Gesomyrmex chaperi

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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

Gesomyrmex-luzonensisLM4.jpg

Gesomyrmex luzonensis, worker, head.jpg

Specimen Label

Synonyms

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

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Distribution based on AntWeb specimens

Check data from AntWeb

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

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

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.