Strumigenys nidifex

A Fiji endemic. This species is the largest Strumigenys known from Fiji and is the best known biologically. It has been found nesting in logs and under rocks. It prefers forest habitats but has also been found in disturbed areas. Foragers have been collected on numerous occasions, a relatively rare occurrence for most Strumigenys species.

Identification
Bolton (2000) - A member of the Strumigenys szalayi-group. A very distinctive large species, apparently restricted to the Fiji Islands. It is the only member of the group to have two intercalary denticles and retain spongiform tissue on the petiole.

Sarnat and Economo (2012) - Strumigenys nidifex is one of the most conspicuous dacetines of the Fijian fauna. It is the largest of the species, with a distinctive broad head that is impressed posterior to the vertex and bears a preocular impression on the ventrolateral margin of the head. All surfaces of the head, mesosoma, waist and coxae are punctate-reticulate. The nearest relative to S. nidifex is Strumigenys sp. FJ01. The gaster of the former is sculptured basally, but is otherwise strongly polished and shiny. The gaster of the latter is strongly punctate-striate the entire length of the first segment. The males of the two differ, with those of S. nidifex being larger with a distinctly elongated head, while the male of Strumigenys sp. FJ01 is smaller with a much rounder head. The queen of Strumigenys sp. FJ01 is also distinctly smaller, especially with regard to the mesonotum. However, the series of S. nidifex from Koro are all smaller, and the queens of that series are more similar to those of Strumigenys sp. FJ01 than to those of its conspecifics on other islands, with the caveat that its gaster is polished and shiny. Both species occur sympatrically in the Nadarivatu area. The only other species in Fiji with a preocular notch is Strumigenys rogeri, which is easily separated by its significantly smaller size, yellow brown color, and mandible with two pre-apical teeth. The other large Strumigenys in Fiji all lack the preocular impression.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Fiji.

Biology
An excellent account of a laboratory-raised colony is described by E. O. Wilson from a colony collected from Nadala (Viti Levu) during his expedition to Fiji. This colony was sent back to his laboratory in the United States and kept for two years. They produced produced queens and hunted a variety of small arthropods. The oviposition and hunting behavior is explained in some detail. Strumigenys nidifex is thus one of the very few native Fijian ants for which any detailed natural history is known.

Nomenclature

 *  nidifex. Strumigenys nidifex Mann, 1921: 464, fig. 23 (w.q.m.) FIJI IS. Wheeler, G.C. & Wheeler, J. 1955a: 140 (l.). See also: Brown, 1971c: 81; Bolton, 2000: 905.

Worker
Bolton (2000) - TL 4.7-5.1, HL 1.38-1.48, HW 0.98-1.13, CI 71-76, ML 0.62-0.64, MI 43-46, SL 0.88-0.94, SI 83-90, PW 0.46-0.51, AL 1.34-1.44 (10 measured).

Apex of mandible with 2 intercalary denticles. Postbuccal groove inconspicuous. With head in profile dorsum very broadly and deeply concave from just behind level of eye to close to occipital margin; this concavity extending as a broad groove across entire width of vertex. Ventral surface of head with a distinct postocular concavity. Ventral surface of petiole with a narrow spongiform curtain, at least on posterior two-thirds of length. Entire alitrunk reticulate-punctate. Pronotal dorsum with a pair of erect hairs, as well as those at the humeri. Colour uniform dark brown to blackish-brown.

Type Material
Bolton (2000) - Syntype workers, queens and males, FIJI IS: Viti Levu, Nadarivatu (W. M. Mann) [examined].