Interspecific hybridization can generate functional novelty in cichlid fish

The role of interspecific hybridization in evolution is still being debated. Interspecific hybridization has on the one hand been suggested to facilitate the evolution of ecological novelty and hence the invasion of new niches and adaptive radiation when ecological opportunity is present beyond the parental species niches. On the other hand, hybrids between two ecologically divergent species may perform less well than parental species in their respective niches because hybrids would be intermediate in performance in both niches. The evolutionary consequences of hybridization may hence be context-dependent, depending on whether additional ecological opportunities do or do not exist. Surprisingly, these complementary predictions may never have been tested in the same experiment in animals. To do so, we investigate if hybrids between ecologically distinct cichlid species perform less well than the parental types when feeding on food either parental species are adapted to, and if the same h...