Southern origin beetle, Anomala albopilosa (Coleoptera: Scarabaeidae), has recently expanded its distribution to central Japan, and where A. albopilosa invaded, the number of endemic related-species such as A. cuprea and A. japonica has been decreasing. To reveal this mechanism, reproductive interference, one of the interspecific interactions between related-species, was confirmed. In the field, sex pheromone trap for A. albopilosa hardly attracted other species, while that for A. cuprea attracted A. albopilosa. Regardless of species, each species copulated in the cage. The females of endemic species that copulated with the males of A. albopilosa hardly laid eggs, while females of A. albopilosa laid eggs and formed hybrids regardless of the mating species, and hybrids were fertile. From the genetic analysis, there were no individuals that appeared to be other species or hybrids in the clade of A. albopilosa, while individuals that appeared to be A. albopilosa or hybrids were slightly contained in the clade of endemic species. From these results, females of A. albopilosa are caught no negative effect from males of other species because females of A. albopilosa do not attract other species. On the other hand, females of A. cuprea attract males of A. albopilosa, and the number of eggs may decrease due to interspecific copulation.