Aenictus hodgsoni

A. hodgsoni is dominant in continental Southeast Asia, distributed from lowland to highland in varied forest types (hill evergreen forest, dry evergreen forest, evergreen rainforest, mixed deciduous forest, and savanna). This species is active both day and night. We found it preying on other ant species such as Anoplolepis gracilipes (Thailand), Camponotus rufoglaucus (Thailand), Camponotus sp. (Vietnam), Iridomyrmex anceps (Thailand), Technomyrmex sp. (bicolor group) (Vietnam), and also on cockroaches (Thailand). (Jaitrong and Yamane 2011)

Identification
Jaitrong and Yamane (2011) - A member of the laeviceps species group. This species was removed from synonymy with the closely related Aenictus fergusoni based on the following characteristics: propodeum partly smooth and shiny in A. hodgsoni (entirely punctate in A. fergusoni); propodeum in profile almost straight dorsally in A. hodgsoni (slightly convex in A. fergusoni); declivity of propodeum above without transverse carina in A. hodgsoni (with a distinct transverse carina in A. fergusoni). Aenictus brevinodus and Aenictus bodongjaya are also very similar to this species in having sparse standing hairs mixed with sparse short hairs on the head and promesonotum, and the mesopleuron being entirely densely sculptured. A. hodgsoni can be distinguished from A. bodongjaya by the femora being extensively superficially reticulate and shiny, the tibiae very finely reticulate (legs entirely smooth and shiny in A. bodongjaya), and it can be separated from A. brevinodus by having the petiole slightly longer than high (clearly shorter than high in A. brevinodus).

Key to Aenictus species groups / Key to Aenictus laeviceps group species

Distribution
South China, Hong Kong, Vietnam, Laos, Cambodia, Myanmar, Thailand, Malay Peninsula (S. Thailand), Java (Indonesia), Bali (Indonesia), and Lombok (Indonesia).

Distribution based on Regional Taxon Lists
Indo-Australian Region: Indonesia. Oriental Region: Cambodia, Laos, Myanmar, Thailand, Vietnam. Palaearctic Region: China.

Biology
Staab (2014) observed workers tending Hemiptera (Eutrichosiphum heterotrichum) on fresh shoots of the plant (Lithocarpus glaber) in in Xingangshan, Jiangxi Prov., China. The ants were seen imbibing honeydew droplets extruded by the aphids and "the ants had a well-established foraging trail, with many foragers going back and forth between the site of the trophobiosis and a hole in the soil about 2 m away. The ants defended their mutualistic partners aggressively by stinging and biting the incautious observer." The interactions persisted for hours but was not found again when the site was checked one day later.

Castes
Known only from the worker caste.

Nomenclature

 *  hodgsoni. Aenictus fergusoni var. hodgsoni Forel, 1901a: 474 (w.) MYANMAR. Junior synonym of fergusoni: Wilson, 1964a: 462. Revived from synonymy and raised to species: Jaitrong, et al. 2011: 321. See also: Jaitrong & Yamane, 2011: 35.

Jaitrong and Yamane (2011) - The specimens collected from Vietnam, Laos, Cambodia, and Thailand agree well with the type series from Myanmar, but in the single colony from Lombok, Indonesia, the workers have smooth and shiny femora, and the petiole is slightly smaller than in the type series. In the single colony from Bali, Indonesia, the workers have a reticulated petiole (entirely smooth and shiny in the type series). All Thai and Vietnamese specimens cited as A. fergusoni in Yamane et al. (2003), and Eguchi et al. (2005), and Jaitrong and Nabhitabhata (2005) were reidentified as A. hodgsoni in the present study. Aenictus laeviceps recorded from Vietnam by Radchenko (1993) is possibly A. hodgsoni (cf. Yamane et al. 2003).

Worker
Jaitrong and Yamane (2011) - Measurements. Worker lectotype and paralectotypes (n = 6): TL 3.50–3.70 mm; HL 0.75–0.78 mm; HW 0.63–0.68 mm; SL 0.60–0.65 mm; ML 1.05–1.13 mm; PL 0.23–0.25 mm; CI 83–87; SI 96–100.

Lectotype and paralectotypes. Head in full-face view slightly longer than broad, with its sides slightly convex and posterior margin almost straight; occipital margin bearing a narrow carina. Antennal scape relatively short, not reaching posterolateral corner of head; antennal segments II–X each longer than broad; II almost as long as each of III–VI. Frontal carina short, not extending beyond the level of posterior margin of torulus. Anterior margin of clypeus bearing several denticles. Masticatory margin of mandible with a large apical tooth followed by a medium-sized subapical tooth, 4–5 denticles, and a medium-sized basal tooth; basal margin lacking denticles. Promesonotum in profile convex dorsally; propodeum in profile with its dorsal outline almost straight; propodeal junction angulate, right-angled; area behind propodeal spiracle and above metapleural gland bulla impressed; declivity not distinctly margined dorsally and laterally, seen from back tapering above. Petiole almost as long as high, in profile its dorsal outline strongly convex; subpetiolar process well developed and triangular, its apex directed downward and backward; postpetiole almost as long as petiole. Head entirely smooth and shiny. Mandible very finely striate except along masticatory margin. Antennal scape entirely microrecticulate. Pronotum smooth and shiny, its anteriormost portion punctate; mesothorax, metapleuron and lateral face of propodeum with dense punctures and several longitudinal rugae; dorsal face of propodeum essentially smooth and shiny. Petiole entirely smooth and shiny except for anteriormost portion punctate; postpetiole entirely smooth and shiny. Femora extensively superficially reticulate and shiny; tibiae very finely reticulate. Head and mesosoma dorsally with relatively sparse standing hairs mixed with sparse short hairs over the surface; longest pronotal hairs 0.30–0.33 mm long. Entire body dark reddish brown. Typhlatta spot located anterior to occipital corner.

Type Material
Aenictus fergusoni var. hodgsoni: Lectotype and five paralectotype workers from Burma [Myanmar], Moulmain (, examined).