Genetic consequences of an introduction-colonization process in an endangered butterfly species

From a theoretical point of view, the genetic consequences of foundation ev ents are relatively well known but few field experimental data are availabl e on this subject. At the beginning of the 1970s, a small number of Proclos siana eunomia females were released in a region where this glacial relict w as absent. We report here the genetic aspects of the evolution of the popul ations generated by these translocations. Both enzyme electrophoresis and w ing pattern morphometry disclosed a significant differentiation of the popu lations both with their mother population and within themselves. Field obse rvations and enzyme data suggest a stepping-stone colonization process, but there is no significant isolation by distance at this stage of population establishment, as predicted by Slatkin's 1993 model. Concerning phenotypic characters, there is a significant correlation between morphometric and geo graphical distances; this may be due to isolation by distance but the actio n of environmental gradients cannot be excluded. Our results show that this colonization, although induced with a low number of founders, was a succes s, despite a predicted loss of polymorphism.