Aenictus baliensis

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

Known only from the type locality near a lowland secondary forest.

Identification

A member of the ceylonicus group. Jaitrong and Yamane (2013) - Aenictus baliensis is similar to Aenictus longicephalus, Aenictus minipetiolus and Aenictus wiwatwitayai in having a mandible with more than 4 teeth and smooth and shiny propodeum. It is most similar in general appearance to A. minipetiolus, but can be separated from the latter by the straight basal margin of the mandibles (distal 2/3 of basal margin of mandible straight, proximal 1/3 sloping gradually to the base of mandible in the latter), pronotum with dense standing hairs (a few hairs, less than 10 in the latter), and body size being smaller than in the latter (TL 2.10-2.70 mm, HW 0.38-0.48 mm in A. baliensis; TL 2.70-3.10 mm, HW 0.54-0.65 mm in A. minipetiolus).

Keys including this Species

Key to southeastern Asian Aenictus ceylonicus group species

Distribution

Bali

Distribution based on Regional Taxon Lists

Indo-Australian Region: Indonesia (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 baliensis. 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.

baliensis. Aenictus baliensis Jaitrong & Yamane, 2013: 174, fig. 2A-C (w.) INDONESIA (Bali).
- Type-material: holotype worker, 6 paratype workers.
- Type-locality: holotype: Indonesia: Bali, Ubud, Aji Lodge, 23.iv.1998, Eg98-BALI-650 (K. Eguchi); paratypes with same data.
- Type-depositories: MZBJ (holotype); SKYC, TNHM (paratypes).
- Distribution: Indonesia (Bali).

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 = 7). TL 2.10-2.70 mm; HL 0.50-0.55 mm; HW 0.38-0.48 mm; SL 0.30-0.40 mm; ML 0.68-0.80 mm; PL 0.18 0.20 mm; CI 75-86; SI 79-86.

Head in full-face view subrectangular, clearly longer than broad, sides weakly convex, posterior margin straight; occipital margin bearing a distinct carina. Antennal scape relatively short, not reaching 2/3 of head length. Frontal carina relatively long, slightly extending beyond the level of posterior margin of torulus. Parafrontal ridge absent. Anterior clypeal margin concave, concealed by curved anterior extension of frontal carina. Masticatory margin of mandible with large acute apical tooth followed by a medium-sized subapical tooth, 4 denticles, and a medium-sized basal tooth; basal margin almost straight. Maximum width of gap between anterior clypeal margin and mandibles about 1.8 times as broad as maximum width of mandible. Promesonotum weakly convex dorsally and sloping gradually to metanotal groove; mesopleuron relatively long, demarcated from metapleuron by indistinct groove; metapleural gland bulla relatively large, its maximum diameter about 2.4 times as long as distance between propodeal spiracle and metapleural gland bulla. Propodeum in profile with feebly convex dorsal outline; propodeal junction angulate, nearly right-angled; declivity of propodeum widely and shallowly concave, encircled with a rim. Petiole slightly longer than high, with its dorsal outline convex; subpetiolar process low and subrectangular. Postpetiole shorter than petiole, with its dorsal outline roundly convex.

Head including mandible and antennal scape entirely smooth and shiny. Promesonotum smooth and shiny except for anteriormost portion punctate; propodeal dorsum and metapleuron smooth and shiny; mesopleuron and lateral face of propodeum shagreened; petiole entirely smooth and shiny except for lateral face superficially reticulate; postpetiole smooth and shiny.

Head and mesosoma dorsally with relatively dense standing hairs; longest pronotal hair 0.15–0.18 mm long. Head, petiole, gaster, and legs yellowish brown; mesosoma reddish brown.

Type Material

Holotype. INDONESIA: Worker from Bali, Ubud, Aji Lodge, 23.IV.1998, leg. K. Eguchi, Eg98-BALI-650 (MZB). Paratypes. Six workers, same data as holotype (SKYC, THNHM) and seventeen workers from Indonesia, Bali, Ubud, Aji Lodge, 23-24.IV.1998, leg. Sk Yamane (SKYC, THNHM).

Etymology

The specific name is after the type locality, Bali Island of Indonesia.

References

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., and S. Yamane. 2013. The Aenictus ceylonicus species group (Hymenoptera, Formicidae, Aenictinae) from Southeast Asia. Journal of Hymenoptera Research 31: 165-233.