MEAD, K.S.; WILEY, M.B.: How Do Benthic Crustaceans Trace Odor Plumes In Waves?: Integrating Fine-Scale Odor Structure With Animal Behavior.

Like many crustaceans, stomatopods rely on their sense of smell to find food. Odors in their marine environment are present as filamentous plumes, which the animals have to trace to find the source. Stomatopods sample their chemical environment by flicking their antennules. We are studying stomatopod plume tracing strategies by simultaneously measuring the odorant concentration at their olfactory antennules and their searching behavior. We subjected stomatopods to environmentally relevant flow conditions (5 cm/s unidirectional flow, 2 cm/s +/- 5 cm/s wavy flow) in a flume with a meandering odor plume released from a momentumless source. The odor source consisted of mussel extract marked with rhodamine dye. Our novel approach uses Planar Light Induced Fluorescence to image two-dimensional cross-sections of the odor plume at the height of the animal’s antennules. The fluorescence intensity is directly proportional to the odorant concentration. We recorded fluorescence intensity with a 12-bit CCD camera positioned below the flume. The PLIF images show the concentration structures along the antennules and the concentration encountered as a function of time. In addition, we filmed stomatopods from above and from the side as they navigated up the odor plume. We measured animal direction, orientation, speed, turning rate, and path length to compare searching performance in unidirectional and wavy flow.