Stenamma owstoni

Japanese Name

Naga-ari

Wheeler, W. M. (1906) The ants of Japan. Bulletin of the American Museum of Natural History 22: 301-328.

Total length of workers around 2.5 - 4 mm. Body color yellowish brown to dark reddish brown. Similar to S. nipponense, but the eyes larger (longest diameter exceeding length of 9th antennal segment).

Judging from Arnoldi's (1975) description of the Russian species S. kurilense , S. owstoni is similar, but kurilense is smaller and less slender. Arnoldi indicated that the petiole of S. kurilense is shorter and higher than that of S. owstoni. But S. owstoni is more variable in size, so that the proportions and the shape of the petiole are substantially variable. Thus, the identity of S. kurilense versus S. owstoni needs examination. S. owstoni is found in woodland or its margins, and nests in the soil. Kubota (1988) reported many seeds of the plant Clethra barbinervis from a nest. This suggests that S. owstoni is a gramnivore, which harvests seeds for larval food. Forel (1911) recorded it from Hokkaido, but we suppose this record to be a misidentification. The northernmost confirmed distribution record is from Iwate Prefecture (Tanaka, 1974a). A rather rare species.

Honshu, Shikoku, Kyushu; Mainland China.