Bank Voles in Southern Eurasia: Vicariance and Adaptation

Phylogeographic lineages are interpreted as the
product of repeated isolation in glacial refugia, leading to vicariant
differentiation. Being restricted to a given geographic
area could also promote adaptive divergence in response to
local conditions. The role of phylogeny and climate in the
evolution of the bank vole (Myodes glareolus) was investigated
here, focusing on molar tooth shape, a morphological feature
related to the exploitation of food resources. A balanced
role of phylogeny and climate was demonstrated. Response to
environmental factors led to morphological convergence of
bank voles from different lineages living in similar environments,
and to within-lineage divergence in extreme environments.
An important interaction of climate and phylogeny was
found, suggesting that each lineage is living in a particular
environment. This lineage-specific adaptation to a range of
environmental conditions may have conditioned the potential
of post-glacial recolonization of each lineage. Morphological
covariation with environmental conditions further highlights
the potential of adaptation of this species.