Exposure to Predators Induces Phenotypic Plasticity in Cone Opsin Expression Profiles but not in Eye Size of Female Trinidad Guppies.

Teleost fish display very diverse visual systems through evolutionary adaptation and phenotypic plasticity to the variable light of aquatic environments. Whether predator presence influences eye size in prey is controversial because though larger eyes endow better optics, they also consume more energy and are more conspicuous. Moreover, whether predation alters the visual spectra of prey is unclear. Predation profoundly affects inter-populational divergence of male coloration and female mating preference in the Trinidad guppy (Poecilia reticulata). In this study, newborn guppies were raised under predation or control conditions, which revealed that although eye size did not differ between the treatments, predator presence induced plasticity in cone opsin expression profiles, potentially impacting female mate choice and predator sensitivity, as well as circumventing the costs of having large eyes. This study also lends support to the sensory drive model in guppy by evidencing how predation acts simultaneously on both male coloration and female visual spectra, reducing the survival of bright males, but also making them less attractive to females.