Female scissortail sergeants (Pisces: Pomacentridae) use test eggs to choose good fathers

In species where males look after the offspring, females are under strong selection to adopt choice strategies that allow them to find good fathers. I investigated female choice strategies in the scissortail sergeant, Abudefduf sexfasciatus. In a manipulation experiment where the position of clutches was altered, some females laid small clutches to test males and only went back to males if the test eggs were cared for. Test eggs allowed females to select good fathers, whereas usual predictors of parental quality, such as male body size and courtship rates, seemed ineffective. However, test eggs were used only by 7.4% of females at the very beginning of the male's mating phase, probably because of the high cost of this strategy. When possible, females preferred to mate with already guarding males. By pooling eggs in nests that already contained the clutches of other females, they diluted the cost of predation and cannibalism by the parental male, and obtained higher hatching success for their broods.