RT Journal Article SR Electronic T1 C. elegans detect the color of pigmented food sources to guide foraging decisions JF bioRxiv FD Cold Spring Harbor Laboratory SP 092072 DO 10.1101/092072 A1 D. Dipon Ghosh A1 Xin Jin A1 Michael N. Nitabach YR 2016 UL http://biorxiv.org/content/early/2016/12/07/092072.abstract AB Here we establish that contrary to expectations, Caenorhabditis elegans nematode worms possess a color discrimination system despite lacking any opsin or other photoreceptor genes. We found that simulated daylight guides C. elegans foraging decisions with respect to harmful bacteria that secrete a blue pigment toxin. By absorbing yellow-orange light, this blue pigment toxin alters the color of light sensed by the worm, and thereby triggers an increase in avoidance of harmful bacteria. These studies thus establish the existence of a color detection system that is distinct from those of other animals. In addition, these studies reveal an unexpected contribution of microbial color display to visual ecology.One-sentence summary Color detection contributes to Caenorhabditis elegans behavioral ecology by guiding foraging decisions.