Population genetic structure of serotine bats (Eptesicus serotinus) across Europe and implications for the potential spread of bat rabies (European bat lyssavirus EBLV-1)

Abstract

Understanding of the movements of species at multiple scales is essential to appreciate patterns of population connectivity and in some cases, the potential for pathogen transmission. The serotine bat (Eptesicus serotinus) is a common and widely distributed species in Europe where it frequently harbours European bat lyssavirus type 1 (EBLV-1), a virus causing rabies and transmissible to humans. In the United Kingdom, it is rare, with a distribution restricted to south of the country and so far the virus has never been found there. We investigated the genetic structure and gene flow of E. serotinus across the England and continental Europe. Greater genetic structuring was found in England compared with continental Europe. Nuclear data suggest a single population on the continent, although further work with more intensive sampling is required to confirm this, while mitochondrial sequences indicate an east-west substructure. In contrast, three distinct populations were found in England using microsatellite markers, and mitochondrial diversity was very low. Evidence of nuclear admixture indicated strong male-mediated gene flow among populations. Differences in connectivity could contribute to the high viral prevalence on the continent in contrast with the United Kingdom. Although the English Channel was previously thought to restrict gene flow, our data indicate relatively frequent movement from the continent to England highlighting the potential for movement of EBLV-1 into the United Kingdom.

Genetic structure and diversity of a rare woodland bat, Myotis bechsteinii: comparison of continental Europe and Britain

“…Although most British populations shared the same haplotype as continental bats, the southern populations had a unique haplotype that differed by a single base pair from the rest of Europe and Britain. Such differentiation agrees with results from the nuclear microsatellite data and similar differentiation has also been observed in E. serotinus (Moussy et al 2015). In the absence of clear physical barriers, the break observed may be linked to a lack of essential habitat, such as woodlands and potential swarming sites, which can limit the dispersal abilities of M. bechsteinii and further explain the separation between both populations.…”

“…Our finding of little diversity across the whole of Europe confirms a recent population range expansion which coincides with post-glacial colonisation as observed in multiple bat species (Moussy et al 2015;Petit et al 1999;van Schaik et al 2017). Kerth et al (2008) analysed the HV2 and ND1 mitochondrial genes of M. bechsteinii from the Balkans and suggested that this population may have been the unique glacial refugium for the species as genetic diversity was higher than in Europe.…”

“…Glacial refugia are prone to higher levels of genetic diversity than recently colonised areas. Multiple continental clusters have been identified for E. serotinus, M. myotis, R. ferrumequinum or B. barbastellus indicating the recolonization of Europe from separate refugia (Moussy et al 2015;Rebelo et al 2012;Rossiter et al 2000;Ruedi et al 2008). Although our study lacks samples from the Balkans, it confirms that Italy and Spain were unlikely ancient glacial refugia for the species as they mainly share the same haplotype as the rest of Europe (Kerth et al 2008).…”

“…Bechstein's bats sampled on the Isle of Wight, located off the British coast, did not show any differentiation compared with the rest of Britain (at K = 2); in contrast to the patterns observed for E. serotinus (Moussy et al 2015). Although M. bechsteinii forage over much shorter distances than E. serotinus (Catto et al 1996;Dietz and Pir 2011), it appears that they will more readily cross short distances of open water.…”

“…Myotis daubentonii (Atterby et al 2010), Plecotus austriacus (Razgour et al 2013) and Eptesicus serotinus (Moussy et al 2015). Bechstein's bats sampled on the Isle of Wight, located off the British coast, did not show any differentiation compared with the rest of Britain (at K = 2); in contrast to the patterns observed for E. serotinus (Moussy et al 2015).…”