Microhabitat contributes to microgeographic divergence in threespine stickleback.

摘要: Since the New Synthesis, most migration-selection balance theory has predicted that there should be negligible differentiation over small spatial scales (relative to dispersal), because gene flow erode any effect of divergent selection. Nevertheless, are classic examples microgeographic divergence, which suggests can arise under specific conditions: exceptionally strong selection, phenotypic plasticity in philopatric individuals, or nonrandom dispersal. Here, we present evidence morphological variation within lake and stream populations threespine stickleback (Gasterosteus aculeatus). It seems reasonable assume a given population fish is well-mixed. However, found this assumption untenable. We examined trap-to-trap 34 traits measured on from 16 lakes streams. Most varied appreciably among traps populations. Both between-trap distance microhabitat characteristics such as depth substrate explained some within-population variance. Microhabitat was also associated with genotype at particular loci but no genetic isolation by distance, implying heritable habitat preferences may contribute variation. Our study adds growing divergence occur across individuals' daily dispersal neighborhood where expected strong.