Aenictus fuchuanensis

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Aenictus fuchuanensis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Aenictus
Species: A. fuchuanensis
Binomial name
Aenictus fuchuanensis
Zhou, 2001

The species was collected in an experimental tree plantation (see Bruelheide et al. 2014) that was planted four years prior and at the time of collection still had an open character with a maximum tree height of 3 m and abundant patches of bare soil. Hence, A. fuchuanensis may be able to inhabit more open landscapes and not be restricted to forests, which may explain the relatively wide distribution of the species, which occurs from south Thailand to south-east China. (Staab 2015)

Identification

A member of the ceylonicus group. Jaitrong and Yamane (2013) – Aenictus fuchuanensis is similar to Aenictus maneerati, Aenictus pinkaewi, and Aenictus sundalandensis in having the long cylindrical petiole and the short head (CI 100-112). It is most similar to A. pinkaewi but the sculpturing on the mesosoma is weaker than in the latter (anterior portion of pronotum densely punctate, lateral face of pronotum finely reticulate in the former, while promesonotum entirely punctate in the latter).

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Oriental Region: Cambodia, Laos, Thailand, Vietnam.
Palaearctic Region: China (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 fuchuanensis. 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.

  • fuchuanensis. Aenictus fuchuanensis Zhou, 2001b: 59, 231, figs. 74, 75 (w.) CHINA.

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 3.5, HL 0.66, HW 0.72, CI 109, SL 0.56, SI 77, PW 0.40, AL 1.10. Paratypes: TL 3.2~3.5, HL 0.62~0.66, HW 0.68~0.72, CI 104~109, SL 0.53~0.56, SI 77~80, PW 0.36~0.40, AL 1.08~1.10.

Head slightly broader than long, sides and occipital border convex. Mandible narrow, with a large apical tooth and 3 small teeth. There remains a gap between posterior borders of mandibles and center of anterior clypeal border 2 X as wide as maximum width of mandible. Clypeus narrow, anterior border straight, without any tooth. Frontal lobes narrowly apart. Antennal scapes nearly reaching occipital border of head. Pronotum convex above, promesonotal suture vestigial, mesopropodeal suture incised; basal face of propodeum straight, declivity concave, conjunction between them acutely angular, with low transverse ridge. Petiolar node convex dorsally, elevate posteriorly; Subpetiolar process low and indistinct. Gaster longitudinally oval. Sting developed. Mandibles with fine longitudinal striations; head smooth and shining; alitrunk, petiole and post petiole with coarse reticulations; mesopleura and dorsal of propodeum with several longitudinal striations; gaster smooth and shining. Erect and suberect hairs abundant.

Color reddish brown, alitrunk, petiole and postpetiole darker.

Jaitrong and Yamane (2013) - (n = 10). TL 3.10–3.45 mm; HL 0.63–0.70 mm; HW 0.70–0.75 mm; SL 0.53–0.58 mm; ML 0.98–1.05 mm; PL 0.25–0.28 mm CI 107– 112; SI 75–79.

Head in full-face view slightly shorter than broad, anterior portion slightly broader than posterior portion, sides convex and posterior margin almost straight; occipital margin bearing a carina. Antennal scape relatively long, reaching 2/3 of head length. Frontal carina short, slightly extending beyond the level of posterior margin of torulus. Masticatory margin of mandible with 4 teeth, including a large apical tooth; basal margin feebly concave. Maximum width of gap between anterior clypeal margin and mandibles about 2 times as broad as maximum width of mandible. Promesonotum strongly convex dorsally and sloping gradually to metanotal groove that is indistinct; metapleural gland bulla relatively small, its maximum diameter about 2 times as long as distance between propodeal spiracle and metapleural gland bulla. Propodeum in profile with almost straight dorsal outline; propodeal junction acutely angulated; declivity of propodeum broad, shallowly concave, and encircled with a distinct rim. Petiole cylindrical, distinctly longer than high, with its dorsal outline slightly elevated posteriorly, posterior face of petiole flat, and encircled with a indistinct carina; subpetiolar process generally weakly developed, seen in profile its ventral outline almost straight or weakly convex, and anteroventral corner acutely angulated. Postpetiole almost as long as petiole, with its dorsal outline elevated posteriorly.

Head entirely smooth and shiny. Mandible with fine longitudinal striation. Basal half of antennal scape microreticulate; apical half smooth and shiny. Promesonotum reticulate except anteriormost portion punctate; mesopleuron, metapleuron and propodeum punctuate; in addition mesopleuron and metapleuron with approximately 10 longitudinal rugae. Petiole and postpetiole densely punctate. Femora entirely smooth and shiny except punctate basal portion; tibiae entirely smooth and shiny.

Head and mesosoma dorsally with relatively dense standing hairs; longest pronotal hair 0.23–0.25 mm long. Head and mesosoma dark reddish brown; petiole, postpetiole and antenna reddish brown; gaster and legs yellowish brown, paler than head, mesosoma and waist; mandible dark brown.

Type Material

Jaitrong and Yamane (2013) - CHINA: Holotype and 19 paratype workers from Fuchaun County, Guangxi, 18.VI.1998, Shanyi Zhou leg (not examined).

References