Use of forest corridors by boreal Xestia moths.

We studied movements of the noctuid moths Xestia speciosa and X. fennica in a fragmented forest landscape including old-growth spruce forest corridors in eastern Finland. We individually marked and released 1,796 adults of the habitat generalist X. speciosa and 683 individuals of X. fennica, which prefers old-growth spruce forests. Moths were recaptured with 60 sugar-bait traps that were placed within habitat corridors, in the non-habitat matrix and in surrounding old-growth forest patches. Both species favoured the corridors during their movements and tended to avoid entering the matrix. We analysed recapture rates and movements of the recaptured moths. Results suggest that X. speciosa moves longer distances than X. fennica. Though corridors clearly canalized movements by both species, the impact of old-growth forest corridors at the larger landscape scale was less clear in X. fennica. Movement behaviour of the two sexes differed more than that of the two species.