Rafael S Marcondes

Connecting adaptive phenotypic variation to both its genetic and ecological bases is one of the central goals of evolutionary biology. Birds, due to their ease of study and solid base of existing knowledge, present an ideal clade in which to advance that goal. Bird color traits in particular have a long tradition of being at the forefront of conceptual advances in evolutionary biology. Combined with recent dramatic increases in our ability to generate and analyze large phenotypic, environmental and genetic datasets, this means currently we are in a better position than ever to connect the environment-phenotype and phenotype-genotype links for specific color traits in birds, illuminating evolutionary patterns and processes generalizable to other traits and clades. I review selected recent advances in that arena, highlighting the most successful approaches, and seeking to illuminate the research avenues most likely to be fruitful in the near future. At a macroevolutionary level, I discuss how correlative models have improved our understanding of Gloger’s rule, a classic ecological principle. But mechanistic, biologically-inspired models such as BM, OU and their extensions are better suited to quantitatively compare and assess evolutionary hypotheses, and have revealed important differences in the mode and tempo of color evolution across clades, sexes and body regions. At a microevolutionary scale, I describe how study systems with ongoing gene flow along environmental gradients, such as hybrid zones, are particularly conducive to address both the genetics and ecology of phenotypic evolution. I weigh the strengths and weaknesses of the two major approaches to detecting the genomic loci underpinning phenotypic variation in such systems: divergence scans and genome-wide association studies. Finally, I conclude by pointing out the importance of synthetic approaches that include environment, phenotype and genotype within the same framework, and I suggest ideas for developments in that direction.