Local Adaptation: Causal Agents of Selection and Adaptive Trait Divergence

Divergent selection across the landscape can favor the evolution of local adaptation in populations experiencing contrasting conditions. Local adaptation is widely observed in a diversity of taxa, yet we have a surprisingly limited understanding of the mechanisms that give rise to it. For instance, few have experimentally confirmed the biotic and abiotic variables that promote local adaptation, and fewer yet have identified the phenotypic targets of selection that mediate local adaptation. Here, we highlight critical gaps in our understanding of the process of local adaptation and discuss insights emerging from in-depth investigations of the agents of selection that drive local adaptation, the phenotypes they target, and the genetic basis of these phenotypes. We review historical and contemporary methods for assessing local adaptation, explore whether local adaptation manifests differently across life history, and evaluate constraints on local adaptation.

Automated summary

Divergent selection across the landscape can drive the evolution of local adaptation in populations adapting to different environments, but the mechanisms behind this process are not well understood. Despite the wide observation of local adaptation in various taxa, there is a lack of experimental confirmation on the factors promoting local adaptation and the phenotypic targets involved.