Résumé
Aim In this study, we analyse microevolutionary processes in common voles (Microtus arvalis) through the investigation of tooth morphological structure, in order to assess the relative impact of climate and phylogeographical history. Microevolutionary studies have shown that climate change may play a role in both population phylogeography and phenotypic differentiation. However, relatively little is known about the precise relationship between phylogeography and phenotypic variability and about how organisms respond to climate change. Location France, from sea level to the Alps (5 to > 2300 m a.s.l.). Methods This morphological analysis is based on first lower molar measurements from 16 geographically distinct common vole populations. Size and shape components are assessed separately. Population structure patterns are characterized using canonical variate analysis. We use phylogenetic analyses of two regions of mitochondrial DNA (the control region and the cytochrome b gene) to infer genetic structure. We calculate climate parameters from temperature and precipitation data. We investigate the influence of climate, geography and phylogeographical history on the phenotype using (1) multiple regression tests, (2) pairwise comparison of observation-by-variable matrices, and (3) a correlation method designed to compare three matrices. Results All populations were clearly structured, whatever the dataset. Neither size nor shape variation was correlated with climate parameters, but tooth shape was strongly correlated with both genetic structure and geographical distance. Main conclusions In French Microtus arvalis populations, molar shape differentiation is clearly associated with both phylogeographical history and geographical distance. Population phylogeographical history has a greater relevance than climate in accounting for variation in tooth morphology.