Female response to male advertisement signals in lesser waxmoths showed substantial genetic variation, phenotypic plasticity across rearing environments, and genotype-by-environment interactions resulting in crossing reaction norms. These results represent two previously underemphasized means by which genetic variation may be maintained in sexually selected traits: genetic variation in female response to male traits, and variation in the selection acting on both males and females. Genotype-by-environment interactions and reaction norms that cross indicate that divergent selection may act on male and female sexual traits if the level of environmental change is high. The processes that contribute to the maintenance of genetic variation may thus also contribute to population differentiation.