Morphological, genetic and behavioural analyses of a hybrid zone between the ground beetles carabus lewisianus and C. albrechti (Coleoptera, Carabidae) : asymmetrical introgression caused by movement of the zone?

摘要: We analysed the putative hybrid zone between ground beetles Carabus lewisianus Breuning and C. albrechti Morawitz from Kanto Tanzawa Mountains in central Honshu, Japan, using morphological, genetic, behavioural data. Canonical discriminant analysis of three external five genital morphological characters revealed an apparent gap, suggesting restricted sympatry contact zone. RFLP molecular phylogenetic analyses mitochondrial gene ND5 that haplotypes originating C. lewisianus introgressed extensively into C. albrechti. Fitting tanh curves to (external genital) genetic showed differential cline widths centres, stronger selection for morphology with narrower widths, extensive introgression nuclear genes responsible relative those controlling range Linkage disequilibria did not differ zero, sufficient recombination occurred but effect small sample sizes was negligible. Mate choice trials demonstrated males a weak significant preference conspecific mates. interpret these patterns as evidence (1) partial reproductive isolation presumably by postmating processes; (2) against intermediate morphologies, (3) independent responses different evolutionary forces may cause movement clines morphology. The boundaries have resulted particular species distribution study area. © 2005 Linnean Society London, Biological Journal Society, 2005, 86, 79–94.