Genetic mechanisms and correlational selection structure trait variation in a coral snake mimic

Covariation among traits shapes both phenotypic evolution and ecological
interactions across space and time. However, rampant geographic variation
in the strength and direction of such correlations can be particularly
difficult to explain through generalized mechanisms. By integrating
population genomics, surveys of natural history collections, and
spatially-explicit analyses, we tested multiple drivers of trait
correlations in a coral snake mimic that exhibits remarkable polymorphism
in mimetic and non-mimetic color traits. We found that although such
traits co-occur extensively across space, correlations were best explained
by a mixture of genetic architecture and correlational selection, rather
than by any single mechanism. Our findings suggest that spatially-complex
trait distributions may be driven more by the simple interaction between
multiple processes than by complex variation in one mechanism alone. These
interactions are particularly important in mimicry systems, which
frequently generate striking geographic variation and genetic correlations
among color pattern traits.