Résumé
Populations often experience variable conditions, both in time and space.
Here we develop a novel theoretical framework to study the evolution of
migration under the influence of spatially and temporally variable
selection and genetic drift. First we examine when polymorphism is
maintained at a locus under heterogeneous selection, as a function of the
pattern of spatial heterogeneity and the migration rate. In a second step,
we study how levels of migration evolve under the joint action of kin
competition and local adaptation at a polymorphic locus. This analysis
reveals the existence of evolutionary bistability where a low or a high
migration rate may evolve depending on the initial conditions. Last, we
relax several assumptions regarding selection heterogeneity commonly made
in previous studies and explore the consequences of more complex spatial
and temporal patterns of variability in selection on the evolution of
migration. We found that small modifications in the pattern of
environmental heterogeneity may have dramatic effects on the evolution of
migration. This work highlights the importance of considering more general
scenarios of environmental heterogeneity when studying the evolution of
life history traits in ecologically complex settings.