Intersexual attraction in natal root voles Microtus oeconomus

Summary

By an enclosure experiment we tested whether natal dispersing root voles Microtus oeconomus (Pallas 1776) were prevented from colonising already of habitat patches or if they were attracted to habitat patches by potential mates. The treatment consisted of manipulating the presence of animals in immigration patches, either with the presence of solitary sexuallymature male or female, whereas empty patches were used as control. Immigration patches were separated from a patch used to release a matriline (mother with her newly weaned litter) by a semipermeabel fence allowing only interpatch movements of young animals. We predicted that either a social fence would prevent immigration to treatment patches, or that potential mates would attract dispersing individuals. In particular we expected fewer dispersing males to colonise male occupied patches, and fewer dispersing females to colonise female occupied patches due to intersexual competition, ie an intrasexual social fence. We found that a higher proportion of females settled in male treatment patches than in female patc