Investigating the population structure of Daubenton's bat in Europe : a multiple marker approach.

Zoonotic diseases are of increasing concern on a global scale. In order to understand how such diseases spread it is vital to elucidate dispersal patterns of their hosts. Daubenton's bat (Myotis daubentonii) is one of the major reservoirs of European bat lyssavirus type-II which is transmissible to humans as rabies. The spatial pattern of variation in X-linked and autosomal microsatellites plus mitochondrial sequence was investigated across M daubentonii populations in Britain and Europe. Using a multi-marker approach allowed the exploration of phylogeographic processes, contemporary gene flow, barriers to gene flow, patterns of sex-biased differentiation and an insight into variable mating success between males and females. Two mitochondrial clades were found in Europe that appeared to be consistent with the expansion of M daubentonii from at least two glacial refugia. This was corroborated by similar broad-scale patterns of variation using microsatellites. Differentiation was low for micro satellites over wide geographic areas. This implies that levels of geneflow among populations are high, but a pattern of isolation by distance suggests that M daubentonii populations are not panmictic at a Europe-wide scale. Contrasting high levels of mitochondrial differentiation indicate that female dispersal is more restricted than males, probably as a consequence of female philopatry and male dispersal to swarming sites. No significant features acting as barriers to dispersal or colonisation were detected, including the English Channel. The ratio of X:autosomal effective population size was 0.84; greater than neutral expectations would predict. Although a number of factors could explain this, higher variability in mating success resulting in a reduced male effective population size seems the most likely explanation. These results suggest that the potential for EBL V -2 to be transferred among Daubenton's colonies is high and that, as dispersal is male-biased, males may be more instrumental in EBL V -2 spread.