Meeting Abstract

49.3  Thursday, Jan. 6  Effects of antennule morphology and flicking kinematics on flow and odor sampling by the freshwater crayfish, Procambarus clarkii NELSON, J.M.*; MELLON, DeF.; REIDENBACH, M.A.; Univ. of Virginia; Univ. of Virginia; Univ. of Virginia jmn9h@virginia.edu

An organism’s sense of smell and their behavior in response to specific odors is dictated by the fluid medium in which an organism lives and the odor landscape. One such sensory behavior is antennule flicking, common to all decapods and used to explore their environment through detection of chemicals contained in the surrounding ambient fluid. These antennules contain chemosensory hairs, called aesthetascs, that are arranged individually or within an array, and respond to chemical stimuli. Presumably, the antennules are flicked to break down fluid boundary layers that form around the hairs and allow for faster transport of odors to sensory cells. Little is known about the small-scale hydrodynamics surrounding aesthetascs of organisms which utilize flicking to assess prey, conspecific, or predator presence in an odor plume. While work has been conducted on the implications of antennule flicking for a few species, including lobsters, little is known about how aesthetasc arrangement impacts odor detection. The lateral antennular flagellum of freshwater crayfish, Procambarus clarkii contains both chemosensory and mechanosensory hairs that respond to odors and fluid flow, respectively. Direct measurements of the antennule flick/return sequence were recorded and dynamically scaled physical models were constructed to allow experimentation congruent with realistic motion of antennule flicking, while maintaining morphology consistent with that of live crayfishes’ olfactory antennules. Utilizing particle image velocimetry, the flow structure for vortex shedding, boundary layer thickness, and leakiness through the aesthetasc array was observed, and found to be impacted by the speed of the flick and spacing of aesthetascs.