|Based on Barden et al., 2017. Note only selected Leptomyrmex species are included.|
L. nigriceps has been recorded in rainforest, Agathis woodland, cloud forest and low, closed riparian forest. Nests have been found in rotting stumps.
- 1 Identification
- 2 Distribution
- 3 Biology
- 4 Castes
- 5 Nomenclature
- 6 References
L. nigriceps resembles the other two New Caledonian Leptomyrmex (Leptomyrmex pallens and Leptomyrmex geniculatus) but can be recognized by its distinctive color pattern: dark head and gaster on an otherwise orange body. This species appears to be restricted to the ultramafic southern tip of the island, where it occurs in sympatry or parapatry with L. pallens. (Lucky and Ward 2010)
Keys including this Species
Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
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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.
Queens have yet to be collected.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- nigriceps. Leptomyrmex pallens var. nigriceps Emery, 1914f: 418 (w.) NEW CALEDONIA. Lucky & Ward, 2010: 42 (m.). Subspecies of pallens: Wheeler, W.M. 1934c: 109. Raised to species: Lucky & Ward, 2010: 42.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Lucky and Ward (2010) – measurements (n = 9) HL 1.68–1.90, HW 0.92–1.01, MFC 0.20–0.25, IOD 0.54–0.60, SL 3.17–3.47, EL 0.29–0.36, WL 3.03–3.41, PW 0.75–0.86, DPW 0.27–0.33, HTL 3.57–4.11, HTWmin 0.10–0.14, HTWmax 0.14–0.18, CI 0.52–0.56, SI 3.27–3.56, OI 0.08–0.10, HTC 0.65–0.95.
As in Leptomyrmex geniculatus, but with femora unicolorous pale and head black. Gaster and head, excluding mandi¬bles and antennae, black, with remainder of body pale orange.
Lucky and Ward (2010) – measurements (n = 1) HL 1.24, HW 0.97, SL 0.36, EL 0.53, HTL 3.90, CI 0.78, SI 0.37, SI2 0.81.
Lucky and Ward (2010) – type material examined, Syntype, 1 worker, New Caledonia: La Madeleine (Sarasin & Roux) Museo Civico di Storia Naturale, Genoa
- Emery, C. 1914f. Les fourmis de la Nouvelle-Calédonie et des îles Loyalty. Nova Caled. A Zool. 1: 393-437
- Lucky, A. 2011. Molecular phylogeny and biogeography of the spider ants, genus Leptomyrmex Mayr (Hymenoptera: Formicidae). Molecular Phylogenetics and Evolution 59: 281-292. doi:10.1016/j.ympev.2011.03.004
- Lucky, A. & Ward, P.S. 2010. Taxonomic revision of the ant genus Leptomyrmex Mayr. Zootaxa 2688: 1-67. PDF