CHEROSKE, AG; CRONIN, TW; University of Maryland, Baltimore County; University of Maryland, Baltimore County: Phenoptypically plastic color vision in a stomatopod crustacean and its potential effects on color signaling in variable light environments.

Many animals have color vision systems that seem well-suited to their local environment. Changes in color vision can occur over long periods (evolutionary time), or over relatively short periods such as during ontogeny. A select few animals are able to visually acclimate solely in response to varying environmental stimuli. Many stomatopod species occur over a wide range of depths (<1 m � 30m) where the corresponding spectrum and intensity of ambient light varies. Over 10-12 weeks, post-larvae of certain species can �tune� their spectral sensitivities using filters within specialized photoreceptors in response to photic changes. To determine if tunable color vision also occurs in adult stomatopods, individuals (Gonodactylus smithii) were collected intertidally and maintained in aquaria with either shallow �white� or deep �blue� lighting for three months. Afterwards, spectral changes in intrarhabdomal filters were assessed using microspectrophotometry. Animals in blue light had spectral sensitivities that were short-wavelength shifted by 5-10 nm compared to those in white light. These data were combined with spectral reflectances of prominent body spots and relevant irradiance measurements in a chromaticity model to estimate how well color signals are �perceived� in different environments. Results from the model indicate that the various colored body spots are perceived similarly regardless of changes in photic environment. These data suggest that stomatopods have a tunable color signaling system that is phenotypically plastic at any life stage and that effectively increases sensory function in a variety of habitats.