Data from: Short-term variations in gene flow related to cyclic density fluctuations in the common vole

In highly fluctuating populations with complex social systems genetic
patterns are likely to vary in space and time due to demographic and
behavioural processes. Cyclic rodents are extreme examples of
demographically instable populations that often exhibit strong social
organisation. In such populations, kin structure and spacing behaviour may
vary with density fluctuations and impact both the composition and spatial
structure of genetic diversity. In this study, we analysed the multiannual
genetic structure of a cyclic rodent, Microtus arvalis, using a sample of
875 individuals trapped over three complete cycles (from 1999 to 2007) and
genotyped at 10 microsatellite loci. We tested the predictions that
genetic diversity and gene flow intensity vary with density fluctuations.
We found evidences for both spatial scale-dependant variations in genetic
diversity and higher gene flow during high density. Moreover,
investigation of sex-specific relatedness patterns revealed that, although
dispersal is biased toward males in this species, distances moved by both
sexes were lengthened during high density. Altogether, these results
suggest that an increase of migration with density allows to restore the
local loss of genetic diversity occurring during low density. We then
postulate that this change in migration results from local competition,
which enhances female colonisation of empty spaces and male dispersal
among colonies.