Parity predicts allonursing in a cooperative breeder

Abstract

In some mammals that breed cooperatively, nonbreeding female helpers nurse offspring born to the breeding female in their group, a process known as allonursing. Previous laboratory studies have suggested that primiparous and multiparous females (those that have successfully given birth once or more, respectively) are more likely to contribute to allonursing than nulliparous females (those that have not given birth). In contrast, few field studies have been able to demonstrate whether breeding experience, or parity, affects the likelihood or duration of allonursing. In this study, we investigated whether the likelihood and duration of allonursing by subordinate female meerkats (Suricata suricatta) were associated with variations in their parity (number of pregnancies reaching a viable gestational age) and their immediate pregnancy status. Comparisons showed that nonpregnant nulliparous females were less likely to allonurse than nonpregnant primiparous and multiparous females, although parity was not related to variation in allonursing duration. Parity may enhance the expression of maternal behavior when exposed to foster pups, especially since mammary gland development has been shown to be directly associated with parity in other mammals.