Multivariate selection and intersexual genetic constraints in a wild bird population

When traits are genetically correlated between the sexes, the response to selection in one sex can be altered by indirect selection in the other sex, a type of genetic constraint commonly referred to as intralocus sexual conflict (ISC). While potentially common, ISC has rarely been studied in wild populations. In this study, we applied a multivariate framework to quantify the microevolutionary impacts of ISC over a set of morphological traits (wing length, tarsus length, bill depth, and bill length) in a wild population of great tits (Parus major) from Wytham Woods, UK. Specifically, we quantified the impact of cross-sex genetic covariances (the B matrix) on the additive genetic variance for relative fitness expected to be generated by directional selection and additive genetic (co)variance. Together, multivariate sex-specific selection and additive genetic (co)variance were expected to generate additive genetic variance for relative fitness that was uncorrelated between the sexes (cros...