Aenictus nishimurai

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Aenictus nishimurai
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Aenictus
Species: A. nishimurai
Binomial name
Aenictus nishimurai
Terayama & Kubota, 1993

Aenictus nishimurai side (www.niaes.affrc.go.jp).jpg

Aenictus nishimurai top (www.niaes.affrc.go.jp).jpg

Specimen labels

No biological information is available for Aenictus nishimurai. However, judging from the localities cited above this species is distributed from lowland to highland (200-1,500 m) and inhabits primary, secondary and disturbed forests. (Jaitrong & Yamane 2012)

Identification

A member of the javanus species group. This species is most similar to Aenictus doydeei (see under that species).

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Oriental Region: Laos, Thailand (type locality), Vietnam.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Little is known about the biology of Aenictus nishimurai. 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 New General Catalogue, a catalogue of the world's ants.

  • nishimurai. Aenictus nishimurai Terayama & Kubota, 1993: 70, figs. 9, 10 (w.) THAILAND. See also: Jaitrong & Yamane, 2012: 61.

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

Description

Worker

Jaitrong & Yamane (2012) - Paratype: TL 2.40 mm; HL 0.58 mm; HW 0.48 mm; SL 0.25 mm; ML 0.75 mm; PL 0.20 mm; CI 83; SI 53.

Larger workers (non-types, n = 7): TL 2.66-2.90 mm; HL 0.60-0.65 mm; HW 0.53-0.58 mm; SL 0.33-0.35 mm; ML 0.83-0.90 mm; PL 0.23-0.25 mm; CI 88; SI 61-64. Smaller workers (non-types, n = 4): TL 1.95-2.25 mm; HL 0.48-0.50 mm; HW 0.38-0.43 mm; SL 0.20-0.25 mm; ML 0.55-0.65 mm; PL 0.15-0.18 mm; CI 79-85; SI 53-59.

Head in full-face view longer than broad, with sides slightly convex and posterior margin almost straight or feebly concave; seen in profile occipital corner of head rounded. Antennal scape reaching midlength of head; antennal segment II almost as long as broad; III-VIII each slightly broader than long; terminal segment 2.3 times as long as broad. Anterior margin of clypeus bearing 7–10 denticles. Masticatory margin of mandible with 3 acute teeth including a large apical tooth; basal margin lacking denticles. Mesosoma seen in profile weakly convex dorsally or almost flat; in profile propodeum almost flat dorsally; suture between mesopleuron and metapleuron absent; propodeal junction dully angulated, forming an almost right angle; declivity of propodeum shallowly concave, encircled by a thin rim. Petiole nearly as long as high, its dorsal outline convex; subpetiolar process well developed, subrectangular, its ventral margin nearly straight and longer than posterior margin; postpetiole seen in profile almost as long as petiole, with round node.

Head including antennal scape entirely smooth and shiny; mandible finely striate with outer zone smooth and shiny. Dorsal and lateral surface of pronotum smooth and shiny except for anteriormost part microreticulate; mesothorax, metapleuron, and propodeum microreticulate. Petiole entirely microreticulate. Postpetiole microreticulate except for smooth and shiny area on dorsal surface.

Head and mesosoma dorsally with relatively sparse standing hairs mixed with sparse short hairs; longest pronotal hairs 0.15–0.18 mm. Head yellowish brown; mesosoma, petiole and postpetiole reddish brown; gaster yellowish brown, but paler than head.

Type Material

Jaitrong & Yamane (2012) - Holotype and 10 paratype workers NIAST, SKY Collection) from Thailand, Changmai Prov. [Chiangmai Prov.], Doi Suthep (1,500 m alt.), 18.VIII.1992, M. Terayama and S. Kubota leg. A paratype in SKY Collection was examined.

References

  • Jaitrong, W. & Yamane, S. (2012) Review of the Southeast Asian species of the Aenictus javanus and Aenictus philippinensis species groups (Hymenoptera, Formicidae, Aenictinae). ZooKeys 193: 49–78, doi: 10.3897/zookeys.193.2768.
  • Jaitrong, W., Yamane, S. & Chanthalangsy, N. (2011) The ant genus Aenictus from Laos, with description of a new species (Hymenoptera: Formicidae: Aenictinae). Journal of Asia-Pacific Entomology 14, 317-322.
  • Terayama, M.; Kubota, S. 1993. The army ant genus Aenictus (Hymenoptera: Formicidae) from Thailand and Viet Nam, with descriptions of three new species. Bull. Biogeogr. Soc. Jpn. 48: 68-72 (page 70, figs. 9, 10 worker described)