New haplotype and inter‐strain reproductive compatibility of W olbachia ‐uninfected alfalfa weevil, H ypera postica ( C oleoptera: C urculionidae), in J apan

H ypera postica is a univoltine invasive pest of alfalfa, M edicago sativa , in N orth A merica. In J apan, H . postica was first found in 1982 from F ukuoka and O kinawa P refectures and became a serious pest of C hinese milk vetch, A stragalus sinicus , cultivated as a honey source for humans and green manure for rice. In N orth A merica, three strains, W estern, E astern and E gyptian, have been identified and the W estern strain is infected with W olbachia , which causes complete inter‐strain reproductive incompatibility. In contrast, only W estern and E gyptian strains had been reported throughout J apan and none of the W estern strain examined for the F ukuoka populations in northern K yushu was infected with W olbachia . First, we screened populations from northern K yushu collected since 1982 for geographical and chronological distribution of the E astern strain. The E astern strain has been found at low frequencies since 1985 and is still present in 2014. Second, we experimentally tested our hypothesis that inter‐strain crosses between uninfected W estern‐strain males and E gyptian‐strain females should produce viable offspring. We crossbred virgin adults reared individually from field‐collected larvae and confirmed that the F 1 eggs of crosses between the W estern‐strain males and the E gyptian‐strain females develop successfully into larvae.