Differential predation on the two colour morphs of Nicaraguan Crater lake Midas cichlid fish: implications for the maintenance of its gold-dark polymorphism

摘要: Predation can play an important role in the evolution and maintenance of prey colour polymorphisms. Several factors are known to affect predator choice, including prey's relative abundance conspicuousness. In polymorphic species, predators often target most common or visible morphs. To test if choice explain why Midas cichlid fish more (gold) morph is also rare than inconspicuous dark morph, we conducted predation experiments using two differently coloured wax models Nicaraguan crater lakes. Contrary expectations, observed overall higher attack rate on much abundant, yet less conspicuous models, propose frequency-dependent as a potential explanation for this result. Interestingly, differed between different types predators. While avian were biased towards abundant colourful morphs, did not show strong bias. However, seemed vary with clarity water, rates gold went up water decreased. The differential morphs might impact both thus polymorphism. © 2014 Linnean Society London, Biological Journal Society, 2014, 112, 123–131.