Female–female conflict is higher during periods of parental care in a group-living cichlid fish

Abstract

Parental care can be associated with novel or altered social relationships with conspecifics, yet little is known about how the broader structure of the social environment is modulated by individuals caring for dependent offspring. Here, we compared the social environments of breeding groups in which dependent offspring were either present or absent. We conducted a field study with Neolamprologus multifasciatus, a group-living cichlid fish endemic to Lake Tanganyika, in which females provide direct care for their offspring within a group's territory. We used two methods to characterize the social environments in each group: (1) behavioural scoring to quantify the interactions among all group members and (2) automated, computer-assisted, visual detection to track the movements of fish on their territories. We found that relative to groups without offspring, groups with dependent offspring showed heightened conflict among females, as well as appreciable contests between dominant males and noncaregiving females. Patterns of space use revealed that territories comprise distinct, female-held subterritories, and although caregiving females used wider spaces than noncaregiving females, their subterritory areas remained largely nonoverlapping. By combining two complementary approaches for characterizing the social environment we were able to show how periods of parental care can be associated with marked differences in the makeup of breeding groups' social environments.