Data for: Relationships between reproductive character displacement in genital morphology and the population-level cost of interspecific mating: Implications for the Templeton effect

Natural selection against maladaptive interspecific reproductive interactions may cause greater divergence in mating traits between sympatric populations than between allopatric populations in a pair of species, known as reproductive character displacement (RCD), evidence for the lock-and-key hypothesis of genital evolution. However, the relative importance of various processes contributing to RCD in genital morphology (e.g., reinforcement, reproductive interference, and population filtering or the Templeton effect) is not clear. Here, we examined hypotheses for RCD in genital morphology, with a special focus on the Templeton effect (which predicts that only highly differentiated populations can exist in sympatry). We examined population-level fitness costs in interspecific mating between Carabus maiyasanus and C. iwawakianus with RCD in genital morphology. A mating experiment using populations with various degrees of RCD in genital morphology showed no evidence for consistently lower i...