Aenictus doryloides

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Aenictus doryloides
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Aenictus
Species: A. doryloides
Binomial name
Aenictus doryloides
Wilson, 1964

Nothing is known about the biology of Aenictus doryloides. It is only known from the type locality.

Identification

A member of the ceylonicus group. Jaitrong and Yamane (2013) – Aenictus doryloides is separated from the other species of the group by the following characteristics: anterior clypeal margin strongly concave, concealed by curved anterior extension of frontal carinae (the conformation of the anterior part of the head is, in fact, strongly reminiscent of some species of Dorylus) and mesosomal dorsum flat. It is very similar to Aenictus brevipodus.

Key to Aenictus species groups

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Oriental Region: India (type locality).


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 doryloides. 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.

Wilson 1964 Army Ant fig 51-57

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • doryloides. Aenictus doryloides Wilson, 1964a: 460, figs. 54, 55 (w.) INDIA.

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

Description

Worker

Holotype: HW 0.57 mm, HL 0.59 mm, SL 0.35 mm. Antenna 10-segmented, its scape both very short and incrassate. Mandibles narrow, strongly incurved, 3-toothed; in closure leaving a gap between their posterior borders and anterior clypeal border nearly as wide as their maximum width. Clypeus strongly emarginate, unarmed. The conformation of the anterior part of the head is, in fact, strongly reminiscent of some species of Dorylus, hence the name proposed here. Parafrontal ridge absent. Occiput straight, lacking a collar. Propodeal junction smoothly rounded. Subpetiolar process large, consisting of a rectangular base, which is forward-projecting, surmounted by a thin, acute, posteriorly directed flange. Pilosity moderately abundant, the length of the longest pronotal hairs about 0.15 mm.

Head shining. Dorsa of pronotum and mesonotum shining. Sides of pronotum feebly microreticulate (reticular diameters about 0.01 mm) and feebly shining. Remainder of mesosoma more strongly microreticulate (i. e., reticulum more raised) and opaque. Dorsum of postpetiole shining; remainder of pedicel microreticulate and opaque. Concolorous light reddish brown.

Paratypes: 2 workers, HW 0.54 and 0.56 mm, differing little from holotype.

Jaitrong and Yamane (2013) - (holotype and 2 paratypes). TL 2.70–2.90 mm; HL 0.58–0.63 mm; HW 0.55–0.58 mm; SL 0.38–0.39 mm; ML 0.83–0.88 mm; PL 0.25–0.28 mm CI 92–96; SI 67–68.

Head in full-face view subrectangular, slightly longer than broad, sides weakly convex and posterior margin almost straight or feebly convex. Antennal scape relatively short, reaching only half length of head; antennal segment II slightly longer than broad; III-VII almost as long as broad; X almost as long as VII+VIII+IX. Frontal carinae relatively short, slightly extending beyond the level of posterior margin of torulus. Parafrontal ridge absent. Anterior clypeal margin strongly concave, concealed by curved anterior extension of frontal carinae. Masticatory margin of mandible with 3 teeth including a large apical tooth; basal margin concave. Maximum width of gap between anterior clypeal margin and mandibles almost as wide as maximum width of mandible. Promesonotum almost flat; metanotal groove indistinct; mesopleuron not clearly demarcated from metapleuron; metapleural gland bulla relatively small, its maximum diameter 2.4 times as long as distance between propodeal spiracle and metapleural gland bulla. Propodeum in profile with straight dorsal outline; propodeal junction bluntly angulate; declivity of propodeum widely and shallowly concave, encircled with a thin rim. Petiole slightly longer than high, with its dorsal outline convex; subpetiolar process large, consisting of a rectangular base, which is forward-projecting, surmounted by a thin, acute, posteriorly directed flange. Postpetiole shorter than petiole, with its dorsal outline convex.

Head including antennal scape entirely smooth and shiny. Mandible with fine longitudinal striation, except along masticatory margin smooth and shiny. Dorsa of pronotum and mesonotum smooth and shiny; lateral face of pronotum feebly microreticulate and feebly shiny; remainder of mesosoma more strongly microreticulate and opaque. Petiole and postpetiole microreticulate except dorsa smooth and shiny. Legs entirely smooth and shiny.

Head with relatively sparse standing hairs mixed with dense short hairs over surface; mesosoma dorsally with relatively sparse standing hairs mixed with sparse decumbent hairs; longest pronotal hair 0.15–0.18 mm long. Head, mesosoma, petiole, and postpetiole reddish brown; gaster and legs yellowish brown; mandible dark brown.

Type Material

Type locality: Solon, 1400 rn, nr Simla, NC India, 8. VilL 1944 (L. Weatherill, ace. no. 9).

References

  • Jaitrong, W. & Yamane, S. 2011. Synopsis of Aenictus species groups and revision of the A. currax and A. laeviceps groups in the eastern Oriental, Indo-Australian, and Australasian regions (Hymenoptera: Formicidae: Aenictinae). Zootaxa, 3128, 1–46. PDF
  • Wilson, E. O. 1964a. The true army ants of the Indo-Australian area (Hymenoptera: Formicidae: Dorylinae). Pac. Insects 6: 427-483 (page 460, figs. 54, 55 worker described)