Comparing spatial patterns of population density, biomass, and genetic diversity patterns of the habitat generalist mayfly Isonychia japonica Ulmer (Ephemeroptera:Isonychiidae) in the Chikuma–Shinano River basin

AbstractEvaluating the relative connectivity of populations within and among streams in a riverine landscape is crucial to developing a better understanding of stream ecology. Molecular markers provide a reasonable approach to assess the connectivity of populations and to evaluate inherent properties of populations, such as genetic diversity. Many previous investigators of genetic differentiation within species at the regional level have focused on habitat specialists, but habitat generalists, with their continuous and broad distribution across a wide variety of habitats, have not been a focus of research. We examined a typical habitat generalist mayfly, Isonychia japonica Ulmer (Ephemeroptera:Isonychiidae) by evaluating its population density, biomass, and genetic structure at 42 study sites in the largest river system in the Japanese Archipelago, the Chikuma–Shinano-gawa River basin. We conducted genetic analysis of the mitochondrial DNA cytochrome oxidase c subunit I (COI) region (610 base pairs). We c...