Leptomyrmex erythrocephalus

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Leptomyrmex erythrocephalus
Leptomyrmex erythrocephalus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dolichoderinae
Genus: Leptomyrmex
Species: L. erythrocephalus
Binomial name
Leptomyrmex erythrocephalus
(Fabricius, 1775)

Leptomyrmex erythrocephalus side view

Leptomyrmex erythrocephalus top view

Specimen labels

Synonyms

L. erythrocephalus has been recorded in wet sclerophyll, dry sclerophyll, rainforest, gallery rainforest and beach scrub. Nests occur in the ground, under rocks, in soil at the base of trees and under or in logs. (Lucky and Ward 2010)

Identification

Lucky and Ward (2010) – In the Sydney region, where L. erythrocephalus is sympatric with Leptomyrmex cnemidatus, the two species can be quite difficult to distinguish, but the following characters will aid in separating them: in L. erythrocephalus, the central portion of clypeus, excluding the anterior margin presents 0–2 black setae (2–4 in L. cnemidatus); if 2 setae are present then these are separated by 0.25 mm or more (< 0.25 mm in L. cnemidatus). Outside of the Sydney region geographic distribution can also help distinguish these species: L. erythrocephalus occurs coastally and inland from Victoria to the Sydney area, but farther north to the Queensland border it inhabits only inland areas (> 100km from the coastline), whereas L. cnemidatus populations remain within 100 km of the coast.

In color pattern L. erythrocephalus resembles Leptomyrmex ruficeps, but the latter is confined to northern Queensland. The rounded postocular margin also helps to distinguish L. erythrocephalus (elongate and constricted in L. ruficeps). L. erythrocephalus may be difficult to distinguish from some individuals of Leptomyrmex wiburdi, which possess the typical L. erythrocephalus color pattern. The large size (HW 1.31–1.47 mm; WL 4.20–4.64 mm; in L. wiburdi HW 1.15–1.33 mm; WL 3.06–3.65 mm), narrower head (CI 0.59–0.62 mm; in L. wiburdi CI 0.66–0.70) and longer scapes (SI 2.87–3.20; in L. wiburdi SI 2.29–2.64) will identify L. erythrocephalus upon close examination.

Identification Keys including this Taxon

Distribution

Distribution based on Regional Taxon Lists

Australasian Region: Australia (type locality).

Check distribution from AntMaps.

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Leptomyrmex erythrocephalus 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 erythrocephalus 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.

  • erythrocephalus. Formica erythrocephala Fabricius, 1775: 391 (w.) AUSTRALIA. Emery, 1891a: 152 (m.); Wheeler, G.C. & Wheeler, J. 1951: 179 (l.); Imai, Crozier & Taylor, 1977: 345 (k.). Combination in Leptomyrmex: Mayr, 1862: 696. Senior synonym of clarki, froggatti, mandibularis, unctus: Lucky & Ward, 2010: 30. See also: Wheeler, W.M. 1915d: 265; Wheeler, W.M. 1934c: 85.
  • froggatti. Leptomyrmex froggatti Forel, 1910b: 57 (w.m.) AUSTRALIA. See also: Wheeler, W.M. 1934c: 101. Junior synonym of erythrocephalus: Lucky & Ward, 2010: 30.
  • mandibularis. Leptomyrmex erythrocephalus var. mandibularis Wheeler, W.M. 1915d: 268 (w.) AUSTRALIA. Subspecies of erythrocephalus: Wheeler, W.M. 1934c: 87. Junior synonym of erythrocephalus: Lucky & Ward, 2010: 30.
  • clarki. Leptomyrmex erythrocephalus subsp. clarki Wheeler, W.M. 1934c: 117 (w.) AUSTRALIA. Junior synonym of erythrocephalus: Lucky & Ward, 2010: 30.
  • unctus. Leptomyrmex erythrocephalus subsp. unctus Wheeler, W.M. 1934c: 87 (w.) AUSTRALIA. Junior synonym of erythrocephalus: Lucky & Ward, 2010: 30.

Type Material

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

Description

Lucky and Ward (2010) – measurements (n = 10) HL 2.17–2.41, HW 1.31–1.47, MFC 0.27–0.32, IOD 0.78–0.93, SL 3.90–4.29, EL 0.41–0.50, WL 4.20–4.64, PW 1.21–1.44, DPW 0.44–0.56, HTL 4.80–5.38, HTWmin 0.13–0.17, HTWmax 0.27–0.32, CI 0.59–0.62, SI 2.87–3.20, OI 0.09–0.12, HTC 0.42–0.58.

As in Leptomyrmex cnemidatus, but larger on average: HW 1.31–1.47 mm; WL 4.20–4.64 mm (L. cnemidatus HW1.20–1.39 mm; WL 3.79–4.32 mm). Typical color pattern consisting of black body with contrasting rufotestaceous head, antennae and tarsi. In northern half of range (> 100km inland, e.g. Girraween NP) some individuals become variable in coloration, with head black and/or variable amounts of black and rufotestaceous color occuring on mesosoma.

Male

Lucky and Ward (2010) – measurements (n = 9) HL 1.60–1.80, HW 1.10–1.30, SL 0.56–0.64, EL 0.55–0.71, HTL 4.57–5.03, CI 0.65–0.76, SI 0.46–0.55, SI2 1.03–1.20. Emery’s (1891) description of the male of L. erythrocephalus is probably a misidentification, as it does not correspond with known males of this species.

References

  • Emery, C. 1883. Alcune formiche della Nuova Caledonia. Bull. Soc. Entomol. Ital. 15: 145-151 (page 147, queen described)
  • Emery, C. 1891b. Le formiche dell'ambra Siciliana nel Museo Mineralogico dell'Università di Bologna. Mem. R. Accad. Sci. Ist. Bologna (5)1:141-165 (page 152, male described)
  • Fabricius, J. C. 1775. Systema entomologiae, sistens insectorum classes, ordines, genera, species adiectis synonymis, locis, descriptionibus, observationibus. Flensburgi et Lipsiae [= Flensburg and Leipzig]: Korte, 832 pp. (page 391, worker described)
  • Imai, H. T.; Crozier, R. H.; Taylor, R. W. 1977. Karyotype evolution in Australian ants. Chromosoma (Berl.) 59: 341-393 (page 345, karyotype described)
  • 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.
  • Mayr, G. 1862. Myrmecologische Studien. Verh. K-K. Zool.-Bot. Ges. Wien 12: 649-776 (page 696, Combination in Leptomyrmex)
  • Wheeler, G. C.; Wheeler, J. 1951. The ant larvae of the subfamily Dolichoderinae. Proc. Entomol. Soc. Wash. 53: 169-210 (page 179, larva described)
  • Wheeler, W. M. 1915e. The Australian honey-ants of the genus Leptomyrmex Mayr. Proc. Am. Acad. Arts Sci. 51: 255-286 (page 265, see also)
  • Wheeler, W. M. 1934c. A second revision of the ants of the genus Leptomyrmex Mayr. Bull. Mus. Comp. Zool. 77: 69-118 (page 85, see also)