Myrmica kotokui

Japanese Name

Shiwa-kushike-ari

Forel, A. (1911) Die Ameisen des K. Zoologischen Museums in MŸnchen. Sitzungsberichte der Kšniglich Bayerischen Akademie der Wissenschaften Mathematisch-Physikalische Klasse 1911: 249-303.

Myrmica ruginodis var. kotokui Forel, 1911, Myrmica kotokui: Collingwood, 1976, Myrmica ruginodis kotokui: Onoyama, 1989,

Total length of workers around 4 - 5.5 mm. Body color brown to blackish brown; legs lighter. Antennal scape gently curved near the base. Anterior margin of clypeus convex in the middle; the clypeal rugae projecting anteriorly to appear as denticles. Thoracic dorsum with strong rugae, many of them longitudinal. Rugae on posterior border of mesonotal dorsum raised. Propodeal spines usually long. Anterior base of 1st gastral tergite with longitudinal rugae.

This species is not very different from the European M. ruginodis Nylander and perhaps properly conspecific. Onoyama (1989) suggested that it might best be considered a subspecies of ruginodis. Detailed study, including comparison with ruginodis specimens from the Far East, is required. Mizutani (1981) stated that the populations of dry riverbeds near Sapporo are polygynous, while those of mountainous regions are monogynous, and that reproductive methods and head width are different in these two areas. He recognized small-female "microgyna" and large-female "macrogyna" variants. Future study is clearly required (no relevant specimens are currently to hand).
This species nests under stones, in the soil, and in fallen rotting logs, etc. It is very common in cool regions. Winged reproductives fly from September to early October.

Hokkaido, Honshu, Shikoku, Kyushu, Yaku I.; Sakhalin, Korean Peninsula.