Aenictus duengkaei

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Aenictus duengkaei
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Aenictus
Species: A. duengkaei
Binomial name
Aenictus duengkaei
Jaitrong & Yamane, 2012

Aenictus duengkaei casent0903678 p 1 high.jpg

Aenictus duengkaei casent0903678 d 1 high.jpg

Specimen Labels

This species has been known only from eastern Thailand. The type series was collected from soil in a lowland dry evergreen forest (ca. 200 m), while the other colony (WJT04-E50) was collected from soil in an agricultural area. Thus, this species inhabits both primary and disturbed forests. (Jaitrong & Yamane 2012)

Identification

A member of the javanus species group. Aenictus duengkaei is similar to Aenictus piercei in terms of body size and coloration. Furthermore, the propodeal declivity is not margined basally with a carina in both species. However, A. duengkaei is easily separated from the latter by the condition of the mandible that has a distinct denticle on the basal margin, while the denticle is lacking in A. piercei. (Jaitrong & Yamane 2012)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Oriental Region: Thailand (type locality).


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Little is known about the biology of Aenictus duengkaei. 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 New General Catalogue, a catalogue of the world's ants.

  • duengkaei. Aenictus duengkaei Jaitrong & Yamane, 2012: 55, figs. 2, 7A (w.) THAILAND.

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

Description

Worker

Holotype: TL 1.90 mm; HL 0.43 mm; HW 0.38 mm; SL 0.20 mm; ML 0.58 mm; PL 0.15 mm; CI 88; SI 53.

Larger workers (paratypes, n = 5): TL 1.80-1.90 mm; HL 0.43-0.45 mm; HW 0.36-0.38 mm; SL 0.19-0.20 mm; ML 0.53-0.58 mm; PL 0.14-0.15 mm; CI 83-88; SI 52-53. Smaller workers (paratypes, n = 3): TL 1.50-1.55 mm; HL 0.40-0.43 mm; HW 0.25-0.28 mm; SL 0.15-0.16 mm; ML 0.45-0.48 mm; PL 0.10-0.13 mm; CI 63-65; SI 59-60.

Head in full-face view distinctly longer than broad and subrectangular, with sides weakly convex or almost parallel, and posterior margin clearly concave; seen in profile occipital corner of head rounded. Antennal scape very short, not reaching midlength of head; antennal segment II clearly longer than each of III-VI; III-VI shorter than broad; terminal segment longer than VII+VIII+IX and about 1.6 times as long as broad. Anterior margin of clypeus bearing 5-7 denticles. Masticatory margin of mandible with 3 acute teeth including a large apical tooth; basal margin with 1-2 denticles behind large basal tooth. Mesosoma seen in profile almost flat dorsally; propodeal junction angulate; declivity of propodeum almost flat, with blunt lateral carinae, but not demarcated basally by a transverse carina. Petiole round almost as long as high; subpetiolar process well developed, subrectangular, its ventral border almost straight and longer than posterior border; postpetiole slightly smaller than petiole and its dorsal outline roundly convex.

Head and antennal scape smooth and shiny; mandible extensively smooth but narrow zone along basal margin sculptured. Dorsal and lateral face of pronotum smooth and shiny except for anteriormost portion microreticulate; mesonotum smooth and shiny; mesopleuron superficially shagreened with smooth and shiny interspaces; metapleuron and propodeum shiny but microreticulate. Petiole entirely microreticulate but its dorsal face with a small area that is smooth (in larger specimens this area weakly sculptured). Postpetiolar node almost smooth and shiny.

Head with relatively sparse standing hairs; mesosoma dorsally with relatively dense standing hairs mixed with sparse short hairs over the surface; longest pronotal hairs 0.07-0.10 mm long. Head, gaster and legs yellowish brown; mesosoma, petiole and postpetiole reddish brown; mandible darker than elsewhere.

Type Material

Holotype worker from E. Thailand, Chacheongsao Prov., Khao Ang Reu Nai, dry evergreen forest, 22.VIII.2003, Sk. Yamane leg., TH03-SKY-79 (Natural History Museum of the National Science Museum). Twelve paratype workers, same data as holotype (The Natural History Museum, Museum of Comparative Zoology, SKY Collection, Natural History Museum of the National Science Museum).

Etymology

The specific name is dedicated to Dr. Prateep Duengkae of the Faculty of Forestry, Kasetsart University, who helped us in collecting material in eastern Thailand.

References

  • Jaitrong, W. & Yamane, S. (2012) Review of the Southeast Asian species of the Aenictus javanus and Aenictus philippinensis species groups (Hymenoptera, Formicidae, Aenictinae). ZooKeys 193: 49–78, doi: 10.3897/zookeys.193.2768.