Biparental division of roles in the convict cichlid fish: influence of intruder numbers and locations

Abstract

The convict cichlid fish (Archocentrus nigrofasciatus) has a parental division of roles in which the male spends much of his time defending the territory while the female remains near to the offspring. This division is not obligate because both parents do switch roles for brief periods and, in the absence of the mate, both sexes will perform all roles. We predicted that the division of roles depended on each parent being able to successfully complete its task. If a task could not be completed by a single parent, role specializations would be reduced resulting in a division of labor. That is, both parents would perform the same task. We modified the relative importance of the defensive role by changing the number and location of conspecific intruders. When we increased the number of distant intruders from one to two, we found that the division of roles was unaffected. Neither parent increased its defensive activities, although they did attack both intruders. Furthermore, when females did attack an intruder, it was usually the same intruder being attacked by the male. This too resembled pairs attacking single intruders. We concluded that, for distant intruders, both sexes seemed to invest a fixed amount in protecting the territory and the division of roles remained unchanged when intruder numbers changed. Placing one intruder near to the offspring greatly escalated the amount of time both parents spent attacking the intruder resulting in less time either parent spent near the offspring. A second intruder placed at a greater distance to the offspring was largely ignored by both parents. We believe we succeeded in modifying the division of roles by increasing the importance of one parental task and, in this way, the parental care in the convict cichlid resembled a division of labor around a single task.