1973 年 23 巻 4 号 p. 160-170
As a part of our biofaunistic surveys on the wild bees in Hokkaido, periodical sampling was made in 1966 (supplemented in 1967) two times per month at a littoral sand-dune vegetation at Hama-Koshimizu, Eastern Hokkaido, facing the Okhotsk Sea. The halictine bees, especially Evylaeus, occupy the majority of the total 55 species and the total of 1,045 individuals sampled. Bumble bees were second in numbers of individuals. Compared with the bee fauna in Central Hokkaido, the scarcity of the leaf cutting bees (Megachilidae) and anthophorine bees (especially Ceratina) is remarkable. Because of the severe climate, the activity of some vernal species shows a delay of nearly one month compared with that in Sapporo, resulting in the temporary co-existence in June of both vernal and early summer bees in Sapporo. The area is relatively free from the invasion of exotic plants. The visits to native plants show various relations between the amount and duration of blooming and bee visits, with the highest visits to Rosa rugosa, Coelopleurum lucidum and Geranium miyabei. But Taraxacum officinale, one of the predominant escapes in Hokkaido, already occupies the first rank in the visits, amounting to 29.4 per cent of the total bees sampled.