Meeting Abstract
Animals vary greatly in color pattern and such patterns often play a role in speciation. Evolutionary biology aims to understand the selective mechanisms shaping color patterns and their perception by conspecifics and heterospecifics. Studies of color vision, the capacity to discriminate color regardless of brightness, are relevant for understanding coloration patterns, visual system sensitivities and visual signals. Combining data on photoreceptor spectral sensitivities, behavioral experiments and physiological models provides a unique opportunity to analyze chromatic discrimination in an integrative approach. Cichlids are some of the most colorful freshwater fishes. Their color patterns can be sexually dimorphic and are likely important for species recognition, mate choice, and speciation. Hence, accurate visual communication is essential for cichlid behavior. Here we demonstrate color vision of a rock-dwelling cichlid from Lake Malawi: Metriaclima benetos. We combine behavioral experiments through classical conditioning with physiological models in order to estimate the perceptual thresholds of color contrast. In our experiments we compared fish performance with predictions from an established color vision model, the receptor noise-limited model. Our study produced two main outcomes: First, we demonstrate that M. benetos possesses color vision. Fish were more likely to choose the trained stimuli over any distracters, irrespective of brightness. Second, we describe the color thresholds of their chromatic discrimination. Fish were able to discriminate more disparate colors but not more similar ones, allowing us to determine how photoreceptor noise affects color discrimination.
