Parental effects alter the adaptive value of an adult behavioural trait.

The parents' phenotype, or the environment they create for their young, can have long-lasting effects on their offspring, with profound evolutionary consequences. Yet, virtually no work has considered how such parental effects might change the adaptive value of behavioural traits expressed by offspring upon reaching adulthood. To address this problem, we combined experiments on burying beetles (Nicrophorus vespilloides) with theoretical modelling and focussed on one adult behavioural trait in particular: the supply of parental care. We manipulated the early-life environment and measured the fitness payoffs associated with the supply of parental care when larvae reached maturity. We found that (1) adults that received low levels of care as larvae were less successful at raising larger broods and suffered greater mortality as a result: they were low-quality parents. Furthermore, (2) high-quality males that raised offspring with low-quality females subsequently suffered greater mortality than brothers of equivalent quality, which reared larvae with higher quality females. Our analyses identify three general ways in which parental effects can change the adaptive value of an adult behavioural trait: by influencing the associated fitness benefits and costs; by consequently changing the evolutionary outcome of social interactions; and by modifying the evolutionarily stable expression of behavioural traits that are themselves parental effects.

We are very grateful to A Backhouse for maintaining the burying beetle colony and to K McGhee, N Boogert, M Schrader, I Baldwin, T Szekely, and C Bergstrom for their comments on early drafts of the manuscript. RMK was supported by a Wolfson Merit Award from the Royal Society; RMK and BJMJ were funded by an ERC Consolidators grant 310785 Baldwinian_Beetles to RMK; GB was funded by Marie Curie Intra-European Fellowship 252120 LIFHISBURBEE; JMH was funded by an Australian Postgraduate Award; O De G was funded CONACYT and by the Cambridge Trust.

This is the final version of the article. It first appeared from eLife via http://dx.doi.org/10.7554/eLife.07340.