Negotiations over offspring care: a test of alternative hypotheses in the clown anemonefish

In species with biparental care, conflict arises over how much each parent provides to their offspring because both benefit from shifting the burden of care to the other. Here, we tested alternative models for how parents negotiate offspring care using a wild population of clownfish (Amphiprion percula). Using 60 breeding groups, we experimentally handicapped parents by fin-clipping the female in 20 groups, the male in 20 groups, and neither parent in 20 groups and measured changes in female, male, and pair combined effort in response to handicapping. First, we found that handicapping resulted in a decrease in the number of eggs laid by fin-clipped females and a decrease in the amount of parental care by fin-clipped males. Second, contrary to predictions, female effort did not change in response to the male being handicapped, or vice versa. Finally, the number of embryos that matured to hatching, an indicator of pair effort, was not influenced by the manipulation, suggesting that althou...