Variation in the Visual Habitat May Mediate the Maintenance of Color Polymorphism in a Poeciliid Fish

Abstract

The conspicuousness of animal signals is influenced by their contrast against the background. As such, signal conspicuousness will tend to vary in nature because habitats are composed of a mosaic of backgrounds. Variation in attractiveness could result in variation in conspecific mate choice and risk of predation, which, in turn, may create opportunities for balancing selection to maintain distinct polymorphisms. We quantified male coloration, the absorbance spectrum of visual pigments and the photic environment of Poecilia parae, a fish species with five distinct male color morphs: a drab (i.e., grey), a striped, and three colorful (i.e., blue, red and yellow) morphs. Then, using physiological models, we assessed how male color patterns can be perceived in their natural visual habitats by conspecific females and a common cichlid predator, Aequidens tetramerus. Our estimates of chromatic and luminance contrasts suggest that the three most colorful morphs were consistently the most conspicuous across all habitats. However, variation in the visual background resulted in variation in which morph was the most conspicuous to females at each locality. Likewise, the most colorful morphs were the most conspicuous morphs to cichlid predators. If females are able to discriminate between conspicuous prospective mates and those preferred males are also more vulnerable to predation, variable visual habitats could influence the direction and strength of natural and sexual selection, thereby allowing for the persistence of color polymorphisms in natural environments.

Developmental plasticity in vision and behavior may help guppies overcome increased turbidity

“…Additionally, the λp50 was calculated for each treatment when measuring light filtered through clear or turbid water to a depth of ~15 cm. The λp50 is the median wavelength of photons between 300 and 800 nm (McFarland and Munz 1975;Hurtado-Gonzales et al 2014). A difference in λp50 would indicate lighting environments were shifted toward longer (larger λp50) or shorter (lower λp50) wavelengths of light.…”

Differentiation of visual spectra and nuptial colorations of two Paratanakia himantegus subspecies (Cyprinoidea: Acheilognathidae) in response to the distinct photic conditions of their habitats

“…The light environment is a factor known to drive both the reception and production of visual signals of fishes (Hornsby et al 2013;Hurtado-Gonzales et al 2014;Shin and Choi 2014;Terai et al 2006;Tezuka et al 2014). Indeed, the present study showed that the spectral sensitivities of P. h. himantegus and P. h. chii are distinct: P. h. himantegus is more sensitive than P. h. chii to longer wavelength light, while it is less sensitive than P. h. chii at shorter wavelengths.…”

“…Variations in spectral sensitivity mainly result from the alternative usage of different opsin genes (Flamarique 2013;Johnson et al 2013;Kasagi et al 2015;Kondrashev et al 2013;Valen et al 2013). Furthermore, sexual selection favors individuals that can display visual signals that are readily distinguishable from the background (Hurtado-Gonzales et al 2014;Miyagi et al 2012;Morrongiello et al 2010;Selz et al 2014). Therefore, in addition to their link with visual properties, photic environments may also influence overall body coloration of fish.…”

The effects of commonly used anaesthetics on colour measurements across body regions in the poeciliid fish, Girardinus metallicus

“…Colour ornaments are particularly suited to being honest signals of quality (Zahavi, ) because they can be energetically costly to produce (Kodric‐Brown & Brown, ) and because they are often involved in complex trade‐offs among fitness‐enhancing functions (Cuthill et al ., ; Grether, ; Lozano, ). Poeciliid fishes are models for studying the relationship between coloration and behaviour (Hurtado‐Gonzales, Loew, & Uy ; Kolluru, ; Martin et al ., ). However, quantification of coloration traits in live poeciliids can pose challenges because the fish are so small.…”