Chemically Mediated Feeding Behavior in the

Chemoreception is the most widespread of the senses, and was the first one to evolve. This sense is known to influence a broad array of biological processes, with direct impacts on population and community structure. Perhaps the most obvious role of chemical signals, however, is in foraging behavior. Sensing surface bound or waterborne chemical cues aids in the search for and selection of food. Although gelatinous zooplankton predators form an integral and abundant part of the oceanic ecosystems, little is known about their chemoreceptive abilities. In this paper we report on chemoreception by the midwater hydromedusa, Mitrocoma cellularia. Our results demonstrate that this passive gelatinous predator exhibits a behavioral response to both olfactory (odor cloud) cues and taste (gel packets) signals. Such behavior can be correlated to the stereotypic reaction pattern displayed by the animals during normal feeding episodes. These results are the first definitive demonstration that a species of gelatinous zooplankton responds behaviorally to chemical cues