MEPS 657:135-146 (2021)  -  DOI: https://doi.org/10.3354/meps13553

ABSTRACT: Recent molecular ecological studies have focused on how the relationships between physical and ecological factors influence marine biogeography. Comparative phylogeography using closely related species is a powerful approach to evaluate the role of ecological traits in the genetic variation of marine organisms. In the present study, we compared ecological traits and genetic variation in 3 species of the intertidal snail genus Monodonta that co-occur in the Japanese and Ryukyu archipelagoes. We found that M. labio was dominant in sheltered habitats and M. perplexa was dominant in wave-exposed habitats, while M. confusa showed no habitat specificity. This indicates that M. labio and M. perplexa are habitat specialists regarding wave exposure, while M. confusa is a generalist. M. labio and M. perplexa showed lower genetic diversity and greater genetic differentiation among populations than M. confusa. Our findings support the specialist-generalist variation hypothesis in a well-connected marine environment.

KEY WORDS: Specialist-generalist variation hypothesis · SGVH · Phylogeography · Genetic structure · Habitat range · Intertidal gastropods · Monodonta