Stronger net selection on males across animals

Sexual selection is considered the major driver for the evolution of manifold sex differences. However, the eco-evolutionary dynamics of sexual selection and their role for a population’s adaptive potential to respond to environmental change have only recently been explored. Theory predicts that sexual selection promotes adaptation at a low demographic cost only if net selection is stronger on males compared to females. We used a comparative approach to show that net selection is indeed stronger in males in species prone to intense sexual selection. Given that both sexes share the vast majority of their genes, our findings corroborate the notion that the genome is often confronted with a more stressful environment when expressed in males. Collectively, our study supports a long-standing key assumption required for sexual selection to bolster adaptation, and intense sexual selection may therefore enable some species to track environmental change more efficiently.