Aenictus lifuiae

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Aenictus lifuiae
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Aenictus
Species: A. lifuiae
Binomial name
Aenictus lifuiae
Terayama, 1984

Aenictus lifuiae side (www.niaes.affrc.go.jp).jpg

Aenictus lifuiae top (www.niaes.affrc.go.jp).jpg

Specimen labels

Terayama (1984) reported that the material from Meishan Cun was taken “at hard clay soil of the road cutting about 50 cm above ground level”. When another person saw it at 5 p.m., the colony was prepared for the nuptial flight. One male was in the nest entrance, and about 40 workers were seen coming out of the nest, gathering around the entrance in a circle (Jaitrong & Yamane, 2013).

Identification

A member of the ceylonicus group. Jaitrong and Yamane (2013) - Smaller specimens of A. lifuiae collected from Iriomote-jima and Okinawa-jima, southern Japan, have a mandible that is almost linear, an anterior clypeal margin that is straight or weakly concave, and a gap between between the mandibles and anterior clypeal margin. These characteristics are used to separate the A. ceylonicus group from the other groups of the genus Aenictus.

Aenictus lifuiae, though variable in size and associated morphological characters, is easily distinguished from the other members of the group as follows: masticatory margin of mandible with large acute apical tooth followed by a series of 6–7 denticles of two sizes, the larger alternating with 1–2 smaller (almost same size as in the other members of the group); a gap between anterior clypeal margin and mandibles rather small or indistinct, maximum width shorter than 1 time as wide as maximum width of mandible (large and distinct in the others).

Three specimens collected from Okinawa-jima, Japan are slightly larger than the type series from Taiwan (HW 0.48–0.53 mm in the type series; 0.55–0.58 mm in Okinawan specimens).

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Oriental Region: Taiwan (type locality).
Palaearctic Region: China, Japan.

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 lifuiae. 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

Unusual for the genus in that workers and males are known for this species.

Worker

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • lifuiae. Aenictus lifuiae Terayama, 1984: 13, figs. 1-13 (w.m.) TAIWAN.

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

Description

Worker

Jaitrong and Yamane (2013) - (holotype and paratypes, n = 10). TL 2.55–2.80 mm; HL 0.53–0.58 mm; HW 0.48–0.53 mm; SL 0.39–0.45 mm; ML 0.75–0.88 mm; PL 0.18–0.23 mm CI 90–91; SI 82–86.

Non-type workers (larger): TL 2.80–2.85 mm; HL 0.55–0.58 mm; HW 0.50–0.53 mm; SL 0.40–0.41 mm; ML 0.83–0.88 mm; PL 0.20–0.23 mm CI 91–95; SI 76–80.

Non-type workers (smaller): TL 2.10–2.20 mm; HL 0.48–0.50 mm; HW 0.40–0.43 mm; SL 0.23–0.25 mm; ML 0.63–0.68 mm; PL 0.15–0.18 mm CI 84–85; SI 56–59.

(holotype and paratypes). Head in full-face view subrectangular, distinctly longer than broad, with sides slightly convex and posterior margin almost straight. Antennal scape extending beyond midlength of head, but not reaching 2/3 of head length; antennal segment II almost as long as III and each longer than broad; IV-VIII each slightly broader than long; terminal segment about 2 times as long as broad. Frontal carina short, slightly extending beyond the level of posterior margin of torulus. Masticatory margin of mandible with a large apical tooth, followed by 6 teeth of two sizes, a larger alternating with a smaller; basal margin lacking denticles. In smaller workers maximum width of gap between anterior clypeal margin and mandibles about 0.9–1.0 times as broad as maximum width of mandible (larger workers almost lacking the gap). Promesonotum in profile strongly convex dorsally and sloping gradually to metanotal groove; metanotal groove rather distinct but shallow; mesopleuron clearly demarcated from metapleuron by a shallow groove; metapleural gland bulla relatively large and transparent, its maximum diameter about 3.0–3.5 times as long as distance between propodeal spiracle and metapleural gland bulla. Propodeum in profile with weakly convex to almost straight dorsal outline; propodeal junction angulated; declivity of propodeum narrowly and shallowly concave, encircled with a distinct rim. Petiole excluding subpetiolar process almost as long as high, with its dorsal outline convex; subpetiolar process weakly developed, with its ventral outline convex. Postpetiole clearly shorter than petiole, its dorsal outline convex.

Head and gaster entirely smooth and shiny. Mandible very finely striate. Antennal scape entirely superficially microreticulate, but shiny. Promesonotum entirely smooth and shiny except for reticulate anteriormost portion; mesopleuron, metapleuron, lateral face of propodeum reticulate; dorsal face of propodeum punctate, somewhat shiny; petiole with reticulate lateral face and smooth and shiny dorsal face; postpetiole same as petiole. Legs smooth and shiny.

Head and mesosoma dorsally with relatively dense standing hairs; longest pronotal hair 0.13–0.15 mm long. Head, petiole, postpetiole, gaster, and legs yellowish brown; mesosoma reddish brown.

Type Material

Jaitrong and Yamane (2013) - Holotype (NAIST), 152 paratype workers (NAIST, TARI) and 1 paratype male (NAIST) from Taiwan, Kaoshiung Hsien, Taoyuan Xiang, Meishan Cun (ca. 800 m alt.). Holotype and nine paratype workers were examined.

References