Post-hatching parental care masks the effects of egg size on offspring fitness: a removal experiment on burying beetles

Parents can increase the fitness of their offspring by allocating nutrients to eggs and/or providing care for eggs and offspring. Although we have a good understanding of the adaptive significance of both egg size and parental care, remarkably little is known about the co-evolution of these two mechanisms for increasing offspring fitness. Here, we report a parental removal experiment on the burying beetle Nicrophorus vespilloides in which we test whether post-hatching parental care masks the effect of egg size on offspring fitness. As predicted, we found that the parent’s presence or absence had a strong main effect on larval body mass, while there was no detectable effect of egg size. Furthermore, egg size had a strong and positive effect on offspring body mass in the parent’s absence, while it had no effect on offspring body mass in the parent’s presence. These results support the suggestion that the stronger effect of post-hatching parental care on offspring growth masks the weaker e...