciency and the ﬂexibility of their predatory behavior, solitary hunters of the trap-jaw ant Odontomachus opaciventris  were offered small prey (termites, fruit ﬂies and tenebrionid larvae), presenting different morphological or defensive characteristics.The monomorphic hunters showed a moderately ﬂexible predatory behavior characterized by short capture sequences and a noteworthy efﬁciencyof their mandible strike (76.7–100% of prey retrievals), even when presented with  Nasutitermes  soldiers. Contrary to most poneromorph ants,antennal palpation of the prey before the attack was always missing,noparticular targeted region of the prey’s body was preferred,and no‘prudent’posture was ever exhibited. Moreover, stinging was regularly performed on bulky, fast moving fruit ﬂies, very scarcely with sclerotized tenebrionid larvae, but never occurred with Nasutitermes workers or soldiers despite their noxious chemical defense. These results suggest that, whatever the risk linked to potentially dangerous prey, O. opaciventris  predatory strategy optimizes venom use giving top priority to the swiftness and strength of the lethal trap-jaw system used by hunters as ﬁrst strike weapon to subdue rapidly a variety of small prey, ranging from 0.3 to 2 times their own body size and from 0.1 to 2 times their weight. Such risk-prone predatory behavior is likely to be related to the large size of O. opaciventris colonies where the death of a forager might be of lesser vital outcome than in small colony-size species

Nomenclature

 *  opaciventris. Odontomachus haematodus r. opaciventris Forel, 1899c: 21, pl. 1, fig. 14 (w.q.) MEXICO. Raised to species: Kempf, 1972a: 172; Brown, 1976a: 105.