Caenorhabditis elegans. (Photo credit: Serena Zhang)

Color perception is an important aspect of the way many organisms navigate their world. The ability to perceive color has thus far thought to depend on the presence of either eyes or minimally receptive cells containing opsin receptor genes. Ghosh et al. show that foraging Caenorhabditis elegans roundworms, which do not have eyes or opsins, can distinguish a blue color indicative of a toxin released by bacterial mats. They suggest that the worms do this through the detection of the ratio between blue and amber light, a process dependent on at least two cellular stress-response genes. Different strains of C. elegans responded to different ratios, suggesting that this pathway plays an ecological role.

Reference

Ghosh DD, Lee D, Jin X, Horvitz HR, Nitabach, MN. (2021). C. elegans discriminates colors to guide foraging. Science. 371, 1059-1063. DOI: 10.1126/science.abd3010