Meeting Abstract
38.6 Sunday, Jan. 5 09:15 Seeing double: the ontogeny of light sensitivity in stomatopod crustaceans FELLER, KD*; COHEN, JH; CRONIN, TW; University of Maryland Baltimore County kfeller1@umbc.edu
In addition to having unique adult visual systems, stomatopod crustaceans also undergo a unique process of eye development. Just prior to metamorphosis, an adult retina and associated neuropils emerge adjacent to the existing structures within each larval compound eye. The duration of this double-retina eye can range from as little as a few hours up to several days. The extent to which each retina contributes to the animal’s visual sensitivity is currently unknown. Each eye has the potential to gather visual information simultaneously from two retinas, or the larval retina could dominate the visual sensitivity until the adult structures are more completely developed in the postlarva, at which point the adult retina becomes the prevailing sensor. Previous findings using microspectrophotometry led us to hypothesize the latter scenario. To test this, we used electroretinography to simultaneously measure light sensitivity in both retinas throughout ontogeny in a Western Atlantic stomatopod species, Squilla empusa, which undergoes complete eye metamorphosis within a 24 hour period. We rejected our hypothesis by the finding of robust electroretinogram responses in both the larval retina and the adult retina from the very onset of its emergence in the terminal stage larva. These data show significant decreases in dynamic range and response latency as well as an increased sensitivity to light as the eyes shift from the single-retina, larval type to the double retina adult dominant eye. This sensitivity shift was likely due in part to a clear circadian rhythm in visual sensitivity where photoreceptors were more sensitive when tested during the night phase. These are the first data regarding the physiology of the unique eye development in stomatopods and are important for directing further physiological investigations of the system.
