No enforcement of cooperation in a group-living parrot

What is it about?

The question whether breeders in the endangered El Oro parakeet can use aggression to force subordinate helpers to care for the breeder's offspring. +++++++++++++ In cooperatively breeding species, in which non-breeding helpers assist in rearing the offspring of breeding individuals, conflicts of interest commonly occur between breeders and helpers over their respective contributions to offspring care. During such conflicts, breeders might use aggressive behavior to enforce contributions of helpers to offspring care, especially if helpers are not related to the breeders and their offspring and thus do not stand to gain indirect fitness benefits by helping. Using a combination of behavioral and genetic data, we investigated in the cooperatively breeding El Oro parakeet Pyrrhura orcesi (i) whether breeders are dominant over helpers, (ii) whether they use aggressive behavior toward helpers to enforce offspring provisioning, and (iii) whether the relatedness of helpers to the nestlings affects the frequency of—or the reaction of helpers to—such aggressions. Even though breeders were generally dominant over helpers, we found no evidence for the enforcement of alloparental care. This finding was independent of the relatedness between helpers and nestlings, even though distantly related helpers overall contributed little to offspring care. We suggest that the inability of breeders to properly assess the work rates of their helpers at least partly explains the absence of enforcement.

Featured Image

Why is it important?

Enforcement has been suggested as key mechanism in the evolution of alloparental care. However, evidence for enforced help is as yet scarce. Our results add to a growing body of evidence suggesting that enforcement might be an exceptional rather than a general mechanism underlying the expression of alloparental care in cooperatively breeding species.