The role of indirect genetic effects in the evolution of interacting reproductive behaviors in the burying beetle, Nicrophorus vespilloides

Social interactions can give rise to indirect genetic effects (IGEs), which occur when genes expressed in one individual affect the phenotype of another individual. The evolutionary dynamics of traits can be altered when there are IGEs. Sex often involves indirect effects arising from first order (current) or second order (prior) social interactions, yet IGEs are infrequently quantified for reproductive behaviors. Here, we use experimental populations of burying beetles that have experienced bidirectional selection on mating rate to test for social plasticity and IGEs associated with focal males mating with a female either without (first order effect) or with (second order effect) prior exposure to a competitor, and resource defense behavior (first order effect). Additive IGEs were detected for mating rate arising from (first order) interactions with females. For resource defense behavior, a standard variance partitioning analysis provided no evidence of additive genetic variance – eith...