Dispersal of females and differentiation between populations of Epirrita autumnata (Lepidoptera : Geometridae) inferred from variation in mitochondrial DNA

Analysis of the, mitochondrial DNA (mtDNA) control region (CR) was used to examine the dispersal of females of a geometrid moth, Epirrita autumnata, in Fermoscandia. A 542-bp-portion of the CR of 200 individuals from four northern and four southern localities was sequenced. The mtDNA CR of E. autumnata contains a substantial amount of variation as a total of 108 mtDNA haplotypes were observed. Between the northern and the southern localities (similar to1100 km), there was a moderate level of genetic differentiation (F-ST = 0.128). The amount of variation in the mtDNA CR of E. autumnata was lower in the north than in the south. The reduction in genetic variability may result from a combination of historical bottlenecks that date back to the post-glacial recolonization of Fermoscandia and, present-day bottlenecks due to the northern E. autumnata populations experiencing repeated outbreaks followed by collapse in population size. On a small spatial scale (0.6-19 km), within the northern and southern areas, no genetic differentiation was detected suggesting ongoing gene flow due to the dispersal of E. autumnata females among the localities. This finding was contrary to our earlier expectation of poor flying ability of E. autumnata females.