Anochetus incultus

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

Anochetus incultus casent0217506 p 1 high.jpg

Anochetus incultus casent0217506 d 1 high.jpg

Specimen Labels

The type material was collected from leaf litter samples.

Identification

Brown (1978) - Similar to Anochetus risii, but smaller and darker: deep reddish-brown, with mandibles, antennae, legs, cheeks and gastric apex lighter, more yellowish.

Zettel (2012) - Anochetus incultus is a species of the A. risii group (Brown 1978). It was described from five workers and a gyne from Mt. Makiling in Laguna Province; no further record was published. One examined worker from the type locality is much smaller than the types (TL 4.4 mm vs. 4.8-5.2 mm) and has a reduced sculpture on frons and pronotum, but is probably conspecific. The gyne from Quezon Province agrees well with the description of the paratype gyne (Brown 1978) except for smaller size (TL 5.0 mm vs. 5.6 mm).

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

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

Check distribution from AntMaps.

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Anochetus incultus for further details

Biology

Not much is known about the the biology of Anochetus incultus 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

Males are unknown for this species.

Worker

Nomenclature

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

  • incultus. Anochetus incultus Brown, 1978c: 578, fig. 37 (w.q.) PHILIPPINES.

Description

Worker

holotype: TL 5.2, HL 1.20, HW 1.07, ML 0.81, WL 1.66, scape L 1.08, eye L 0.17 mm; CI 89, MI 68.

Similar to Anochetus risii, but smaller and darker: deep reddish-brown, with mandibles, antennae, legs, cheeks and gastric apex lighter, more yellowish. Also the following differences:

1. Eyes smaller; EL/HL 0.14-0.16, vs. 0.17-0.20 in risii. Ocular prominences strongly projecting laterad.

2. Mandibles long, but not quite as long relatively as in risii, which has MI 72-77 in the few samples examined. Denticles on mesal ventral margins of mandibles small and blunt, ordinarily hidden beneath edentate dorsal margin when head is viewed full-face.

3. Pronotal disc behind anterior transverse costulation is shining but thickly covered discad with fairly coarse, vermiculate, predominantly longitudinal rugulae or costulae. Sides of pronotum obliquely to vertically rugulo-striate more finely, except for a variable lower posterior section that tends to be smooth and shining (Pronotal sculpture not shown in fig. 37). Mesonotum vaguely transversely rugulose, but longitudinally costulate behind, continuing into metanotal saddle (fig. 37), Mesopleura smooth and shining, except for striate posterior end.

4. Petiolar node in side view tapering evenly to a narrowly rounded summit (fig. 37); convex-sided in front view, then tapering to a rounded summit. Petiole with a longer anterior pedunculate section than in risii. Node (and gaster) smooth and shining.

5. Funicular antennomeres shorter than in risii; II through IV only about twice as long as broad, or slightly less (in risii L 2-3 times breadth for the same antennomeres).

6. Erect pilosity somewhat less abundant and shorter than in risii. Pubescence nearly obsolete except on appendages.

Worker paratypes (4): TL 4.9-5.2, HL 1.13-1.22, HW 1.01-1.09, ML 0.78-0.82, WL 1.53-1.70, scape L 1.01-1.09, eye L 0.16-0.20 mm; CI 89, MI 67-69.

Intercalary tooth of mandibular apex (on ventral apical tooth) may be missing or nearly so, apparently due to wear or breakage; fine and acute in one young specimen. Pronotal sculpture variable in orientation on pronotum; in one worker the rugulae form a transverse band across the posterior end of the disc.

Queen

dealate: TL 5.6, HL 1.24, HW 1.16, ML 0.82, WL 1.76, scape L 1.09, eye L 0.27 mm; CI 93, MI 66. Pronotum shining, transversely rugose or costate. Mesonotum smooth and shining. Frontal striation weak, fine, confined to space just inside frontal carinae; this striation more delicate in both worker and queen than in risii of corresponding castes. Petiolar node slightly thinner in side view than in workers; i.e., it is axially compressed, with anterior and posterior surfaces converging very gradually. Gaster larger than in worker.

Type Material

Holotype Museum of Comparative Zoology and 4 paratype workers (MCZC, The Natural History Museum), plus one dealate queen, all labeled as from Mt. Makiling, near Los Baños, Laguna Prov., Luzon, Philippines. A single paratype was collected (date not recorded) by F. X. Williams; the remainder of the specimens, including the holotype, came from two samples of leaf litter collected near the summit of the mountain in February and March 1968, run through the Berlese funnel by R. A. Morse.

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 578, fig. 37 worker, queen 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.