Does specialisation affect genetic diversity in (pre-)Alpine populations of four species of Copper butterflies?

Genetic diversity is of crucial importance for population fitness and the potential of populations to adapt to environmental change. Population-level genetic diversity is expected to be reduced in specialists having small and isolated populations. We analysed genetic structure and diversity in (pre-)Alpine populations of four Copper butterfly species, differing in the degree of habitat specialisation. Despite substantial variation among genetic markers and molecular indices, genetic diversity and thus evolutionary potential tended to be highest in Lycaena hippothoe and lowest in L. tityrus. Microsatellite analyses revealed that genetic diversity tended to be higher in L. hippothoe and L. virgaureae than in L. helle and L. tityrus . MDH sequencing indicated only few differences among species, while GAPDH sequencing showed higher genetic diversity in L. hippothoe and L. tityrus than in L. virgaureae and L. helle . In L. helle , populations showed strong genetic differentiation but without clear spatial structure, while the other species showed genetic differentiation among clusters according to cardinal directions. These results do not match our a priori predictions of a high genetic diversity in L. tityrus and a particularly low one in the glacial relict L. helle . We thus document that evolutionary potential is not necessarily constrained in relict taxa, and that predicting genetic diversity is challenging. Implications for insect conservation Conservation status does not necessarily reflect genetic diversity at the species level. It thus seems to be more meaningful to focus on specific populations of concern to assess genetic vulnerability to environmental change.