Leptomyrmex flavitarsus

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Leptomyrmex flavitarsus
Leptomyrmex flavitarsus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dolichoderinae
Genus: Leptomyrmex
Species: L. flavitarsus
Binomial name
Leptomyrmex flavitarsus
(Smith, F., 1859)

Leptomyrmex flavitarsus side view

Leptomyrmex flavitarsus top view

Specimen labels

L. flavitarsus has been recorded in rainforest, including lowland secondary rainforest and montane rain¬forest. Nesting habits are unknown.

Identification

This species superficially resembles the two other dark species of Leptomyrmex known to occur in New Guinea, Leptomyrmex niger and Leptomyrmex melanoticus, but can be distinguished by the abundant pubescence on the head and body, especially the pronotum, which is lacking in the others. L. flavitarsus is also relatively larger and stouter (HW 1.18–1.45 mm; WL 3.25–3.68 mm) than the other two (L. niger HW 1.01–1.25 mm; WL 3.15–3.58 mm. L. melanoticus HW 0.99–1.06 mm; WL 3.32–3.76 mm), and closely resembles the pale Leptomyrmex puberulus, but is darker in color and lacks the pubescent eyes of L. puberulus. (Lucky and Ward 2010)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Indonesia (type locality), New Guinea.

Check distribution from AntMaps.

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Leptomyrmex flavitarsus for further details

Biology

These conspicuous ants are most often encountered individually or as small groups of 2 or 3 foragers on the surface of the ground any time of the day or night. Because of their long legs and thin bodies, they superficially resemble spiders. This is especially true when they are disturbed, as they extend their legs, raise their gasters, and run quickly to escape danger. This has led to their being given the common name "spider ants."

Nests are found in soil or in dead wood, either standing or on the ground, and are often at the base of trees. Colony sizes average a few hundred workers and a single queen. In all but a handful of species, the queen is wingless and worker-like, differing from workers only in being slightly larger and with an enlarged mesosoma. In a few species the queens are fully winged, as they are in most other ants.

When a large source of food is found, workers of Leptomyrmex will return to their nest and recruit additional workers to help utilise the newly found resource. They also use workers as "living storage vessels". These special workers, called repletes, accept liquids from returning foragers who transfer their liquid foods to these selected workers. These special workers continue to accept liquids until their gasters become greatly enlarged and extended. When enlarged, repletes cannot escape the nest and remain inside suspended from the ceiling. They can retain these fluids for extended periods and dispense it on demand when food is in short supply.

Castes

Queens of Leptomyrmex flavitarsus have not been collected.

Worker

Nomenclature

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

  • flavitarsus. Formica flavitarsus Smith, F. 1859a: 136 (w.) INDONESIA (Aru I.). Lucky & Ward, 2010: 34 (m.). Combination in Camponotus: Roger, 1863b: 4; in Camponotus (Tanaemyrmex): Emery, 1925b: 90; in Leptomyrmex: Shattuck, 1992c: 114.

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

Description

Worker

Lucky and Ward (2010) – measurements (n = 10) HL 1.74–1.99, HW 1.18–1.45, MFC 0.21–0.29, IOD 0.66–0.90, SL 3.26–3.62, EL 0.28–0.43, WL 3.25–3.68, PW 0.89–1.04, DPW 0.34–0.43, HTL 3.68–4.19, HTWmin 0.12–0.14, HTWmax 0.18–0.23, CI 0.67–0.73, SI 2.47–3.03, OI 0.06–0.15, HTC 0.55–0.71.

Medium sized species (HW 1.18–1.45 mm; WL 3.25–3.68 mm) with broad head (CI 0.67–0.73), widest anterior to eyes. Sides of head convex, genae straight to slightly concave anteriorly. Behind the eyes, head gently rounding to flat postocular margin. Approximately 15 teeth and denticles interspersed along mastica¬tory margin of mandible. Anterior clypeal margin weakly concave. Eyes positioned posterior to midline of head, small and round, convex and hairless, not reaching lateral margins of head. Antennae not compressed, scapes surpassing posterior margin of head by 3/5 their length.

Dorsal face of propodeum approximately as long as declivitous face, dorsal face with a slight transverse impression on anterior end. Petiolar node thick (DPW 0.34–0.43 mm), with rounded summit; anterior face short and perpendicular to base, with shallow median longitudinal groove. Posterior face of petiole long, flat and sloping, ventral surface flat, not projecting. Gaster broadly elliptical. Legs long and slender.

Surface distinctly shagreened and shining throughout, subopaque. Pubescence long and brownish, distrib¬uted all over the body, but especially prominent on the head, pronotum and gaster. Black, bristle-like hairs on clypeus, venter and gaster. Body generally dark brown with the tarsi, femoro-tibial joints and antennal funiculus yellow.

Type Material

The following notes on F. Smith type specimens have been provided by Barry Bolton (details):

Formica flavitarsus

Two worker syntypes in Oxford University Museum of Natural History. Labelled “Aru 14” and “Aru 45.” Donisthorpe (1932c: 452) records only one worker, but both specimens appear to come from the same series, and appear to have originally been mounted on a single card, that was later cut in half. Donisthorpe’s referral of this species to Camponotus is in error.

References

  • Emery, C. 1925d. Hymenoptera. Fam. Formicidae. Subfam. Formicinae. Genera Insectorum 183: 1-302 (page 90, Combination in Camponotus (Tanaemyrmex))
  • Lucky, A. 2011. Molecular phylogeny and biogeography of the spider ants, genus Leptomyrmex Mayr (Hymenoptera: Formicidae). Molecular Phylogenetics and Evolution 59: 281-292.
  • Lucky, A. & Ward, P.S. 2010. Taxonomic revision of the ant genus Leptomyrmex Mayr. Zootaxa 2688: 1-67.
  • Roger, J. 1863b. Verzeichniss der Formiciden-Gattungen und Arten. Berl. Entomol. Z. 7(B Beilage: 1-65 (page 4, Combination in Camponotus)
  • Shattuck, S. O. 1992c. Generic revision of the ant subfamily Dolichoderinae (Hymenoptera: Formicidae). Sociobiology 21: 1-181 (page 114, Combination in Leptomyrmex)
  • Smith, F. 1859a. Catalogue of hymenopterous insects collected by Mr. A. R. Wallace at the islands of Aru and Key. [part]. J. Proc. Linn. Soc. Lond. Zool. 3: 132-158 (page 136, worker described)