Meeting Abstract
Animals have light detectors in tissues outside of eyes, called extraocular photoreceptors, for non-visual functions like circadian photoentrainment and photolocomotory responses. Light sensitivity is most commonly achieved by visual pigments formed from an opsin protein bound to a chromophore molecule. The eyes of the stomatopod crustacean, Neogonodactylus oerstedii, contain dozens of opsins which probably arose through gene duplication, but we previously reported that only four opsins are expressed in the cerebral ganglion, or brain, of N. oerstedii. We also reported that both sighted and blinded stomatopods respond to illumination by flipping, walking, and/or swimming and suggested that stomatopods probably have opsin-based extraocular photoreceptors. Light detection is an important sensory modality for stomatopods, so the presence, location, and physiology of extraocular light detectors in these arthropods may help us predict the function of these receptors. In other arthropods, the extraocular opsin location is related to its presumed non-visual function. In the red swamp crayfish, Procambarus clarkii, two opsins are expressed in nerve fibers extending from the brain to the site of well-characterized caudal photoreceptors that elicit leg movements. Here, we present our data localizing opsin expression within the brain of N. oerstedii by in situ hybridization, which informs future work exploring the possible electrophysiological photoresponses of these putative receptors.
