Anochetus strigatellus

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

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Specimen Labels

Nothing is known about the biology of this species.

Identification

Modified from Brown (1978) - This species is similar to Anochetus incultus and Anochetus modicus. It can be distinguished from the latter by the expanded frontal striation and the less reduced (longer) mesonotal disc, as well as by the fine, crisp propodeal striation and the darker body color.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Malaysia (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 strigatellus 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.

Diet. 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.

  • strigatellus. Anochetus strigatellus Brown, 1978c: 582 (w.) WEST MALAYSIA.

Description

Worker

Worker, holotype: TL 5.4, HL 1.28, HW 1.17, ML 0.80, WL 1.67, scape L 1.11, eye L 0.21 mm; CI 91, MI 63.

A slender, dark reddish-brown species resembling Anochetus incultus from the Philippines but with extensive frontal striation fanning out over the central vertex, with the disc of the pronotum smooth and shining (inside some peripheral striation), and with the propodeal dorsum longitudinally sulcate and transversely, distinctly but finely striate (ca. 40 striae, plus several more on the propodeal declivity).

The frontal striation reaches back to within 0.2 mm of the nuchal carina. Cervix and front slope of pronotal disc transversely striate; lateral margins of disc diagonally striate; lower sides of pronotum smooth and shining. Mesonotal disc about 3x as wide as long, convex in side view, with a moderately distinct anterior rim, transversely striate, Metanotal saddle with brief but coarse, mainly longitudinal costulae. Mesopleura smooth and shining, with a nearly complete transverse suture. Metapleura smooth and shining except for short diagonal striation along anteroventral and posterodorsai borders. Scapes surpass posterior borders of «occipital» lobes by about 0.1 mm when head is viewed in perfect full-face.

Petiole with node slender, evenly tapered to a narrowly rounded apex in side view; anterior slope nearly perfectly straight, posterior slope feebly convex. In front view, node with weakly convex sides, but tapered rapidly and convexly above mid-height to a blunt, narrowly rounded apex, with just a hint of nippling near apex; almost no anterior peduncle. Gaster slender, not constricted behind first segment.

Standing hairs fairly abundant, fine, 0.1 to 0.2 mm long on gaster and pronotum, but mostly shorter elsewhere; fairly long hairs on anterior underside of head and anterior procoxae; some oblique hairs on scapes and legs. Mandibles and femora with short, sparse, appressed to decumbent pubescence; antennae and extremities of legs with shorter but dense pubescence.

The paratypes are similar to the holotype, but are very slightly smaller; discrepancies in TL are due to different shrinkage of the gaster. TL 5.2-5.5, HL 1.24-1.26, HW 1.13-1.15, ML 0.79 in all, WL 1.57-1.64, scape L 1.10-1.11, eye L 0.20 mm in all; CI 90-91, MI 63-64.

Type Material

Holotype The Natural History Museum and 5 paratype workers (BMNH and Museum of Comparative Zoology) taken together, labeled "Trengganu, Malaya, II 1974, T. Clay."

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 582, worker described)