Abstract
Population connectivity of aquatic organisms is an important factor for sustaining the robustness of metapopulation in a basin-scale as well as for interpreting the properties of respective local populations. We examined the genetic structure of 30 Stenopsyche marmorata (Tricoptera) local populations in 4 catchments in South-Central Miyagi Prefecture, Japan using AFLP markers, and evaluated their dispersal pattern. We constructed a dendrogram using q, and found that 7 populations in headwater were isolated from another area in the basins. Although previous studies on S. marmorata adult flight within streams reported most of the females fly upstream along a watercourse after mating, our results indicated high possibility of non-directional adult dispersal due to wind. The results also suggested a strong potential for DNA polymorphic analysis to enhance understanding of the population connectivity and dispersal patterns of aquatic organisms in a basin scale.