MEAD, K. S.; Denison University, Granville OH: Physical Tuning: Does Antennule Morphology Correlate With The Hydrodynamics Of The Flow Environment In The Crayfish Orconectes virilis?

Through a variety of physical mechanisms and at several scales, the local flow environment affects the shape of waterborne chemical signals. For instance, waves, current, turbulence, and substrate roughness affect both the shape of the odor plume downstream of an odor source and the nature of the odor filaments within the plume. Since crayfish rely on these chemical signals to extract information about predators, prey, and mates, one might expect the chemical sensors (aesthetascs) on crayfish antennules to be physically tuned to the presentation of chemical cues by the flow environment. This hypothesis was tested by comparing antennule length and aesthetasc length, diameter, and spacing among several geographically and historically distinct populations of Orconectes virilis experiencing a variety of flow conditions. Several size classes of male and female animals from newly hatched animals to full-sized adults were analyzed from each population. Structural parameters were measured using Scion Image software on SEM micrographs, and analyses of variance were performed using StatView. Antennule and aesthetasc structural parameters were found to vary with animal size, sex, and flow environment.