Influence of landscape on the population genetic structure of the alpine butterfly Parnassius smintheus (Papilionidae)

Four microsatellite DNA markers were developed which were used to examine t he relationship between landscape and population genetic structure among a set of populations of the butterfly Parnassius smintheus located in the foo thills of the Canadian Rockies. Detailed information on the dispersal of ad ult butterflies among this same set of populations was available. Simple an d partial Mantel tests were used to examine the relationships between genet ic distances, predicted rates of dispersal, and a number of landscape varia bles, all measured pairwise for 17 sample sites. Nei's standard genetic dis tance was negatively correlated with predicted dispersal. We observed a sig nificant pattern of isolation by distance at a very small spatial scale. Th e distance between sites that was through forest was a stronger predictor o f genetic distance than the distance through open meadow, indicating a sign ificant effect of landscape on population genetic structure beyond that of simple isolation by distance. Our results suggest that rises in the tree-li ne in alpine areas, caused by global warming, will lead to reduced gene flo w among populations of P. smintheus.