Comparison of genetic patterns between European and Asian populations of an endangered butterfly species

Less transformed and managed grassland habitats in Asia serve as a good frame of reference for studies on demographics and ecological situations of grassland species in Europe. In this study, using AFLPs (transposon insertion display), we compared the genetic structures of populations of the endangered and highly specialised scarce large blue (Phengaris teleius, Bergsträsser, 1779) butterfly from Europe (Germany, Poland, and Ukraine) and Asia (Siberia and Mongolia). There are no differences in levels of intra‐population genetic variability between European and Asian P. teleius populations. Nevertheless, we found significantly higher genetic differentiation (wider scattering) among European populations than among Asian populations. All examined Eurasian populations were admixed, except for those from the Bavarian region (Germany) where an atypical genetic structure was observed for P. teleius. Individual membership probabilities to a population were higher and more variable among European populations than among Asian populations. Comparison of genetic spatial structures revealed an isolation‐by‐distance effect in both European and Asian populations. Genetic autocorrelation analysis showed that significant dissimilarity among individuals first appeared at a distance of 1800 km at Asian sites, but at only 400 km at European sites. The observed P. teleius genetic structure reveals substantial differences in the quality of connectivity among European and Asian populations, which favour Asian populations. It suggests that differences between European and Asian P. teleius population genetic structures have the origin in differences in habitat structures, emphasising the impact of habitat fragmentation on animal movement in Europe. Intra‐population levels of genetic variation of Phengaris teleius are similar in Europe and Inner Asia. Populations from both of those super‐regions are admixed. European populations exhibit larger genetic population differentiation than populations in Inner Asia. Also, isolation‐by‐distance is significant in Europe and non‐significant in Asia. Genetic local structure among Asian individuals is three times larger than among European individuals. This indicates on stronger effects of isolation and habitat fragmentation in European populations.