Aenictus breviceps

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Aenictus breviceps
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Aenictus
Species: A. breviceps
Binomial name
Aenictus breviceps
Forel, 1912

Aenictus breviceps casent0905999 p 1 high.jpg

Aenictus breviceps casent0905999 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Aenictus breviceps.

Identification

A member of the laeviceps species group. Jaitrong and Yamane (2011) - This species has been confused with the closely related Aenictus laeviceps, and has been synonymized with it in the past. However, it can be distinguished from the latter as follows: mesonotum, metanotum, and propodeum partly smooth and shiny in A. breviceps (entirely punctate in A. laeviceps); propodeal junction rounder than in A. laeviceps; pronotum with 2–4 hairs (without hairs in A. laeviceps, but in 2 colonies, SU07-SKY-199 and SU08-Kei282, from Sumatra pronotum with 2 standing hairs). A. breviceps is also quite similar to Aenictus sonchaengi and Aenictus rotundicollis, all sharing the same number of standing hairs (2) on the vertex. However, this species is separated from A. sonchaengi by the condition of hairs on the pronotum (2–4 standing hairs in A. breviceps; more than 4 hairs in A. sonchaengi). A. breviceps and A. rotundicollis share the pronotum with 2–4 standing hairs, but the promesonotum in profile is much more weakly convex in A. breviceps than in A. rotundicollis and A. sonchaengi. Aenictus laeviceps occurs from eastern Thailand to the Philippines except on Java, and sympatric with A. sonchaengi in southern Thailand and Borneo, and with A. rotundicollis in Borneo. Aenictus breviceps, on the other hand, is confined to Java.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Indonesia (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 breviceps. 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.

  • breviceps. Aenictus fergusoni var. breviceps Forel, 1912d: 105 (w.) INDONESIA (Java). Junior synonym of laeviceps: Wilson, 1964a: 467. Revived from synonymy and raised to species: Jaitrong & Yamane, 2011: 32.

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

Description

Worker

Jaitrong and Yamane (2011) - Measurements. Worker lectotype and paralectotypes (n = 7): TL 3.75–3.95 mm; HL 0.80–0.85 mm; HW 0.70–0.75 mm; SL 0.70–0.73 mm; ML 1.25–1.27 mm; PL 0.25–0.28 mm; CI 85–94; SI 96–103.

Redescription(lectotype and paralectotypes). Head in full-face view slightly longer than broad, with sides and posterior margin slightly convex; occipital margin carinate, but not forming a collar. Antenna long; scape relatively long, almost reaching the posterolateral corner of head; antennal segments II–X each longer than broad, II almost as long as each of III and IV. Frontal carina short, not extending beyond the posterior margin of torulus; parafrontal ridge absent. Anterior margin of clypeus bearing 7–8 denticles. Masticatory margin of mandible with a large apical tooth followed by a medium-sized subapical tooth, 4–6 denticles and a medium-sized basal tooth; basal margin bearing 1–2 denticles. Promesonotum in profile convex dosally; propodeum distinctly lower than promesonotum, and in profile its dorsal outline almost straight; propodeal junction angulate; with propodeum in profile declivity straight. Petiole almost as long as high, in profile its dorsal outline weakly convex; subpetiolar process well developed, its lobe surmounted by a thin, acute flange that is directed downward and backward; postpetiole almost as long as petiole, with its node strongly convex dorsally.

Head entirely smooth and shiny. Mandible punctate except on masticatory and outer margins. Antennal scape shagreened with smooth and shiny interspaces. Pronotum smooth and shiny, its anteriormost portion punctate, and lateral face irregularly sculptured in anterior portion; mesopleuron sculptured; anepisternum with several irregular longitudinal rugulae, while katepisternum with dense punctures; metapleuron almost smooth and shiny except for posterior portion punctate; propodeal dorsum almost smooth and shiny except for areas in front of propodeal junction which is macroreticulate with smooth and shiny bottoms; area below propodeal spiracle punctate. Petiole shagreened with smooth and shiny interspaces. Postpetiole entirely very superficially microsculptured and shiny.

Head with a pair of standing hairs on vertex; mesosoma with 2–3 standing hairs on promesonotum. Entire body dark reddish-brown. Typhlatta spot located anterior to occipital corner.

Type Material

Jaitrong and Yamane (2011) - Aenictus fergusoni var. breviceps: Seven syntype workers on three pins (one on a pin, three on another, three on the other) from Java, Gunung Gedeh (The Natural History Museum, examined). One worker among them (middle on a pin) is selected as the lectotype, the others as paralectotypes.

References

  • Forel, A. 1912. Ameisen aus Java beobachtet und gesammelt von Edward Jacobson. III Theil. Notes from the Leyden Museum, 34, 97–112. (page 105, worker described)
  • 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.
  • Wilson, E. O. 1964a. The true army ants of the Indo-Australian area (Hymenoptera: Formicidae: Dorylinae). Pac. Insects 6: 427-483 (page 467, junior synonym of laeviceps)