Gesomyrmex chaperi

Gesomyrmex chaperi
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Formicinae
Tribe:	Gesomyrmecini
Genus:	Gesomyrmex
Species:	G. chaperi
Binomial name
	Gesomyrmex chaperi; André, 1892 Specimen Label
Synonyms
	Dimorphomyrmex janeti André, 1892;

Peeters et al. (2017) studied ten complete nests from three populations (northern Thailand, peninsular Malaysia and Sabah) of Gesomyrmex, and they may all correspond to G. chaperi.

Identification

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo (type locality), Indonesia, Malaysia.
Oriental Region: Cambodia.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

See Gesomyrmex

Observations of behaviour are challenging in tree canopies, and Peeters et al. (2017) used functional morphology to predict the specialised functions of different castes. Disproportionately large eyes and piercing mandibles are consistent with workers being agile hunters. Soldiers and supersoldiers share robust mandibles, but the latter have a rectangular head and substantially larger body size, like the queens. This suggests both supersoldiers and queens have the muscular power necessary to chew entrance tunnels in healthy wood. Queens and supersoldiers also share frontal lobes (protection for antennal bases), suggesting that they block nest entrances with their heads. When founding a nest, newly mated queens need to chew an entrance tunnel that reaches the innermost soft pith. Supersoldiers are mostly restricted inside nests where they store nutrients in their gaster, but they may also chew the entrance tunnels of additional nests as the colony expands.

All castes and brood huddled together in the nest. To access the secure innermost pith, the founding queen needs to chew an entrance tunnel. Atypically for subfamily Formicinae, the pupae lack a cocoon. Photo by Christopher Wilson

Workers have nimble piercing mandibles and bulging eyes that allow overlapping fields of view (i.e. 3D and lateral vision). This is consistent with hunting live prey in the canopy. SEM by Christian Peeters

Differences in body size among worker, soldier and supersoldier. Photo by Christian Peeters

Castes

SEM of heads of the various castes. SEM by Christian Peeters

Images from AntWeb


Worker. Specimen code casent0102086. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by MSNG, Genoa, Italy.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

chaperi. Gesomyrmex chaperi André, 1892b: 47, fig. 1-3 (w.) BORNEO. Senior synonym of janeti: Wheeler, W.M. 1929a: 10.
janeti. Dimorphomyrmex janeti André, 1892b: 51, figs. 4, 5 (s.w.) BORNEO. Junior synonym of chaperi: Wheeler, W.M. 1929a: 10.

Description

References

André, E. 1892c. Voyage de M. Chaper à Bornéo. Catalogue des fourmis et description des espèces nouvelles. Mém. Soc. Zool. Fr. 5: 46-55.
Aria, C., Jouault, C., Perrichot, V., Nel, A. 2023. The megathermal ant genus Gesomyrmex (Formicidae: Formicinae), palaeoindicator of wide latitudinal biome homogeneity during the PETM. Geological Magazine, 1–11 (doi:10.1017/s0016756822001248).
Peeters C, Ito F, Wiwatwitaya D, Keller R, Hashim R & Molet M. 2017. Striking polymorphism among infertile helpers in the arboreal ant Gesomyrmex. Asian Myrmecology 9: e009015 (1-15) PDF
Wheeler, W. M. 1929a. The identity of the ant genera Gesomyrmex Mayr and Dimorphomyrmex Ernest André. Psyche (Camb.) 36: 1-12 (page 10, Senior synonym of janeti)
Yamane, S., Tanaka, H.O., Hasimoto, Y., Ohashi, M., Meleng, P., Itioka, T. 2021. A list of ants from Lambir Hills National Park and its vicinity, with their biological information: Part II. Subfamilies Leptanillinae, Proceratiinae, Amblyoponinae, Ponerinae, Dorylinae, Dolichoderinae, Ectatomminae and Formicinae. Contributions from the Biological Laboratory, Kyoto University 31, 87–157.

References based on Global Ant Biodiversity Informatics

André E. 1892. Voyage de M. Chaper à Bornéo. Catalogue des fourmis et description des espèces nouvelles. Mém. Soc. Zool. Fr. 5: 46-55.
Chapman, J. W., and Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327
Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58
Wheeler W. M. 1916. Four new and interesting ants from the mountains of Borneo and Luzon. Proceedings of the New England Zoological Club 6: 9-18.
Wheeler W. M. 1929. The identity of the ant genera Gesomyrmex Mayr and Dimorphomyrmex Ernest André. Psyche (Cambridge) 36: 1-12.