Seasonal camouflage as a model to understand the scope for rapid adaptation in a changing world

Marcela Maki Alvarenga, Cynthia Ulbing, Inês Miranda, Mafalda S. Ferreira, Paulo Célio Alves, L. Scott Mills, João Pimenta, Jeffrey M. Good, José Melo-Ferreira

Human-driven environmental change is reshaping ecosystems and challenging species’ ability to adapt. Understanding how genetic variation enables adaptation is crucial for conservation and requires exemplary systems to test hypotheses and make predictions. One particularly suitable model for studying climate-driven adaptation is seasonal color change (SCC), a phenological trait in which individuals transition between summer-dark and winter-white pelage/plumage to maintain camouflage. This review evaluates SCC as a model for predicting adaptive responses to climate change. First, we address the vulnerability of phenological traits to climate change, due to their dependence on photoperiodic cues and complex molecular regulation. Second, we review SCC literature across all 21 SCC species, summarizing knowledge on its regulation, the fitness costs of mismatch induced by snow loss, and the limited role of plasticity in buffering these effects. Third, we review recent findings on the genetic basis of SCC polymorphism that have linked adaptation to selection on pigmentation alleles with multiple evolutionary origins (including introgression and de novo mutations). Finally, we discuss the implications of the genetic architecture of SCC polymorphism for evolutionary rescue and conservation strategies, as well as methods for testing adaptation conditions using modeling approaches. While past research on SCC already showcased how predictive evolution can be incorporated into conservation action, we identify research gaps, including limited fitness data, taxonomic biases, and the need for real-time ecological and genomic monitoring. Addressing these gaps will improve the accuracy of predictive models and the success of management strategies aiming at protecting species’ resilience to rapid environmental change.