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 this study, using the burying beetle Nicrophorus vespilloides, which breed on carcasses and exhibit biparental care pattern, we investigated the impacts of resource availability, intraspecific and interspecific competition on individual parental care and reproduction in males and females. We manipulated the resource availability for each breeding pair by providing either a large or a small mouse carcass. Furthermore, we constructed the presence of intraspecific and interspecific competition for pairs breeding on large carcasses, by introducing an additional, small pair of beetles and blowfly maggots Calliphora, respectively. We found that, compared with 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 beetles, both males and females of the focal pair increased their care, whereas in the presence of blowfly maggots, they decreased their 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 sexual conflict over parental care.