Camponotus irritabilis

This species and its New World congener Camponotus femoratus have a reputation as some of the world's most aggressive ant species. Their mandibles can readily break the skin of an unwary or unlucky myrmecologist, and the ants add to this discomfort by spraying the cut with formic acid. An individual doing this is annoying. These ants though attack en mass and can deliver many such bites at once.

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

Biology
Weissflog et al (2017) - Camponotus irritabilis and Hoya elliptica (Apocynaceae) are very closely associated in ant gardens in Malaya and Sumatra. Ants and epiphyte partners have some characteristics that make them especially suitable for this association: The ants selectively retrieve the seeds of their epiphyte partners, and they fertilize their carton nests on which the plants are growing. In comparison to non-myrmecophytic Hoya coriacea, Hoya elliptica performs an extensive root growth as long as growing on moist substrate. The roots stabilize the ants’ nests and anchor them to the host tree. Camponotus irritabilis initiate ant gardens by constructing carton buildings on branches, which serve as substrate for incorporated seeds and climbing parts of already established Hoya elliptica. Camponotus irritabilis influence actively the available chamber size within their nests, by biting off roots, fertilizing only certain parts of the nests and retrieving seeds into the ‘growing zone’ of the nest building. Ants thereby prevent uninhibited, space-consuming root growth but influence stability and architecture of the ant garden by guiding the spread out of the roots. As additional partners of the ant garden system, trophobionts, undetermined fungi on the inner nest substrate, several parabiotic Crematogaster spp. and a probably lestobiotic Solenopsis sp. were found. Similarity in genus composition of the three co-occurring ants, as well as behaviors of Camponotus irritabilis, degree of the mutual benefits with the epiphytes and phenology of this ant garden association might represent a remarkable case of convergence with neotropical ant gardens.

Nomenclature

 *  irritabilis. Formica irritabilis Smith, F. 1857a: 56 (w.) BORNEO. Combination in Camponotus: Roger, 1863b: 3; in C. (Myrmotarsus): Forel, 1912i: 92. Current subspecies: nominal plus winkleri.

Formica irritabilis

Holotype worker in. Labelled “SAR 7.”