UV wavelengths experienced during development affect larval newt visual sensitivity and predation efficiency

Abstract

We experimentally investigated the influence of developmental plasticity of ultraviolet (UV) visual sensitivity on predation efficiency of the larval smooth newt, Lissotriton vulgaris. We quantified expression of SWS1 opsin gene (UV-sensitive protein of photoreceptor cells) in the retinas of individuals who had developed in the presence (UVþ) or absence (UV2) of UV light (developmental treatments), and tested their predation efficiency under UVþ and UV2 light (testing treatments). We found that both SWS1 opsin expression and predation efficiency were significantly reduced in the UV2 developmental group. Larvae in the UV2 testing environment displayed consistently lower predation efficiency regardless of their developmental treatment. These results prove for the first time, we believe, functional UV vision and developmental plasticity of UV sensitivity in an amphibian at the larval stage. They also demonstrate that UV wavelengths enhance predation efficiency and suggest that the magnitude of the behavioural response depends on retinal properties induced by the developmental lighting environment.

Differential Survival between Visual Environments Supports a Role of Divergent Sensory Drive in Cichlid Fish Speciation

“…Possibly, fish were less efficient at detecting and capturing food in unfavorable light regimes. Effects of spectral conditions on foraging performance have been documented in a variety of aquatic organisms (e.g., newts [Martin et al 2016], killifish , stickleback [Rick et al 2012], guppies [White et al 2005]). In addition, unfavorable light conditions can be stressful to fish (Volpato and Barreto 2001;Migaud et al 2007;Karakatsouli et al 2015) and exert species-specific effects on aggression levels (Holtby and Bothwell 2008;Carvalho et al 2013).…”

Habitat‐related variation in the plasticity of a UV‐sensitive photoreceptor over a small spatial scale in the palmate newt

“…The deprivation of UV radiation decreased the expression of SWS1 in larvae from agricultural habitats. We already observed a similar pattern for SWS1 in Lissotriton vulgaris larvae (Martin et al ., ) which originated from an agricultural pond, a typical habitat for that species in the western part of its range. In contrast, no change in the reaction norm of SWS1 opsin expression was detected in forest populations of L. helveticus .…”

“…We showed that the variation of the reaction norm of one component of the visual system, SWS1 opsin, depended on the optical characteristics (the transmission of specific wavelengths) of the larval environment and on the parental habitat. Plasticity in opsin expression has been observed in insects (Everett ), fish (Fuller et al ., ), amphibians (Martin et al ., ) and mammals (Hu ). This phenomenon may be widespread among animal groups.…”

“…The main sensitivity peak of LWS lies beyond 500 nm so that its expression is expected not to be altered by the treatments. We used the same protocol as in a previous study (Martin et al ., ). Briefly, the whole eyes were immediately frozen in liquid nitrogen and stored at −80 °C until RNA extraction.…”

“…Hence, the lack of exposure to specific wavelengths during development can strongly reduce the expression of the photoreceptor (opsin) sensitive to this wavelength range and alter the neural structure of the visual system (Wagner & Kröger, ). It has been shown that the expression of the UV‐sensitive photoreceptor (SWS1 opsin) depends on UV availability in the environment experienced during development in fish (Fuller et al ., ) and amphibians (Martin et al ., ). Whether and how environmental heterogeneity affects the plasticity of the visual system at the population level is still a largely pending issue.…”