Red vision in animals is broadly associated with lighting environment but not types of visual task

Abstract

Red sensitivity is the exception rather than the norm in most animal groups. Among species with red sensitivity, there is substantial variation in the peak wavelength sensitivity (λmax) of the long wavelength sensitive (LWS) photoreceptor. It is unclear whether this variation can be explained by visual tuning to the light environment or to visual tasks such as signalling or foraging. Here, we examine long wavelength sensitivity across a broad range of taxa showing diversity in LWS photoreceptor λmax: insects, crustaceans, arachnids, amphibians, reptiles, fish, sharks and rays. We collated a list of 161 species with physiological evidence for a photoreceptor sensitive to red wavelengths (i.e...