Aenictus jawadwipa

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

The type series of this species was collected from highland (ca. 1,300m alt., W. Java) by a stream in a primary forest. The non-type colonies from Borneo were all collected from lowland primary forests (200-700m alt.). This species was active both day and night.

Identification

A member of the ceylonicus group. Aenictus jawadwipa is most similar in general appearance to Aenictus eguchii. (Jaitrong and Yamane 2013)

Keys including this Species

• Key to southeastern Asian Aenictus ceylonicus group species

Distribution

Borneo (Sabah and Sarawak) and W. Java

Distribution based on Regional Taxon Lists

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

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 jawadwipa. 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.

• jawadwipa. Aenictus jawadwipa Jaitrong & Yamane, 2013: 193, fig. 23A-C (w.) INDONESIA (Java).
  • Type-material: holotype worker, 43 paratype workers.
  • Type-locality: holotype Indonesia: Java, Cibodas Botanical Garden, 29.xi.2009, WJT09-ID-16 (W. Jaitrong); paratypes with same data.
  • Type-depositories: MZBJ (holotype); BMNH, MCZC, MZBJ, SKYC, TNHM (paratypes).
  • Distribution: Indonesia (Java), Malaysia (Sabah, Sarawak).

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 paratype workers, n = 10): TL 2.40–2.90 mm; HL 0.53–0.58 mm; HW 0.48–0.53 mm; SL 0.40–0.45 mm; ML 0.78–0.88 mm; PL 0.20–0.23 mm; CI 90–91; SI 84–86.

Head in full-face view slightly longer than broad, sides convex, posterior margin weakly convex; occipital margin bearing a carina. Antennal scape relatively short, reaching 2/3 of head length. Frontal carina relatively long, slightly extending beyond the level of posterior margin of torulus. Parafrontal ridge feeble and incomplete. Anterior clypeal margin feebly concave. Masticatory margin of mandible with large acute apical tooth followed by a medium-sized subapical tooth, and 4 denticles; basal margin almost straight. Maximum width of gap between anterior clypeal margin and mandibles about 1.9 times as broad as maximum width of mandible. Promesonotum strongly convex dorsally and sloping gradually to metanotal groove; mesopleuron relatively long, not clearly demarcated from metapleuron; metapleural gland bulla relatively small, its maximum diameter about 1.6 times as long as distance between propodeal spiracle and metapleural gland bulla. Propodeum in profile relatively long, with straight dorsal outline; propodeal junction acutely angulated, overhanging the declivitous face of propodeum; the declivity widely and shallowly concave, encircled with a distinct rim. Petiole almost as long as high, seen in profile its node short and dorsal outline convex; subpetiolar process developed, with anteroventral and posteroventral corners angulated, margin connecting anterior and posterior corners strongly concave. Postpetiole slightly smaller than petiole, with its dorsal outline convex.

Head and gaster entirely smooth and shiny. Mandible very finely striate. Basal portion of antennal scape microreticulate, 2/3 apical smooth and shiny. Pronotum entirely smooth and shiny except for anteriormost portion densely punctate; mesopleuron, metapleuron, propodeum, and petiole reticulate; in addition mesopleuron and metapleuron with 3-4 longitudinal or irregular rugae; anterior, lateral and posterior faces of postpetiole reticulate, but its dorsum smooth and shiny.

Head and mesosoma dorsally with relatively dense standing hairs mixed with decumbent hairs; longest pronotal hair 0.25–0.28 mm long. Head, petiole, gaster, and legs yellowish brown; mesosoma reddish brown.

Type Material

Holotype. INDONESIA: Worker from W. Java, Cibodas Botanical Garden, 29.XI.2009, leg. W. Jaitrong, WJT09-ID16 (MZB). Paratypes. Forty-three workers, same data as holotype (BMHN, MCZC, MZB, SKYC, THNHM).

Etymology

The specific name is after the type locality, Java Island (in Sanscrit).

References

• Antony, A.K., Prasad, G. 2022. Two new species of army ants of the Aenictus ceylonicus group (Hymenoptera: Formicidae) from Kerala, India. Journal of Threatened Taxa 14(3): 20780-20785 (doi:10.11609/jott.6962.14.3.20780-20785).
• 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.
• Yamane, S., Tanaka, H.O., Hasimoto, Y., Ohashi, M., Meleng, P., Itioka, T. 2021. A list of ants from Lambir Hills National Park and its vicinity, with their biological information: Part II. Subfamilies Leptanillinae, Proceratiinae, Amblyoponinae, Ponerinae, Dorylinae, Dolichoderinae, Ectatomminae and Formicinae. Contributions from the Biological Laboratory, Kyoto University 31, 87–157.

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.