Wavelength-specific swimming behavior of the starlet sea anemone, Nematostella vectensis
The starlet sea anemone, Nematostella vectensis, is part of the group Cnidaria. Cnidaria is sister to Bilateria (the group that includes vertebrates). N. vectensis is eyeless but contains 29 opsin genes and proteins which are necessary for light perception. By comparison, humans only have 4 which are found in the rods and cones. By understanding the function of these opsins we can elucidate the evolution of the complex eye. The planula larval stage is the dispersal stage for N. vectensis where it exhibits substrate seeking behavior and uses light cues to find a suitable environment. In this experiment we studied wavelength-specific behaviors of N. vectensis. We subjected anemone larvae to UV light and specific colors of light within the visual spectrum. Videos of behavior were recorded under infrared light. Data was analyzed using Trackmate in FIJI software to determine the percentage of larvae swimming in each frame. This was used to characterize the swimming behavior in response to light. At short wavelengths (315 - 420) larvae swam up in the column. At long wavelengths, larvae swam down in the column (>420 - 625). At approximately 650-700 larvae were less responsive to light and behavior was indistinguishable from dark. I am currently working on genotype larvae with an opsin gene knockout. In the future, I will use knockout larvae to determine the function of this opsin protein in larval swimming behavior.