Genetic variation in parental effects contributes to the evolutionary potential of prey responses to predation risk

Despite the ubiquity of parental effects and their potential effect on evolutionary dynamics, their contribution to the evolution of predator-prey interactions remains poorly understood. Using quantitative genetics, here we demonstrate that parental effects substantially contribute to the evolutionary potential of larval antipredator responses in a leaf beetle (Leptinotarsa decemlineata). Previous research showed that larger L. decemlineata larvae elicit stronger antipredator responses, and mothers perceiving predators improved offspring responses by increasing intraclutch cannibal-ism—an extreme form of offspring provisioning. We now report substantial additive genetic variation underlying maternal ability to induce intraclutch cannibalism, indicating the potential of this adaptive maternal effect to evolve by natural selection. We also show that paternal size, a heritable trait, affected larval responses to predation risk but that larval responses themselves had little additive genetic variation. Together, these results demonstrate how larval responses to predation risk can evolve via two types of parental effects, both of which provide indirect sources of genetic variation for offspring traits.