Helping opportunities and space segregation in cooperatively breeding cichlids

Studies of cooperative breeding have largely ignored the roleof conflict among helpers and how it shapes group dynamics andhelping behavior. In the present study, performing laboratoryexperiments with cooperatively breeding cichlids from Lake Tanganyika,we show that secondary group members (potential helpers) occupyhome ranges within the group territory and may be aggressiveto one another. Experimental removal of secondary group membersallowed the individual next in rank to move closer to the removedindividual's home range. In the field, dominant secondary groupmembers stayed closer to the brood chamber than did subordinategroup members of similar size, and proximity to the brood chamberwas related to the length of time spent inside. We suggest thatspace segregation and competition among secondary group membersis common in these cichlids, and may limit the opportunitiesto provide help.