Genetic diversity distribution among seasonal colonies of a nectar-feeding bat (Leptonycteris yerbabuenae) in the Baja California Peninsula

Gene flow and historical demography influence the level and distribution of population genetic variation. The nectar-feeding bat Leptonycteris yerbabuenae is a colonial and migratory species in tropical and subtropical regions of North America. We examined the distribution of genetic diversity among colonies of this species and assess whether a population in Baja California Peninsula shows signature of historical demographic change. We expected low genetic differentiation, because individuals are highly mobile and share mating sites. We also predicted a demographic signature consistent with past climatic fluctuations. During the spring maternity season, we sampled 120 individuals of six colonies along a 450 km transect in the Baja California Peninsula, Mexico. Individuals were genotyped with eight nuclear microsatellite loci and 1739 bp of two mitochondrial markers. We record weak but significant levels of nuclear structure and no mitochondrial differentiation among these colonies suggesting a high level of gene flow mediated by females. Genetic diversity estimation per colony and in the region was moderate, and consistent with previous studies. The mitochondrial data indicate that the population in the Baja California Peninsula experienced a demographic expansion during or after the late Pleistocene, probably related to the expansion of food resources. This is the first detailed genetic population study of L. yerbabuenae on the spatially disjunct part of its geographical range and it is the first record of a demographic expansion in a migratory nectar-feeding bat species from North America. Our results contribute to understanding the past demography and the natural history of this species in the Baja California Peninsula.