Aenictus khaoyaiensis

Aenictus khaoyaiensis
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Dorylinae
Genus:	Aenictus
Species:	A. khaoyaiensis
Binomial name
Aenictus khaoyaiensis Jaitrong & Yamane, 2013

This species inhabits both lowland primary and disturbed forests.

Identification

A member of the ceylonicus group. Aenictus khaoyaiensis is similar to Aenictus watanasiti.

Keys including this Species

• Key to southeastern Asian Aenictus ceylonicus group species

Distribution

Distribution based on Regional Taxon Lists

Oriental Region: Thailand (type locality).

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Explore Overview of Aenictus biology  Little is known about the biology of Aenictus khaoyaiensis. The genus is comprised of species that live an army ant lifestyle. Aenictus typically prey on other ants, from other genera, or other insects such as wasps or termites. There are reports of Aenictus preying on other insects as well and even have been observed collecting honeydew from homopterans (Santschi, 1933; Gotwald, 1995) but this appears, at least from available evidence, to be uncommon. Foraging raids can occur day or night across the ground surface. Occasionally raids are arboreal. During a raid numerous workers attack a single nest or small area, with several workers coordinating their efforts to carry large prey items back to the nest or bivouac. Aenictus have a nomadic life style, alternating between a migratory phase in which nests are temporary bivouacs in sheltered places above the ground and a stationary phase where semi-permanent underground nests are formed. During the nomadic phase bivouacs move regularly, sometimes more than once a day when larvae require large amounts of food. Individual nests usually contain up to several thousand workers, although nest fragments containing only a few hundred workers are often encountered. Queens are highly specialised and look less like workers than in most ant species. They have greatly enlarged gasters (dichthadiform) and remain flightless throughout their life. New colonies are formed by the division of existing colonies (fission) rather than by individual queens starting colonies on their own. ‎

Castes

Known only from the worker caste.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

• khaoyaiensis. Aenictus khaoyaiensis Jaitrong & Yamane, 2013: 194, fig. 10A-C (w.) THAILAND.
  • Type-material: holotype worker, 44 paratype workers.
  • Type-locality: holotype Thailand: Nakhon Ratchasima Prov., Khao Yai N.P., 31.v.2000, TH00-SKY-35, tropical rainforest (Sk. Yamane); paratypes with same data.
  • Type-depositories: TNHM (holotype); BMNH, MCZC, SKYC, TNHM (paratypes).
  • Status as species: Khachonpisitsak, et al. 2020: 28.
  • Distribution: Thailand.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

(holotype and paratypes, n = 10). TL 2.45–3.00 mm; HL 0.50–0.60 mm; HW 0.48–0.60 mm; SL 0.38–0.43 mm; ML 0.78–0.93 mm; PL 0.21–0.25 mm; CI 95–100; SI 65–79.

Head in full-face view subrectangular, almost as long as broad, sides weakly convex, posterior margin almost straight or feebly concave. Antennal scape relatively short, slightly extending beyond 1/2 of head length. Frontal carina relatively long, slightly extending beyond the level of posterior margin of torulus. Parafrontal ridge almost absent. Anterior clypeal margin feebly concave, concealed by curved anterior extension of frontal carina. Masticatory margin of mandible with 4 denticles, including a large apical tooth; basal margin feebly concave. Maximum width of gap between anterior clypeal margin and mandibles about 2.8 times as broad as maximum width of mandible. Promesonotum strongly convex dorsally and sloping gradually to metanotal groove; mesopleuron demarcated from metapleuron by a shallow groove; metapleural gland bulla relatively large, its maximum diameter 2.3–2.8 times as long as distance between propodeal spiracle and metapleural gland bulla. Propodeum in profile extremely lower than pronotum and relatively short with feebly convex dorsal outline; propodeal junction angulate, overhanging the declivitous face of propodeum; the declivity broadly and shallowly concave, encircled with a distinct rim. Petiole almost as long as high, with its dorsal outline slightly elevated posteriorly; subpetiolar process low, with its anteroventral corner angulate and ventral margin weakly convex. Postpetiole subrectangular, almost as long as petiole, with its dorsal outline slightly elevated posteriorly.

Head entirely smooth and shiny. Mandible very finely striate. Antennal scape superficially sculptured but somewhat shiny. Promesonotum smooth and shiny except for anteriormost portion punctate; mesopleuron wrinkled and reticulate; in addition mesopleuron with several irregular longitudinal rugae; metapleuron reticulate partly smooth and shiny; petiole entirely reticulate; postpetiole reticulate except for dorsal faces smooth and shiny. Legs smooth and shiny except basalmost portions of femora and tibiae micropunctate.

Head and mesosoma dorsally with relatively sparse standing hairs mixed with relatively dense decumbent hairs; longest pronotal hair 0.18–0.20 mm long. Head including mandible and antennal scape, gaster and legs yellowish brown; mesosoma, petiole and postpetiole reddish brown but petiole and postpetiole paler than mesosoma.

Type Material

Holotype. THAILAND: Worker from NE. Thailand, Nakhon Ratchasima Prov., Khao Yai N.P., tropical rainforest, 31.V.2000, leg. Sk. Yamane, TH00-SKY-35 (THNHM). Paratypes. Forty-four workers, same data as holotype (BMNH, MCZC, SKYC, THNHM).

Etymology

The specific name is after the type locality, Khao Yai National Park, northeastern Thailand.

References

• Dhadwal, T., Bharti, H. 2023. Aenictus dirangensis sp. nov. (Hymenoptera: Formicidae), a new species of Aenictus ceylonicus group from India. Journal of the Entomological Research Society 25(2): 387-403 (doi:10.51963/jers.v25i2.2367).
• Jaitrong, W. & Yamane, S. 2013. The Aenictus ceylonicus species group (Hymenoptera, Formicidae, Aenictinae) from Southeast Asia. Journal of Hymenoptera Research 31:165-233.
• Khachonpisitsak, S., Yamane, S., Sriwichai, P., Jaitrong, W. 2020. An updated checklist of the ants of Thailand (Hymenoptera, Formicidae). ZooKeys 998, 1–182 (doi:10.3897/zookeys.998.54902).

References based on Global Ant Biodiversity Informatics

• Borowiec M. L. 2016. Generic revision of the ant subfamily Dorylinae (Hymenoptera, Formicidae). ZooKeys 608: 1–280.
• Jaitrong W. 2015. A revision of the Thai species of the ant genus Aenictus Shuckard, 1840 (Hymenoptera: Formicidae: Dorylinae). The Thailand Natural History Museum Journal 9(1): 1-94.
• Jaitrong W., and S. Yamane. 2013. The Aenictus ceylonicus species group (Hymenoptera, Formicidae, Aenictinae) from Southeast Asia. Journal of Hymenoptera Research 31: 165-233.