Filial cannibalism in spottail darters (Etheostoma squamiceps) includes the targeted removal of infected eggs

摘要

In many species of fishes in which males guard their eggs, they also eat some of those eggs (filial cannibalism). One possible explanation for this behavior in freshwater fishes is that males are consuming eggs that have become infected with water mold, reducing its spread to other eggs. This hypothesis predicts that (1) egg loss due to infection is potentially significant if not controlled and (2) egg-guarding males can detect and target infected eggs for consumption. I confirmed both of these predictions in laboratory experiments using the spottail darter, a freshwater fish found in midwestern North America. This result supports an adaptive explanation for filial cannibalism, a seemingly nonadaptive behavior.