Pheidole fervida

This species seems to be restricted to cool-temperate to warm-temperate humid areas in East and Southeast Asia. It usually inhabits well-developed natural forests, man-made woody habitats (timber plantations, woody gardens, etc.) and forest edges, and nests mainly in rotting logs and other wood material, and sometimes in the litter/soil, and among root networks of vegetation on the rocks. (Eguchi 2008)

Identification
Eguchi (2008) - Posterior margin of head of the minor is generally more convex in N. Vietnamese populations than in Korean and Japanese populations. However, in population(s) of Lao Cai and Lai Chau, N. Vietnam, the minor is variable not only in the convexity of posterior margin of head but also in the sculpture on frons and vertex. It is also possible that P. fervida recognized here actually includes two or more sibling species.

A variant of P. fervida (the minor having sculptured frons and vertex) is similar to Pheidole ryukyuensis Ogata. However, in the major of P. ryukyuensis posterior margin of head in full-face view is rather deeply concave; and in the major and minor of P. ryukyuensis mound on the posterior slope of promesonotal dome is almost absent (see also Ogata 1982). Another variant of P. fervida (the minor having smooth head) is similar to a variant of Pheidole vulgaris (the major having almost smooth vertexal lobe). However, in the major of P. vulgaris the head rather long; and in the major and minor of P. vulgaris the mound on the posterior slope of promesonotal dome is almost absent.

Distribution
Known from N. Vietnam, mainland Japan, N. Ryukyus and Korean Peninsula.

Distribution based on Regional Taxon Lists
Oriental Region: Vietnam. Palaearctic Region: China, Democratic Peoples Republic of Korea, Japan, Republic of Korea, Russian Federation.

Biology
Watanabe et al. (2019) conducted an observational study of the aphid species Macrosiphoniella yomogicola (Matsumura) and the ants that tended their colonies. This aphid has been found to be an obligate ant mutualist. Nine aphid colonies were monitored in Sapporo, Japan over a multi-week period in August and September. Lasius japonicus, Tetramorium tsushimae and Pheidole fervida were found attending the aphids, with each ant species exclusively tending the aphid colony where each was observed. The only aphid colonies to survive through the monitoring period were those tended by Lasius japonicus. This suggests, but the he number of observed colonies was not sufficient to conclude, that P. fervida is not a mutualist of the aphid and is only opportunistically tending the colonies where it was found.

Nomenclature

 *  fervida. Pheidole fervida Smith, F. 1874: 406 (s.q.) JAPAN. Forel, 1900e: 285 (w.); Wheeler, W.M. 1928d: 107 (q.); Ogata, 1982: 195 (m.); Imai, 1966: 119 (k.). Current subspecies: nominal plus kwazana. See also: Kupyanskaya, 1990: 124; Eguchi, 2008: 28.

Type Material
Eguchi (2008) - Syntypes: major & queen, Hiogo [Hyogo, Japan], not examined.

Worker
Eguchi (2008) - Major (n=5). — HL 1.30–1.43 mm; HW 1.31–1.47 mm; CI 94–104; SL 0.68–0.78 mm; SI 50–53; FL 0.88–1.06 mm; FI 66–73. Minor (n=5). — HL 0.62–0.66 mm; HW 0.58–0.63 mm; CI 88–95; SL 0.58–0.72 mm; SI 94–124; FL 0.60–0.77 mm; FI 102–133.

Major — Head in full-face view relatively shallowly concave posteriorly, in lateral view roundly convex dorsally, not impressed on vertex; frons and vertex rugose longitudinally, with interspaces smooth; vertexal lobe smooth and shining (but rarely dimly rugosed); frontal carina weak, or inconspicous just as rugula(e); antennal scrobe almost absent, or present but inconspicuous; median part of clypeus smooth, without a median longitudinal carina absent (rarely with a very weak carina); hypostoma with median and submedian processes in addition to conspicuous lateral processes; submedian processes always conspicuous, but median process often less conspicuous than submedian processes; antenna with a 3-segmented club; maximal diameter of eye longer than antennal segment X; outer surface of mandible smooth (excluding the basal area), with relatively long decumbent hairs. Promesonotal dome sparsely rugose transverselly, with interspaces smooth and shining, in lateral view with a low to inconspicuous mound on its posterior slope; humerus not or very weakly produced laterad; the dome at the humeri as broad as at the bottom, or narrower than at the bottom. Petiole longer than postpetiole (excluding helcium); postpetiole not massive, sometimes with its lateral corner forming a conspicuous horn. First gastral tergite smooth and shining entirely.

Minor — Dorsum of head variable in sculpture, usually rugoso-reticulate or rugoso-punctate at least partly, but sometimes smooth and shining almost entirely; preoccipital carina present dorsally and laterally, but often very weak dorsally; median part of clypeus smooth and shining; median longitudinal carina absent, or present but inconspicuous; antenna with a 3-segmented club; scape usually exceeding posterior margin of head by the length of antennal segment II or more; maximal diameter of eye almost as long as or shorter than antennal segment X. Dorsum of promesonotal dome smooth and shining with several rugulae or rugoso-reticulate with enclosures almost smooth and shining, or rarely rugoso-punctuate largely; the dome in lateral view with a low to inconspicuous mound on its posterior slope; humerus of the dome in dorsal-oblique view hardly or very weakly produced laterad; mesopleuron, metapleuron and lateral face of propodeum usually punctured very weakly or weakly. Petiole longer than postpetiole (excluding helcium); postpetiole not massive.