Ecological and social factors lead to variation in parental care between sexes in a burying beetle

Sexual conflict over parental care represents a divergence in the evolutionary interests between males and females, consequently leading to distinct sex roles in parental care and reproductive strategies. However, whether and how various ecological and social environments influence such sex differences remains largely unclear. In the present study, using the burying beetles Nicrophorus vespilloides, we experimentally investigated the impacts of resource availability and inter- and intra-specific competition pressure on individual parental care and reproduction in males and females. We manipulated the resource availability for the breeding pairs by providing them with either large or small mouse carcasses, and constructed the presence of intra- and inter-specific competition, by introducing an additional, small pair of beetles and blowfly maggots Calliphora, respectively. We expected that males would decrease their parental care, while females would increase theirs, in response to smaller carcass. We also expected that the presence of intra- and inter-specific competition differentially affected the cares of males and females. We found that, compared to males and females breeding on large carcasses, males did not change their care, whereas females increased their care, when breeding on small carcasses. In the presence of another pair of adults, both males and females increased their parental care, whereas in the presence of blowfly maggots they both decreased their parental care. Our results showed that males and females adjust their parental care based on resource availability and competition pressure, with sex-specific differences driven by ecological and social factors. Our study sheds light on the importance of sex-specific parental care in response to various external drivers which contributes to a better understanding of the evolution of sex conflict over parental care.