INBREEDING AVOIDANCE INCREASES DISPERSAL MOVEMENTS OF THE MEADOW VOLE

This study tested whether inbreeding avoidance could influence the frequency and timing of dispersal movements in a small microtine rodent, the meadow vole (Microtus pennsylvanicus). Meadow voles released into experimental grassland plots with siblings were more likely to disperse from these plots than were voles released into similar plots with nonsiblings. Furthermore, voles that dispersed from sibling groups did so sooner than dispersing voles from nonsibling groups. Voles released with nonsiblings were recaptured within the plots for longer periods than were voles from sibling groups. Males from both groups remained within the plots for shorter times than did females, but the degree of this sex bias was greater for sibling groups. Thus, it appears that inbreeding avoidance can influence dispersal movements of the meadow vole and may be partially responsible for patterns of male-biased dispersal in at least some mammals.