The Heritability of Migration Behaviors in a Wide-Ranging Ungulate

Migration behavior is thought to be declining globally in the face of rapid human-mediated environmental change. Although many species exhibit individual plasticity in their migratory behavior, not all species demonstrate the level of plasticity necessary to adjust to novel conditions. Selection on heritable behaviors might therefore play an important role in the maintenance of migratory phenotypes for some species. Using GPS and genomic data from 143 individuals (151 animal-years) in a pedigree-free quantitative genetic approach, we estimated heritability, repeatability, and sources of environmental variation for migration traits in migrating mule deer (Odocoileus hemionus). We found low heritability and low repeatability for broad patterns of migration timing, and moderate heritability and repeatability for distance, duration, and movement rate along the migratory route. Our findings suggest that wild mule deer populations have the potential to respond to selection pressure generated by global environmental changes through microevolutionary changes in migration behaviors.