Aenictus vieti

Aenictus vieti
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Dorylinae
Genus:	Aenictus
Species:	A. vieti
Binomial name
	Aenictus vieti; Jaitrong & Yamane, 2010

The type specimens were collected from the highland of the northernmost part of Vietnam.

Identification

Jaitrong et al. (2010) - A member of the wroughtonii group. Aenictus vieti is closely related to Aenictus camposi, but is slightly larger than the latter in body length. It is easily distinguished from A. camposi; as follows: the subpetiolar process anteroventrally is clearly acutely angulate in A. vieti (unarmed in A. camposi) and the pronotum is demacated from mesonotum by a shallow transverse groove in A. vieti (groove indistinct in A. camposi).

Keys including this Species

Key to Aenictus wroughtonii group species

Distribution

Distribution based on Regional Taxon Lists

Oriental Region: Vietnam (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 vieti. 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.

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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.

vieti. Aenictus vieti Jaitrong & Yamane, in Jaitrong, et al. 2010: 44, figs. 11, 12, 15 (w.) VIETNAM.
- Type-material: holotype worker, 7 paratype workers.
- Type-locality: holotype Vietnam: Lao Cai, Sa Pa, 4.v.2002, Eg02-VN-272 (K. Eguchi); paratypes with same data.
- Type-depositories: IEVH (holotype); IEVH, SKYC, TNHM (paratypes).
- Status as species: Jaitrong & Ruangsittichai, 2018: 113 (in key); Khachonpisitsak, et al. 2020: 32.
- Distribution: Taiwan, Thailand, Vietnam.

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

Description

Worker

Worker (n = 11 including the Holotype and paratypes): TL 2.85-2.95 mm; HL 0.58-0.60 mm; HW 0.45-0.48 mm; 5L 0.58 mm; ML 0.98-1.00 mm; MTL 0.58-0.60 mm; PL 0.23 mm; CI 78-79; SI 121-128.

Head in full-face view elliptical, slightly longer than broad, with convex sides and almost straight posterior margin of head. Antennal scape long, reaching posterolateral comer of head; antennal segments II-X each longer than broad; II slightly shorter than III, but as long as each of IV-VI or more; the terminal segment (X) slightly longer than VIII and IX combined. Frontal carina long, extending posteriad beyond the posterior margin of antennal torulus. Clypeus short, with its anterior margin convex, bearing 8-10 denticles. Mandible with the apical tooth large and curved, followed by 10-12 minute teeth on masticatory margin. With mesosoma in profile, pronotum weakly convex dorsally, demarcated from mesonotum by a shallow transverse groove, mesonotum convex, promesonotum sloping gradually to metanotal groove. Propodeum slightly lower than promesonotum with its dorsal outline almost straight in profile; propodeal junction angulate; declivity of propodeum widely and shallowly concave, encircled with a thin rim. Petiole in profile slightly longer than high and somewhat rounded dorsally; subpetiolar process developed, with its ventral margin convex anteriorly and bearing a thin rim below, with the anteroventral corner acutely angulate; postpetiole slightly smaller than petiole; its node rounded dorsally and scarcely longer than broad.

Head smooth and shiny; antennal scape sparsely punctate. Pronotum smooth and shiny, with its anteriormost portion punctate; mesothorax, metapleuron and propodeum with dense microrecticulae and several rugae; dorsum and sides of propodeum with short longitudinal rugae along the angle. Dorsum of petiole and entire postpetiole smooth and shiny. Gaster, femora and tibiae smooth and shiny.

Body with relatively sparse standing hairs mixed with sparse short hairs over the surface; length of the longest pronotal hair 0.10-0.13 mm. Head, waist, gaster, mandible, antenna and legs yellow or pale brown: mesosoma brown.

Type Material

Holotype worker from Sa Pa. Lao Cai, N. Vietnam. 4 V 2002, K. Eguchi leg., Eg02-VN-272. Seven paratype workers, same data as holotype.

Holotype and two paratypes arc deposited in Entomological Collection of the Institute of Ecology and Biological Resources; some paratypes are in SKY Collection and Natural History Museum of the National Science Museum.

Etymology

The specific epithet is dedicated to Dr. Tuan Viet Bui of the Institute of Ecology and Biological Resources, Vietnam.

References

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).
Jaitrong, W., Yamane, S. and Wiwatwitaya, D. 2010. The Army Ant Aenictus wroughtonii and related species in the Oriental region, with descriptions of two new species. Japanese Journal of Systematic Entomology. 16:33-36. PDF
Jaitrong, W. and Yamane, S. 2011. Synopsis of Aenictus species groups and revision of the A. currax and A. laeviceps groups in the eastern Oriental, Indo-Australian, and Australasian regions (Hymenoptera: Formicidae: Aenictinae). Zootaxa. 3128:1–46. PDF

References based on Global Ant Biodiversity Informatics

Borowiec M. L. 2016. Generic revision of the ant subfamily Dorylinae (Hymenoptera, Formicidae). ZooKeys 608: 1–280.
Eguchi K., B. T. Viet, and S. Yamane. 2014. Generic Synopsis of the Formicidae of Vietnam (Insecta: Hymenoptera), Part IICerapachyinae, Aenictinae, Dorylinae, Leptanillinae, Amblyoponinae, Ponerinae, Ectatomminae and Proceratiinae. Zootaxa 3860: 001-046.
Guénard B., and R. R. Dunn. 2012. A checklist of the ants of China. Zootaxa 3558: 1-77.
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.; Yamane, S.; Wiwatwitaya, D. 2010. The army ant Aenictus wroughtonii (Hymenoptera, Formicidae, Aenictinae) and related species in the Oriental region, with descriptions of two new species. Japanese Journal of Systematic Entomology 16:33-46.