Cues of maternal condition influence offspring selfishness

The evolution of parent-offspring communication was mostly studied from the perspective of parents responding tobegging signals conveying information about offspring condition. Parents should respond to begging because of thedifferential fitness returns obtained from their investment in offspring that differ in condition. For analogous reasons,offspring should adjust their behavior to cues/signals of parental condition: parents that differ in condition pay differentialcosts of care and, hence, should provide different amounts of food. In this study, we experimentally tested in the Europeanearwig (Forficula auricularia) if cues of maternal condition affect offspring behavior in terms of sibling cannibalism. Weexperimentally manipulated female condition by providing them with different amounts of food, kept nymph conditionconstant, allowed for nymph exposure to chemical maternal cues over extended time, quantified nymph survival (deathsbeing due to cannibalism) and extracted and analyzed the females’ cuticular hydrocarbons (CHC). Nymph survival wassignificantly affected by chemical cues of maternal condition, and this effect depended on the timing of breeding. Cues ofpoor maternal condition enhanced nymph survival in early broods, but reduced nymph survival in late broods, and viceversa for cues of good condition. Furthermore, female condition affected the quantitative composition of their CHC profilewhich in turn predicted nymph survival patterns. Thus, earwig offspring are sensitive to chemical cues of maternal conditionand nymphs from early and late broods show opposite reactions to the same chemical cues. Together with former evidenceon maternal sensitivities to condition-dependent nymph chemical cues, our study shows context-dependent reciprocalinformation exchange about condition between earwig mothers and their offspring, potentially mediated by cuticularhydrocarbons.