Eastern Arc of Glacial Relict Species—Population Genetics of Violet Copper Lycaena helle Butterfly in East-Central Europe

We studied <i>Lycaena helle</i> (Lepidoptera: Lycaenidae) population genetics in lowlands and mountains of East-Central Europe using the microsatellite markers previously applied in population studies mainly in mountains of Western Europe. As in the West, the East-Central populations are genetically diverse (mean expected/observed heterozygosity 0.67/0.49), affected by drift processes (mean inbreeding coefficient 0.277) and widely differentiated (mean F_ST 0.209). The Polish lowland populations, all of them bivoltine in contrast to mountain populations, are less differentiated than Romanian populations, which are bivoltine in low and univoltine in high altitudes. The lowland Romanian population Vad is extremely genetically impoverished. A transferred CZ population from Western Europe is impoverished relative to its donor population, but the genetic parameters remain within a range of other studied so far. Dendrogram of allelic frequencies suggests that the populations form two branches, one rooted in southeastern Poland and branching towards Carpathians in Romania, one encompassing populations in central and northern Poland. We conclude that the lowland Romanian populations, plus populations in unglaciated southeastern Poland, represent sites where the species survived the glacial cycles in situ, comprising rear edge of subsequent upslope expansion, while northern Poland was colonised from more easterly regions.