FEMALE-BIASED DISPERSAL IN THE MONOGAMOUS MAMMAL CROCIDURA-RUSSULA - EVIDENCE FROM FIELD DATA AND MICROSATELLITE PATTERNS

We investigated dispersal patterns in the monogamous Crocidura russula , based both on direct field observations (mark-recapture data) and on genetic analyses (microsatellite loci). Natal dispersal was found to be low. Most juveniles settled within their natal territory or one imm ediately adjacent. Migration rate was estimated to two individuals per year and per population. The correlation between genetic and geograph ical distances over a 16 km transect implies that migration occurs ove r short ranges. Natal dispersal was restricted to first-litter juvenil es weaned in early May; this result suggests a direct dependence of di spersal on reproductive opportunities. Natal dispersal was highly fema le biased, a pattern unusual among mammals. Its association with monog amy provides support for the resource-competition model of dispersal. Our results demonstrate that a state-biased dispersal can be directly inferred from microsatellite genotype distributions, which opens new p erspectives for empirical studies in this area.