Allopaternal care in the fathead minnow, Pimephales promelas: stepfathers discriminate against their adopted eggs

Some species of fishes with exclusive male parental care exhibit the phenomena of allopaternal care and female preference for males with eggs. In these species, newly reproductive males adopt and care for the eggs of other males, apparently as a part of their mating strategy. Assuming that adoption is adaptive, I would expect males to discriminate between adopted eggs and eggs that they sired themselves. Specifically, I predicted that adopted eggs would receive less care and suffer heavier mortality than sired eggs. I examined the allocation of care and egg survival for adopted and sired eggs in the fathead minnow, Pimephales promelas, and corroborated both predictions.