Aenictus aitkenii

Aenictus aitkenii
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Dorylinae
Genus:	Aenictus
Species:	A. aitkenii
Binomial name
Aenictus aitkenii Forel, 1901 Specimen Labels
Synonyms
Aenictus aratus asiatica Forel, 1911

This species is known from India and Sri Lanka.

Identification

A member of the pachycerus group. This species is similar to A. aratus (with which it has been treated as a junior synonym) and A. nesiotis but differs in having a broader head (cephalic index > 87 versus CI < 88 in A. nesiotis), and broader and more bulbous petiole and postpetiole (both are narrower in A. aratus and A. nesiotis). The scape is also relatively longer than in the others (scape index > 115 versus < 115). It is similar to A. levior in the shape of the head but differs in having longer scapes (Shattuck, 2008).

Keys including this Species

• Key to Aenictus of India

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 32.628611° to 12.54305556°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

Oriental Region: India (type locality), Sri Lanka.

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

Explore Overview of Aenictus biology  Little is known about the biology of Aenictus aitkenii. The genus is comprised of species that live an army ant lifestyle. Aenictus typically prey on other ants, from other genera, or other insects such as wasps or termites. There are reports of Aenictus preying on other insects as well and even have been observed collecting honeydew from homopterans (Santschi, 1933; Gotwald, 1995) but this appears, at least from available evidence, to be uncommon. Foraging raids can occur day or night across the ground surface. Occasionally raids are arboreal. During a raid numerous workers attack a single nest or small area, with several workers coordinating their efforts to carry large prey items back to the nest or bivouac. Aenictus have a nomadic life style, alternating between a migratory phase in which nests are temporary bivouacs in sheltered places above the ground and a stationary phase where semi-permanent underground nests are formed. During the nomadic phase bivouacs move regularly, sometimes more than once a day when larvae require large amounts of food. Individual nests usually contain up to several thousand workers, although nest fragments containing only a few hundred workers are often encountered. Queens are highly specialised and look less like workers than in most ant species. They have greatly enlarged gasters (dichthadiform) and remain flightless throughout their life. New colonies are formed by the division of existing colonies (fission) rather than by individual queens starting colonies on their own. ‎

Castes

Known only from the worker caste.

Nomenclature

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

• aitkenii. Aenictus aitkenii Forel, 1901a: 475 (w.) INDIA (Karnataka, Kerala).
  • Type-material: syntype workers (number not stated).
  • Type-localities: India: Kanara (E.H. Aitken), India: Kanara (R.C. Wroughton), India: Thana (Gleadow), India: Travancore (Ferguson), India: Travancore (Ingleby).
  • Type-depository: MHNG.
  • [Aenictus aitkenii Forel, 1900b: 75 (in text). Nomen nudum.]
  • Junior synonym of aratus: Wilson, 1964a: 446; Bolton, 1995b: 58; Tiwari, 1999: 17.
  • Status as species: Bingham, 1903: 19; Emery, 1910b: 29; Wheeler, W.M. 1919e: 62; Chapman & Capco, 1951: 10; Shattuck, 2008c: 16; Bharti, Wachkoo & Kumar, 2012: 294 (in key); Bharti, Guénard, et al. 2016: 20; Dias, R.K.S. et al. 2020: 22.
  • Senior synonym of asiatica: Shattuck, 2008c: 16.
  • Distribution: India, Sri Lanka.
• asiatica. Aenictus aratus var. asiatica Forel, 1911h: 453 (w.) SRI LANKA.
  • Type-material: syntype workers (number not stated).
  • Type-locality: Sri Lanka (“Ceylon”): (no further data) (E.E. Green).
  • Type-depository: MHNG.
  • Subspecies of aratus: Chapman & Capco, 1951: 10.
  • Junior synonym of aratus: Wilson, 1964a: 446; Bolton, 1995b: 58.
  • Junior synonym of aitkenii: Shattuck, 2008c: 16.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Forel 1901. Page 475.

Type Material

• asiatica. Aenictus aratus var. asiatica Forel, 1911h: 453 (w.) SRI LANKA. Junior synonym of aratus: Wilson, 1964a: 446; of aitkenii: Shattuck, 2008c: 16.

• Aenictus aitkenii: Worker syntypes from Kanara, Thana and Travancore, India.

• Aenictus aratus var. asiatica: Worker syntype from Sri Lanka.

References

• Basu, P. 1997. Seasonal and spatial patterns in ground foraging ants in a rain forest in the Western Ghats, India. Biotropica 29: 489-500.
• Forel, A. 1901a. Les Formicides de l'Empire des Indes et de Ceylan. Part VIII. The Journal of the Bombay Natural History Society. 13:462-477. (page 475, worker described)
• Sahoo, B., Ramakrishnaiah, S., Rajan, P.D., Datta-Roy, A. 2023. A new species of army ant genus Aenictus (Hymenoptera: Formicidae) from India. Journal of the Entomological Research Society 25(3), 615-622 (doi:10.51963/jers.v25i3.2504).
• Shattuck, S.O. 2008c. Review of the ant genus Aenictus in Australia with notes on A. ceylonicus (Mayr). Zootaxa. 1926:1-19.
• Wilson, E. O. 1964a. The true army ants of the Indo-Australian area (Hymenoptera: Formicidae: Dorylinae). Pacific Insects. 6:427-483. (page 446, junior synonym of aratus)

References based on Global Ant Biodiversity Informatics

• Baroni Urbani C. 1977. Katalog der Typen von Formicidae (Hymenoptera) der Sammlung des Naturhistorischen Museums Basel (2. Teil). Mitt. Entomol. Ges. Basel (n.s.) 27: 61-102.
• Basu P. 1994. Ecology of ground foraging ants in a tropical evergreen forest in Western Ghats, India. PhD Thesis, School of ecology and environmental sciences, Pondichery University, India. 155 pages.
• Bharti H., Y. P. Sharma, M. Bharti, and M. Pfeiffer. 2013. Ant species richness, endemicity and functional groups, along an elevational gradient in the Himalayas. Asian Myrmecology 5: 79-101.
• 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
• Chapman, J.W. and S.R. Capco. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monographs of the Institute of Science and Technology (Manila) 1: 1- 327
• Forel A. 1911. Sur le genre Metapone n. g. nouveau groupe des Formicides et sur quelques autres formes nouvelles. Rev. Suisse Zool. 19: 445-459.
• Shattuck, S. O. 2008. Review of the ant genus Aenictus (Hymenoptera: Formicidae) in Australia with notes on A. ceylonicus (Mayr). Zootaxa 1926:1-19.
• Wheeler W. M. 1919. The ants of Borneo. Bulletin of the Museum of Comparative Zoology 63:43-147.