Aenictus hottai

Aenictus hottai
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Dorylinae
Genus:	Aenictus
Species:	A. hottai
Binomial name
Aenictus hottai Terayama & Yamane, 1989 Specimen Labels

Aenictus hottai, together with its close relative Aenictus yamanei, are the only known members of the A. hottai species group. Both are probably restricted to Sundaland (south-east Asia) and inhabit lowland primary rainforests.

Identification

A member of the hottai species group.

Wiwatwitaya and Jaitrong (2011) - A. hottai is very similar to Aenictus yamanei in general appearance as they share the dense punctation on the head and mesosoma, the peculiar subpetiolar process and the superficially reticulate first gastral segment. However, A. hottai is separated from A. yamanei by the following conditions: body much larger (HW 0.93-1.00 mm, ML 1.63-1.75 mm in A. hottai; HW 0.63-0.70 mm; ML 1.22-1.27 mm in A. yamanei), head relatively shorter (CI 88-91 vs 79-85), posterior face of petiole feebly convex and wrinkled and not marginated with a rim (shallowly concave without longitudinal wrinkles and marginated with a very thin rim in A. yamanei).

• Larger species (HW 0.93-1.00 mm; ML 1.63-1.75 mm); head relatively shorter (CI 88-91) . . . . . Aenictus hottai

• Smaller species (HW 0.63-0.70 mm; ML 1.22-1.27 mm); head relatively longer (CI 79-85) . . . . . Aenictus yamanei

Key to Aenictus species groups

Distribution

Malay Peninsula (southern Thailand and Malaysia), Borneo (Sarawak), Sumatra.

Latitudinal Distribution Pattern

Latitudinal Range: 4.333333333° to 4.333333333°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

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

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

Wiwatwitaya and Jaitrong (2011) - According to the specimen examined, all colonies of A. hottai were collected from the forest floor in the lowland primary forest. Rościszewski & Mashchwitz (1994), Malsch et al. (2003) also observed this species in a lowland primary forest in Pasoh, Malay Peninsula. This species is probably a Sundaland species; so far northern limit of its range in latitude is the Thai- Malay border (ca. 7˚N) near the Kangar-Pattani line (see Woodruff 2003). Rościszewski & Mashchwitz (1994) reported that in the Pasoh Forest Reserve A. hottai preyed on ants of the ponerine genus Odontomachus.

Explore Overview of Aenictus biology  Little is known about the biology of Aenictus hottai. 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.

• hottai. Aenictus hottai Terayama & Yamane, 1989: 598, figs. 1, 2 (w.) INDONESIA (Sumatra).
  • Type-material: holotype worker, 9 paratype workers.
  • Type-locality: holotype Indonesia: Sumatra, Ulu Gadut, nr Padang, 27-30.viii.1985 (Sk. Yamane); paratypes with same data.
  • Type-depositories: BZBC (holotype); BZBC, KUIC (paratypes).
  • Status as species: Bolton, 1995b: 59; Jaitrong & Nabhitabhata, 2005: 11; Wiwatwitaya & Jaitrong, 2011: 559 (redescription); Khachonpisitsak, et al. 2020: 28.
  • Distribution: Indonesia (Sumatra), Malaysia (Peninsula, Sarawak), Thailand.

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

Description

Worker

Wiwatwitaya and Jaitrong (2011) - (n = 10 including two paratypes): TL 4.65-5.00 mm; HL 1.05-1.13 mm; HW 0.93-1.00 mm; SL 0.93-1.00 mm; ML 1.63-1.75 mm; PL 0.40-0.43 mm; CI 88-91; SI 93-100.

(paratypes and non-type specimens). Head in full-face view slightly longer than broad, with sides convex and posterior margin almost straight. Antennal scape almost reaching posterolateral corner of head. Frontal carina not reaching midlength of head, well developed anteriorly and poorly developed posteriorly; parafrontal ridge extending posterior less than 1/3 of head length; seen in profile its anterior part raised high and subtriangular, and poorly developed posteriorly. Mandible broad and triangular, its masticatory margin with a large apical tooth followed by a small subapical tooth and a series of 16-17 minute denticles of uniform size; basal margin of mandible lacking denticles. Mososoma stout; anepisternum clearly demarcated from katepisternum. Propodeum in profile with almost striaght dorsal outline; propodeal junction acutely angulate; opening of propodeal spiracle clearly circular with its diameter about 2.4 times as long as diameter of postpetiolar spiracle. Petiole round and almost as long as high; posterior slope of petiole seen in profile feebly convex, seen from above with blunt lateral carinae but not margined basally by a carina; subpetiolar process large with anterior corner rounded, posteroventrally produced into an arm with a blunt tip; margin connecting anterior corner and the tip of the arm clearly concave. Postpetiole slightly longer than petiole, its dorsal outline slightly elevated posteriorly.

