Nothing is known about the biology of Anochetus gracilis.
Chen et al. (2019) - China: Syntype worker images of Anochetus risii and Anochetus gracilis from AntWeb show the following differences: 1) inner margin of mandibles with no denticles in the worker of Anochetus gracilis, but possesses several distinct denticles in the worker of Anochetus risii; 2) the maximum diameter of eye is much larger than the maximum width of mandible in the worker of Anochetus gracilis, but smaller than or just equal to maximum width of mandible in the worker of Anochetus risii; 3) pronotal sides distinctly striate in the worker of Anochetus gracilis, but smooth and shining in the worker of Anochetus risii.
Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
Check data from AntWeb
Not much is known about the the biology of Anochetus gracilis 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.
The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.
- gracilis. Anochetus gracilis Karavaiev, 1925c: 286, fig. 9 (w.q.) INDONESIA (Java).
- Type-material: syntype workers, syntype queens (numbers ot stated).
- Type-locality: Indonesia: Java, Buitenzorg (= Bogor), Botanical Gardens, Nr. 2416 (W. Karawaiew).
- Type-depository: SIZK.
- Junior synonym of risii: Brown, 1978c: 558; Bolton, 1995b: 64; Zhou, 2001b: 29.
- Status as species: Chapman & Capco, 1951: 39; Chen, Yang & Zhou, 2019: 70.
- Distribution: Indonesia (Java).
- 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. Studia Entomologica. 20:549-638. (page 558, junior synonym of risii)
- Chen, Z., Yang, Z., Zhou, S. 2019. Review of the ant genus Anochetus Mayr, 1861 (Hymenoptera, Formicidae) from China, with revival of the valid status of Anochetus gracilis. Journal of Hymenoptera Research 68: 49–74 (DOI 10.3897/jhr.68.30784).
- Karavaiev, V. 1925c. Ponerinen (Fam. Formicidae) aus dem Indo-Australischen Gebiet. (Schluss). Konowia 4: 276-296 (page 286, fig. 9 worker, queen described)
References based on Global Ant Biodiversity Informatics
- CSIRO Collection
- Chapman, J. W., and Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327
- Chen Z., Z. Yang, and S. Zhou. 2019. Review of the ant genus Anochetus Mayr, 1861 (Hymenoptera, Formicidae) from China, with revival of the valid status of Anochetus gracilis. Journal of Hymenoptera Research 68: 49–74.
- Karavaiev V. 1925. Ponerinen (Fam. Formicidae) aus dem Indo-Australischen Gebiet. (Schluss). Konowia 4: 276-296.
- Karavaiev V. 1926. Ameisen aus dem Indo-Australischen Gebiet. Treubia 8: 413-445.