Rapid adjustment of cone opsin expression profiles may help Western mosquitofish (Gambusia affinis) maintain foraging efficiency in distinct light environments

Vertebrates rely on two special groups of photoreceptor cells (rods and cones) in the retina to receive visual information. Five opsin families in the outer segment of cone cells endow fishes with color vision. Fishes encounter diverse light environments in water (various light wavelengths and intensities), so they have evolved differing numbers and amino acid compositions of cone opsin genes and, in some, phenotypic plasticity in their expression profiles to quickly adjust to new light environments. However, clear evidence for a correlation between phenotypic plasticity in cone opsin expression and adaptation is lacking. The Western mosquitofish is a highly invasive species that colonizes diverse habitats. Here, by quantifying cone opsin expression levels of individuals experiencing distinct light conditions at different developmental stages, I show that the cone opsin expression profile of juvenile and adult Western mosquitofish can quickly react to altered photic properties. Moreover, a predation experiment also demonstrates that Western mosquitofish can maintain foraging efficiency under distinct light environments. Thus, phenotypic plasticity in cone opsin expression profiles may represent a crucial trait by which Western mosquitofish successfully colonize such a wide range of aquatic habitats.

Automated summary

Vertebrates rely on rods and cones in the retina for visual information. Fishes have evolved different numbers and amino acid compositions of cone opsin genes and show phenotypic plasticity in their expression profiles to adapt to diverse light environments. The Western mosquitofish demonstrates quick reactions in cone opsin expression to altered photic properties and is able to maintain foraging efficiency under distinct light environments. The phenotypic plasticity in cone opsin expression profiles may explain the successful colonization of a wide range of aquatic habitats by Western mosquitofish.