Population Structure of Two Flightless Weevils of Genus Scepticus Roelofs (Coleoptera, Curculionidae) with Seashore Habitat in Japan

To elucidate the genetic population structure of two coastal weevils, Scepticus griseus and S. tigrinus, we conducted molecular phylogenetic analyses of the mitochondrial DNA cytochrome c oxidase subunit I (COI) region (1308 bp) and cytochrome c oxidase subunit II (COII) region (584 bp). A total of 650 individuals (S. griseus, 444 individuals; S. tigrinus, 206 individuals) were obtained from 64 sites. The haplotype networks of both species showed three major lineages with roughly regional distribution. However, the two species show quite different genetic structures; S. griseus has a complicated structure while that of S. tigrinus is simple. We hypothesize that the genetic structure of each of these two weevil species reflects climatic oscillations during the Pleistocene, and the differences in genetic structure between S. griseus and S. tigrinus may represent a unique evolutionary history scenario in each species.