Photoreception and the Role of Serotonin in the Photobehaviors of Amphipods

Intricate adaptations to visual systems have allowed amphipods to thrive in extreme habitats like caves. Photoreception is required for vision, hormone stimulation and photobehavior, and serotonin, a neurotransmitter modulated by light exposure, plays a vital role in many physiological processes like escape, reproduction, and feeding. Serotonin function can be altered by anthropogenic contaminants in the environment like antidepressants. The purpose of this study is to examine photoreception in Amphipoda and assess the impact of altered serotonin pathways on photobehavior. Using a preference assay, the photobehaviors of 3 species of subterranean and surface amphipods were determined before and after exposure to the antidepressant Fluoxetine. Results reveal photopreference varies with wavelength for certain cave species. The magnitude of overall phototactic response varied among all populations indicating this behavior is highly adaptable. Results also suggest that serotonin is intricately tied to photopreference and may be easily disrupted by Fluoxetine exposure.