Head, mesosoma, petiole, postpetiole, and legs densely punctate and opaque; mandible densely punctate extensively, finely striate along basal margin, and smooth and shiny along masticatory margin and at apex; antennal scape micropunctate. Proprodeal dorsum with several short longitudinal ridges in front of junction. Posterior face of petiole wrinkled. Gaster with weaker sculpturation than head, finely and superficially reticulate, subopaque and slightly shining.

Head with a pair of long standing hairs mixed with relatively sparse short hairs over the surface; mesosoma with relatively sparse long standing hairs mixed with sparse short hairs over the surface; length of the longest pronotal hair 0.50-0.53 mm. Entire Body dark reddish-brown.

Type Material

Wiwatwitaya and Jaitrong (2011) - The holotype and 9 paratype workers (Bogor Zoological Museum and SKY Collection) from Ulu Gadut nr Padang, W. Sumatra, Indonesia, 27-30 VIII 1985 (two paratypes were examined, SKYC).

References

• Gomez, K. 2022. A revision of the Afrotropical species of the Dorylinae ant genus Aenictus (Hymenoptera: Formicidae) based on the worker caste. Belgian Journal of Entomology 124: 1–86 (doi:10.5281/zenodo.5898821).
• 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).
• Sahoo, B., Ramakrishnaiah, S., Rajan, P.D., Datta-Roy, A. 2023. A new species of army ant genus Aenictus (Hymenoptera: Formicidae) from India. Journal of the Entomological Research Society 25(3), 615-622 (doi:10.51963/jers.v25i3.2504).
• Terayama, M. & S. Yamane. 1989. The ant genus Aenictus (Hymenoptera, Formicidae) from Sumatra, with descriptions of three new species. Japanese Journal of Entomology, 57, 597-603. (page 598, figs. 1, 2 worker described)
• Wiwatwitaya, D. and Jaitrong, W. 2011. The army ant Aenictus hottai (Hymenoptera: Formicidae: Aenictinae) and related species in Southeast Asia, with a description of a new species. Sociobiology. 58:557-565.
• 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. 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.; Nabhitabhata, J. 2005. A list of known ant species of Thailand. The Thailand Natural History Museum Journal 1(1): 9-54.
• Malsch A. K. F., K. Rosciszewski, and U. Maschwitz. 2003. The ant species richness and diversity of a primary lowland rain forest, the Pasoh Forest reserve, West Malaysia. in T. Okuda, N. Manokaran, Y. Matsumoto, K. Niiyama, S. C. Thomas, and P. S. Ashton, eds. Pasoh: Ecology and Natural History of a Southeast Asin Lowland Tropical Rain Forest, pp 347-374.
• Matsumoto T., T. Itioka, S. Yamane, and K. Momose. 2009. Traditional land use associated with swidden agriculture chnages encounter rates of the top predator, the army ant, in Southern Asian tropical rain forests. Biodivers. Conserv. 18: 3139-3151.
• Terayama M.; Yamane, S. 1989. The army ant genus Aenictus (Hymenoptera, Formicidae) from Sumatra, with descriptions of three new species. Japanese Journal of Entomology 57:597-603.
• Wiwatwitaya D.; Jaitrong, W. 2011. The army ant Aenictus hottai (Hymenoptera: Formicidae: Aenictinae) and related species in Southeast Asia, with a description of a new species. Sociobiology 58:557-565.
• Yamane S.; Nona, A. R. 1994. Ants from Lambir Hills National Park, Sarawak. Pp. 222-226 in: Inoue, T.; Hamid, A. A. (eds.) 1994. Plant reproductive systems and animal seasonal dynamics. Long-term study of dipterocarp forests in Sarawak. Kyoto: Center for Ecological Research, Kyoto University, vii + 255 pp.