Myrmica jessensis

Radchenko and Elmes (2010) - In Japan M. jessensis is primarily a grassland species (Ichinose 1990) and we found that it was quite common on mown roadside verges on Hokkaido island. More generally we can say that it is a species of open areas at altitudes up to 1700 m and sometimes it is quite abundant on riverbanks (Kondoh 1994). It builds nests in soil, often under stones (Imai et al. 2003; Radchenko 2005). A nuptial flight was observed in September (Ichinose 1990).

Identification
A member of the lobicornis species group and it most resembles Myrmica eidmanni, from which it differs principally by its narrower frons and shallower metanotal groove. (Radchenko and Elmes 2010)

Key to Myrmica of species of East Siberia, Russian Far East, Mongolia, Korean Peninsula, northern China, and Japan

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

Nomenclature

 *  jessensis. Myrmica lobicornis var. jessensis Forel, 1901e: 371 (w.) JAPAN. Subspecies of lobicornis: Weber, 1948a: 286. Raised to species: Collingwood, 1976: 302; Kupyanskaya, 1986a: 85; Kupyanskaya, 1990: 110. Senior synonym of hyungokae: Radchenko, 2005b: 141. See also: Radchenko & Elmes, 2010: 157.
 * hyungokae. Myrmica hyungokae Elmes, Radchenko & Kim, 2001: 109, figs. 1e-h (w.) KOREA. Junior synoym of jessensis: Radchenko, 2005b: 141.

Etymology
Radchenko and Elmes (2010) - from name Jesso combined with the Latin suffix ensis = place of origin, to indicate that the type region is Jesso (modern Hokkaido, Japan). In the 16th century Jesso was the northern border areas of Japan, including Hokkaido, Sakhalin and Kurilen islands inhabited by the Ainu peoples.