Revision of genus Brenthis (Lepidoptera, Nymphalidae) in Japan by mating experiments

Abstract

　Genus Brenthis in Japan has hitherto been divided into two species, each with two subspecies. Mating experiments using the cage pairing method were carried out to clarify the degree of reproductive isolation between each of the subspecies of both species. Cage pairing experiments with B. ino showed that the two subspecies easily copulate. The inter-subspecific F1 hybrids of the forward and reverse crosses developed to maturity, and normal adults emerged with a normal sex ratio. The backcrossing results showed that F1 individuals could reproduce. As there was no reproductive isolation between these subspecies, the two subspecies of B. ino in Japan should be regarded as a single taxon. In contrast, male and female individuals of the subspecies of B. daphne did not copulate. As complete mating isolation between two subspecies of B. daphne appears to exist, the two subspecies of B. daphne in Japan should be regarded as distinct species.