Aenictus powersi

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Aenictus powersi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Aenictus
Species: A. powersi
Binomial name
Aenictus powersi
Wheeler, W.M. & Chapman, 1930

Aenictus powersi casent0217383 p 1 high.jpg

Aenictus powersi casent0217383 d 1 high.jpg

Specimen Labels

The type series was collected from beneath a piece of wood in a garden.

Identification

A member of the pachycerus group.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Philippines (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 powersi. 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 76-83

Nomenclature

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

  • powersi. Aenictus (Aenictus) powersi Wheeler, W.M. & Chapman, in Wheeler, W.M. 1930g: 210, fig. 6 (w.) PHILIPPINES. See also: Wilson, 1964a: 475.

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

Description

Worker

WORKER. Length 2.5-3 mm.

Head scarcely longer than broad, subrectangular, nearly as broad behind as in front, with feebly rounded sides and straight posterior border, the posterior corners rounded, not produced. Frontal and genal carinae very short, the latter not dentate. Clypeus concave, with narrow, translucent anterior border, sub triangular, with a large blunt apical tooth and several minute, irregular basal dentides on the terminal border, the external border convex. Antennae short, the scapes thickened apically, reaching to the posterior third of the head, first funicular joint small, as long as broad, joints 2-8 slightly broader than long, terminal joint a little longer than the two penultimate joints together. Pronotum slightly flattened above, the mesonotum short, sloping to the mesoepinotal constriction, which is moderately pronounced. Epinotum with convex base and concave declivity, the boundary between the two developed as a blunt point. Petiole nearly as broad as long, its node evenly rounded and hemispherical, the ventral surface with a transparent lamina, produced behind as a downwardly and backwardly directed spine. Postpetiolar node resembling the petiolar node but somewhat broader and slightly broader than long, anteroventrally with a well developed tool;h, which is directed downward and forward. Gaster regularly elliptical. Legs with incrassated femora and tibae.

Mandibles opaque, finely and densely shagreened. Remainder of body smooth and shining, with fine, sparse, piligerous punctures, except the mesopleurae, mesoepinotal constriction, sides of epinotum and ventral surfaces of the petiole and postpetiole, which are sub opaque, finely and densely punctate.

Hairs white, uneven, rather delicate, sparse on the body, short on the appendages.

Mandibles, antennal fovere and anterior border of head reddish brown, remainder of head, antennal scapes and thorax yellowish red; pedicel, gaster and legs, including the coxre, yellow; antennal funiculi brown, except the terminal joint, which is yellowish red like the scapes.

Wilson (1964) - Syntypes: Worker selected at random: HW 0.78 mm, HL 0.74 mm, SL 0.45 mm. HW of 29 other syntypes 0.68-0.80mm. Antenna 10-segmented. Mandible typical in form; in closure leaving a small gap between its posterior border and anterior clypeal border. Clypeus convex, entire, unarmed. Parafrontal ridge weakly defined, only 0.12 mm long. Occiput straight, lacking collar. Basal face of propodeum straight. Propodeal junction smoothly rounded, with no trace of a ridge. Subpetiolar process very large, consisting of a subretangular lobe surmounted by a large, ventrally curving, acute flange. Pilosity sparse; only 10-25 hairs breaking the mesosomal profile. Length of longest pronotal hairs only about 0.25 mm.

Head shining, except for mandibles, which are microreticulate and opaque. Anterior face of pronotum, metanotum, mesopleuron, metapleuron, and sides of propodeum microreticulate and subopaque; remainder shining. Dorsum of pedicel shining; the rest microreticulate and opaque. Mostly clear medium yellow; parts of alitrunk with a brownish tinge.

Type Material

Described from several workers taken near Dumaguete at an altitude of 1,800 feet from a single colony under a piece of wood in a garden. This species is hypogaeic.

Type locality: Dumaguete, 540 m, Negros, P. I.

References

  • Chapman, J. W.; Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327 (page 12, checklist)
  • Jaitrong, W. & Wiwatwitaya, D. 2013. Two new new species of the Aenictus pachycerus species group (Hymenoptera: Formicidae: Aenictinae) from Southeast Asia. Raffles Bulletin of Zoology 61, 97-102.
  • Wheeler, W. M. 1930j. Philippine ants of the genus Aenictus with descriptions of the females of two species. J. N. Y. Entomol. Soc. 38: 193-212 (page 210, fig. 6 worker described)
  • Wilson, E. O. 1964a. The true army ants of the Indo-Australian area (Hymenoptera: Formicidae: Dorylinae). Pac. Insects 6: 427-483 (page 475, see also)