z-logo
open-access-imgOpen Access
Color discrimination thresholds in a cichlid fish: Metriaclima benetos
Author(s) -
Daniel EscobarCamacho,
Michaela A. Taylor,
Karen L. Cheney,
Naomi F. Green,
N. Justin Marshall,
Karen L. Carleton
Publication year - 2019
Publication title -
journal of experimental biology
Language(s) - English
Resource type - Journals
eISSN - 1477-9145
pISSN - 0022-0949
DOI - 10.1242/jeb.201160
Subject(s) - cichlid , chromatic scale , color vision , fish <actinopterygii> , colored , achromatic lens , color space , color model , color discrimination , stimulus (psychology) , artificial intelligence , computer vision , psychology , communication , biology , optics , computer science , physics , cognitive psychology , fishery , materials science , image (mathematics) , composite material
Color vision is essential for animals as it allows them to detect, recognize and discriminate between colored objects. Studies analyzing color vision require an integrative approach, combining behavioral experiments, physiological models and quantitative analyses of photoreceptor stimulation. Here, we demonstrate, for the first time, the limits of chromatic discrimination in Metriaclima benetos, a rock-dwelling cichlid from Lake Malawi, using behavioral experiments and visual modeling. Fish were trained to discriminate between colored stimuli. Color discrimination thresholds were quantified by testing fish chromatic discrimination between the rewarded stimulus and distracter stimuli that varied in chromatic distance (ΔS). This was done under fluorescent lights alone and with additional violet lights. Our results provide two main outcomes. First, cichlid color discrimination thresholds correspond with predictions from the receptor noise limited (RNL) model but only if we assume a Weber fraction higher than the typical value of 5%. Second, cichlids may exhibit limited color constancy under certain lighting conditions as most individuals failed to discriminate colors when violet light was added. We further used the color discrimination thresholds obtained from these experiments to model color discrimination of actual fish-colors and backgrounds under natural lighting for Lake Malawi. We find that for M. benetos, blue is most chromatically contrasting against yellows and space-light, which might be important for discriminating male nuptial colorations and detecting males against the background. This study highlights the importance of lab-based behavioral experiments in understanding color vision and in parameterizing the assumptions of the RNL vision model for different species.

The content you want is available to Zendy users.

Already have an account? Click here to sign in.
Having issues? You can contact us here