Species composition of anthophilous Diptera and Hymenoptera in the Daisetsu Mountains

The species composition of anthophilous Diptera and Hymenoptera on three alpine flowers was investigated at an altitude of 1,950-m on Mt. Hakuundake in the Daisetsu Mountains, Hokkadio, Japan. A total of 317 individuals from 35 species of nine families was collected. The most abundant insect family was Syrphidae (64.4% of individuals), followed by Anthomyiidae (16.4%) and Halictidae (6.0%). On Sorbus matsumurana (Rosaceae), 150 individuals from 27 species were collected; the most abundant was Syrphidae, followed by Empididae and Tenthredinidae. On Weigela middendorffiana (Caprifoliaceae), 103 individuals from 22 species were collected; the most abundant was Syrphidae, followed by Halictidae and Apidae. On Trollius riederianus (Ranunculaceae), 64 individuals from 8 species were collected; the most abundant was Anthomyiidae, followed by Syrphidae and Apidae. Species diversity (1/D) was the highest on W. middendorffiana (9.7) and the lowest on T. riederianus (3.9). The index of similarity, QS, was largest for the combination of S. matsumurana and W. middendorffiana (0.71), and smallest for S. matsumurana and T. riederianus (0.28).