Anochetus brevis

AntWiki - Where Ant Biologists Share Their Knowledge
Jump to: navigation, search
Anochetus brevis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Anochetus
Species: A. brevis
Binomial name
Anochetus brevis
Brown, 1978

Anochetus brevis casent0902439 p 1 high.jpg

Anochetus brevis casent0902439 d 1 high.jpg

Specimen Labels

This species is only known from type specimens.

Identification

See the description below for distinguishing characteristics and Zettel (2012) for a key to Philippine Anochetus.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Philippines (type locality).

Distribution based on AntMaps

AntMapLegend.png

Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Not much is known about the the biology of Anochetus brevis but we can presume that its biology is similar to other Anochetus species. The following account of Anochetus biology is modified from Brown (1968):

Habitat. The places where Anochetus live are varied. Where they penetrate into the temperate zone, most species excavate nests in the earth. Occasionally the nest is dug under a covering rock. In the tropics, many nests are also dug in the soil, but in moist forested areas, a common site is the soil beneath a rotting log or other large mass of rotting wood, with extensions of the nest into the log itself. Another frequent nesting site in tropical forest is in the humus and leaf litter at the base of large trees, particularly between buttress roots. Anochetus species of medium or small size often nest in small pieces of rotting wood or bark, or even small rotting twigs or seeds and nuts lying in or on the forest litter. Some species tend to choose more arboreal nest sites.

Foraging for living animal prey takes place on the soil surface, within the soil-humus-log mold matrix, or on the trunks, branches and foliage of trees and plants wherever these are available. Fragmentary evidence indicates that most epigaeically foraging tropical Anochetus tend to do their foraging at dusk, at night, or during dawn hours. I found Anochetus africanus walking on tree trunks only at night in the Ivory Coast. Some species, particularly those with red heads or other aposematic coloration, apparently forage in the open more during the day. No systematic comparative study has yet been made of foraging hours for different species.

The food of Anochetus consists principally of living arthropods caught and killed or incapacitated by the ants. The smaller and more delicate species Anochetus inermis has been observed by me in a laboratory nest. The colony came from a piece of rotten wood from the floor of a wet ravine near Bucay in western Ecuador. The colony was fed with small tenebrionid beetle larvae (Tribolium castaneum), comparable in size to the A. inermis workers, and the latter attacked the prey with their mandibles in the familiar snapping manner, but very cautiously and nervously, with stealthy approach, extremely rapid strike, and instant recoil-retreat. After several attacks of this kind, with intervening periods of waiting, during which the beetle larvae fled, rested, or writhed about in distress, an ant would finally attack with its mandibles and hold them closed on the prey for long enough to deliver a quick sting in the intersegmental membrane. After this, the prey appeared to be paralyzed, or at least subdued, and sooner or later was carried off by the ant to the nest, and eventually placed on an ant larva. Frequent delays and excursions before the prey are finally immobilized and brought to the ant larvae in the nest may well have the function of allowing time for protective allomones of the prey to dissipate. Many tenebrionid adults, including Tribofium, possess potent quinonoid defensive allomones, but the larva is not known to possess quinones in this genus.

Nuptial flight. Although males of different species of Anochetus are commonly taken at light, other species are not. Stewart and Jarmila Peck gave me Malaise trap samples taken in western Ecuador that contained males of several species, but Malaise traps capture both day- and night-flying insects.

Defense. When a nest of any of the larger Anochetus species is breached, some of the workers immediately hide beneath leaves or other objects, while other workers rush about with open jaws, which they snap at foreign objects, or even at leaves and twigs, with an audible tick. On human skin or clothing, a worker will snap her jaws and hold fast to the surface with them, at the same time quickly bringing her gaster around to sting. The sting is long and strong, and to me the effect is shocking and quickly painful.

Most of the smaller and medium-sized Anochetus species feign death when disturbed, crouching flat against the surface, or rolling themselves into a ball and remaining still, often for a minute or more. Only when held do they sting. Their stings can be felt in most cases, but the effect is usually trifling.

Castes

Queens and males of this species are unknown.

Nomenclature

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

  • brevis. Anochetus brevis Brown, 1978c: 581, fig. 2 (w.) PHILIPPINES.

Description

Worker

Worker, holotype: TL 5.0, HL 1.20, HW 1.08, ML 0.61, WL 1.52, scape L 0.94, eye L 0.13 mm; CI 90, MI 50.

Paratype worker: TL 5.2, HL 1.21, HW 1.07, ML 0.60, WL 1.53, scape L 0,96, eye L 0.14 mm; CI 88, MI 50.

With the general characters of the risii group, but mandibles very short, relatively broad toward apices; light brownish-red in color, mandibles and antennae more yellowish. In body form and sculpture like a short-mandibulate Anochetus modicus, but the following additional differences from A. modicus:

1. Frontal striation obsolete, even inside frontal carinae. Pronotum completely smooth and shining, except for finely transversely striate cervix.

2. Mesonotal disc longer, elliptical, only twice as broad as long, convex, smooth and shining. Anterior edge blunt. Mesonotal saddle only a brief shallow groove, with longitudinal costulae represented only by tiny, indistinct, raised tubercles; area behind this, grading onto propodeal dorsum, vaguely diagonally costulate; propodeal dorsum transversely striate (about 20 striae).

3. Crenulation of ventral mesial margin of mandible reduced, fine, developed only near preapical tooth or angle.

4. Petiolar node like that of A. modicus, tall and slender, with narrowly rounded apex, but the anterior and posterior slopes in side view nearly perfectly straight in the upper 2/3. As seen from front, lower halves of node nearly parallel, upper halves convexly rounded and rapidly tapered to narrowly rounded apex, with just a hint of nippling near apex. Brief anterior peduncle present.

Meso- and metapleura smooth and shining except for borders of short striae along the anteroventral edges and posterior ends of the metapleura; mesopleuron with distinct transverse suture. Head, mandibles, legs (except finely punctulate tibiae and tarsi), node and gaster smooth and shining. Standing hairs numerous, fine and generally distributed over dorsal surfaces of body, underside of gaster, scapes and legs, mostly about 0.05 mm long, but 0.1 mm or longer on pronotum and gastric dorsum (many longer in A. modicus). Underside of head with moderately abundant suberect pubescence; mandibles with fine appressed pubescence; antennae and legs with fine, dense, decumbent pubescence (sparse on femora).

Type Material

Holotype Museum of Comparative Zoology and a paratype The Natural History Museum very similar workers taken together on Mt. Apo, Mindanao Island, southern Philippines at 5-6000 ft (~1520-1830 m), by C. F. Clagg.

References

  • Brown, W. L., Jr. 1978c. Contributions toward a reclassification of the Formicidae. Part VI. Ponerinae, tribe Ponerini, subtribe Odontomachiti. Section B. Genus Anochetus and bibliography. Stud. Entomol. 20: 549-638 (page 581, fig. 2 worker described)
  • General, D. and G. Alpert. 2012. A synoptic review of the ant genera (Hymenoptera, Formicidae) of the Philippines. ZooKeys. 200:1-111 doi: 10.3897/zookeys.200.2447.
  • Zettel, H. 2012. New trap-jaw ant species of Anochetus MAYR, 1861 (Hymenoptera: Formicidae) from the Philippine Islands, a key and notes on other species. Myrmecological News 16: 157-167.