Genetic structure of Proclossiana eunomia populations at the regional scale (Lepidoptera, nymphalidae)

Populations of Proclossiana eunomia (Lepidoptera, Nymphalidae) occur in middle Europe in patchy habitats of hay meadows along valleys or peat bogs. Samples of P. eunomia populations from the Ardennes region (northern France and southern Belgium) were analysed by allozyme electrophoresis. Patches isolated by more than 2 km of mature forests proved genetically distinct from their neighbouring populations. Mantel tests and regression analysis showed that the degree of genetic differentiation between the 26 studied populations is related to the geographical distances between them. Autocorrelation analysis (Moran's I ) showed that allele frequencies are positively correlated for populations up to 13 km apart and that the genetic neighbourhood of individuals is in the range of 0.9 km, which is in accordance with movement studies in this species conducted in the same area. Analysis using Wright's F-statistics revealed that the highest differentiation occurs between populations of the same subregion, whereas the whole Ardennes region is not genetically partitioned into subregions. This is probably because the connectivity of the network of suitable habitats has significantly weakened only since the 1950s, and thus subregional differentiation has not yet occurred.