Parental effects on inbreeding depression in a beetle with obligate parental care

Inbreeding depression occurs when individuals who are closely related mate and produce offspring with reduced fitness. Although inbreeding depression is a genetic phenomenon, the magnitude of inbreeding depression can be influenced by environmental conditions and parental effects. In this study, we tested whether size-based parental effects influence the magnitude of inbreeding depression in an insect with elaborate and obligate parental care (the burying beetle, Nicrophorus orbicollis). We first tested for size-dependent maternal effects on offspring size using a phenotypic manipulation experiment where we created large and small adults by manipulating the amount of time they fed as larvae. Consistent with studies of other Nicrophorus species, we found that larger mothers produced larger offspring. We next tested for size-dependent parental effects on the magnitude of inbreeding depression in two traits: mean larval mass and survival from larval dispersal to eclosion. As in our first e..., ,