Negotiations Over Parental 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 parents benefit from shifting the
burden of care to the other. Here, we tested alternative hypotheses for
how parents will negotiate offspring care using a wild population of
clownfish (Amphiprion percula). We experimentally handicapped parents by
fin-clipping the female in 23 groups, the male in 23 groups, and neither
parent in 23 groups and measured changes in indicators of female, male,
and pair 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 although
the handicap was effective, clownfish do not face the predicted “cost to
conflict” when one parent is handicapped. Together, these results test the
generality of theoretical predictions and uncover novel questions about
whether and how negotiations operate in systems where interests are
aligned.