Anochetus paripungens

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Anochetus paripungens
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Anochetus
Species: A. paripungens
Binomial name
Anochetus paripungens
Brown, 1978

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Anochetus paripungens ANIC32-015892 top 25-AntWiki.jpg

Anochetus paripungens is restricted to the Top End of the Northern Territory where it is found primarily in rainforest sites (with only a few records from savannah woodlands). Most specimens are encountered as foragers in leaf litter. Nests are in soil generally under objects, in rotten wood and in termite nests. The type series of this species was found nesting in a rotten log which it shared with an Anochetus graeffei colony.

Identification

Propodeal angles produced as spines which are angled slightly posteriorly, the posterior face of the propodeum forming angle at the base of the spines; sculpture on front of head extending well beyond eyes and ending approximately half-way between eyes and posterior margin; pronotum shining with scattered shallow, oval shaped punctures; hind tibiae with semi-erect hairs restricted to the inner surfaces. This species is most similar to Anochetus wiesiae but differs in having a more lightly coloured body, shallow punctures on the dorsum of the pronotum, more posteriorly directed propodeal spines, a narrower petiolar node with less angular sides, and the lack of erect hairs on the outer surfaces of the hind tibiae. It is also only known from the Top End of the Northern Territory while A. wiesiae occurs on coastal Queensland.

Keys including this Species

Distribution

Northern Australia.

Distribution based on Regional Taxon Lists

Australasian Region: Australia (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Not much is known about the the biology of Anochetus paripungens 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

Queen and male unknown.

Nomenclature

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

  • paripungens. Anochetus paripungens Brown, 1978c: 596, fig. 35 (w.) AUSTRALIA. See also: Shattuck & Slipinska, 2012: 15.

Type Material

Holotype one of 13 workers selected from a small nest series taken in a rotten log in shady gallery forest at Howard Springs, Darwin area, Northern Territory, Australia, 7-8 July 1951, by W. L. Brown, Jr. and W. Bateman. In the same log we found a colony of Anochetus graeffei. The type locality, on the Howard River, was at the Darwin water supply source in 1951. I returned to this place in 1972, but found that it had been transformed into a public park and campground, so that the habitat was largely destroyed.

Description

Worker

Worker, holotype: TL 5.2, HL 1.28, HW 1.18, ML 0.70, scape L 1.05, eye L 0.22, WL 1.64 mm; CI 92, MI 55.

Worker paratypes: TL 5.0-5.2, HL 1.24-1.31, HW 1.13-1.20, ML 0.70-0.72, scape L 1.01-1.07, eye L 0.21-0.22, WL 1.55-1.64 mm; CI 91-92, MI 55-56.

Head with mandibles and antennae much as in Anochetus rectangularis, but the eyes a little smaller, more nearly circular, strongly convex. Antennal scapes just barely surpassing posterior margin of occipital lobe in full-face view. Frontal striation more extensive than in rectangularis, reaching a bit more than halfway from the eyes to the nuchal carina in the middle. Mandibles with straight, cultrate dorsomedial margin and obscurely crenulate ventromedial margin; preapical angle present but weak; preapical excision small; intercalary apical tooth conical, arising from near base of ventral apical tooth. Upper inner temporal areas, just beyond oblique field of frontal striation, with numerous small punctures; head otherwise generally smooth and shining.

Antennae slender; funicular segments II, III and IV together about twice as long as I; IV about twice as long as broad, and slightly longer than II. Scapes surpassing posterior border of «occipital» lobe by only about their apical thickness when the head is seen in perfect full-face view.

Trunk, petiole and gaster shown in fig. 35; notable are the small but sharp teeth on the propodeal angles and the strong, divergent teeth extending the free corners of the petiolar node, as shown in fig. 35. Pronotum with 5 sharp costulae running around anterior slope, otherwise smooth and shining, with numerous small, separated punctures on disc. Mesonotal disc more than twice as broad as long, nearly smooth, shining. Propodeum coarsely, transversely striate (or costulate) over dorsal surface, its sides smooth and shining, as are petiolar node and gaster. Mandibles and femora smooth, shining, sparsely punctulate; scapes and tibiae more densely, but very finely punctulate, moderately shining; tarsi and funiculi densely punctulate and opaque or nearly so.

Pubescente sparse on dorsal surfaces of body and undersides of head and fore coxae, especially sparse on gaster, consisting of fine, inconspicuous, appressed and decumbent hairs. Erect hairs fine, tapered, sparsely arranged along median third of head, anterior underside of head, posterior vertex, and frontal carinae; about 14 on pronotum and mesonotum (10-18 in paratypes); more and longer hairs on upper and lower surfaces of gaster (few on sides of gaster); a few scattered erect hairs on scapes, anterior sides of fore coxae and flexor surfaces of femora, as well as inner ventral margins and apices of mandibles.

Color castaneous (dull brownish-orange); middle of vertex, mesopleura and gaster darker reddish-brown; posterior corners of head, mandibles, petiole and legs ferruginous yellow.

Description from Shattuck & Slipinska (2012):

Worker description. Sculpturing on front of head extending approximately half-way between the level of the eyes and posterior margin. Scapes not reaching posterolateral corners ('lobes') of head; with abundant, appressed pubescence and a limited number of erect hairs. Eyes relatively small (EL < 0.22mm). Pronotum shining and with scattered, weak, oval shaped punctures. Mesonotum smooth and shining. Anterior section of pronotum with transverse wrinkles and ridges. Propodeum with angles produced as spines. Dorsum of propodeum rounded laterally, sculptured with coarse transverse striations and with inclined erect hairs. Metapleuron mostly smooth and shining. Dorsolateral corners of petiolar node with long spines. Hind tibiae with semierect hairs restricted to the inner surfaces. Colour brown, head, antennae and mandibles yellow-brown, legs yellow.

Measurements. Worker (n = 5): CI 90–93; EI 16–18; EL 0.19–0.21; HL 1.24–1.31; HW 1.12–1.21; HFL 1.11–1.14; ML 1.40–1.50; MandL 0.68–0.72; MTL 0.79–0.84; PronI 54–57; PronW 0.63–0.67; SL 1.04–1.11; SI 91–93.

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 596, fig. 35 worker described)
  • Shattuck, S.O. & Slipinska, E. 2012. Revision of the Australian species of the ant genus Anochetus (Hymenoptera Formicidae). Zootaxa 3426, 1–28.