Sex differences in response to experimentally induced sexual conflict in Cinereous Tits Parus cinereus

Abstract

ABSTRACT Capsule The experimental removal of either the male or female from breeding pairs of Cinereous Tits Parus cinereus revealed that both sexes could increase their nestling provisioning rate to compensate fully for the loss. However, single females but not males delivered lower quality food. Aims Parents would benefit from transferring the burden of costly parental care onto their mates, which leads to sexual conflict. Here, we tested how each sex might change their investment when their partners were temporarily removed. Methods We used video recordings at nests of 24 pairs of Cinereous Tits to compare the nestling provisioning rate and prey quality of parents before, during and after the experimental, temporary removal of the other parent. Results Under biparental care, male and female parents had the same rate of food delivery to their broods, but females provided a higher proportion of higher quality food. When either parent was removed, the remaining parent increased their provisioning rate to equal that of the pair before the removal. However, while males increased the quality of food items to compensate for their removed females, females provisioned with lower quality food when their males were removed. Conclusions Our results suggest that males and females face different energetic costs when provisioning nestlings. We also show the importance of considering food quality, as well as food quantity, when considering parental care compensation that might arise as a result of sexual conflict.