Bee fauna in coastal sand dunes of Ariakehama and ten islands along the Seto Inland Sea, western Japan

The bee fauna in coastal sand dunes of Ariakehama (mainland of Shikoku Island) and ten islands along the Seto Inland Sea, western Japan were investigated. In Ariakehama, bees were quantitatively collected from April to October in 2008, and the summer bee fauna on the coastal shrub, Vitex rotundifolia, was surveyed in ten islands between 2003 to 2021. In Ariakehama, the bee diversity was only 20 species, like in some other study sites of coastal sand dunes in Japan. Megachile kobensis and Apis melifera were the dominant species. Compared to other coastal sand dunes in Japan, remarkable characteristics of the bee fauna in Ariakehama were the scarcity of Hylaeus spp. and Lasioglossum frigidum. These bees were common in some islands in the Seto Inland Sea. The reasons for their rarity in Ariakehama were discussed.