Aenictus chapmani

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

Aenictus chapmani casent0217374 p 1 high.jpg

Aenictus chapmani casent0217374 d 1 high.jpg

Specimen Labels

The type series was obtained from "several scattered files of workers were found crossing a native trail in second-growth forest during the early part of the night."

Identification

A member of the pachycerus group.

Distribution

Known from the Huon Peninsula, NE New Guinea and Duamagete, Philippines.

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo, Indonesia, Malaysia, New Guinea (type locality).

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Aenictus chapmani for further details

Biology

Little is known about the biology of Aenictus chapmani. 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 45-50

Nomenclature

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

  • chapmani. Aenictus chapmani Wilson, 1964a: 456, figs. 45, 46 (w.) NEW GUINEA.

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 0.72 mm, HL 0.76 mm, SL 0.70 mm. Antenna 10-segmented. Mandible somewhat narrower with reference to the head than in the "typical" form (e. g., in laeviceps and pachycerus), its maximum width 0.16 mm; indistinctly 3-toothed. In closure the mandibles leave a gap between their posterior margins and the clypeus of about 0.02 mm. Anterior clypeal border very feebly concave, unarmed. Parafrontal ridge 0.10 mm long, in side view prosalient as a narrow, irregular lobe. Occiput almost perfectly straight, lacking a collar. Posterior surface of petiolar node drawn into a low, obtuse angle. Main portion of subpetiolar process large, lobose, anteriorly directed; surmounted by a thin, acute flange which is posteriorly directed. Pilosity abundant; pronotal hairs up to 0.20 mm in length.

Head shining. Mesosoma almost entirely microreticulate (reticular diameter 0.01 mm) and opaque. Microreticulum on mesonotum weakly developed, the surface only subopaque. In addition the meso-, metathorax, and propodeum bear about 25 longitudinal rugae. Pedicel wholly microreticulate and opaque. Head, alitrunk, and pedicel rich medium reddish brown; gaster and appendages a contrasting light reddish brown.

Paratypes: 7 workers from same nest series show little deviation from holotype. HW 0.70-0.77 mm. One paratype chosen at random: HW 0.73 mm, HL 0.76 mm, SL 0.71 mm. Mandibles range from distinctly 3-toothed to distinctly 4-toothed, with intermediate development of the 4th tooth as 1 or 2 denticles between the preapical basal teeth.

Type Material

Zingzingu, 1200 m, Mongi Watershed, Huon Peninsula, NE New Guinea.

Etymology

This species is named for the late Dr J. W. Chapman, in recognition of his pioneering taxonomic and ecological studies of Philippine army ants.

References

  • Wilson, E. O. 1964a. The true army ants of the Indo-Australian area (Hymenoptera: Formicidae: Dorylinae). Pac. Insects 6: 427-483 (page 456, figs. 45, 46 worker described)