Julie Hufnagel How does odor sampling change as crayfish grow: High speed video studies of Orconectes immunis. Division Sciences Department Biology Year 2004 Advisor Kristina Mead

Crayfish can interpret their chemical environment by moving their antennules in rapid "flicks" which allow them to sample chemicals in the surrounding fluid. Specimens (N=40) of the local crayfish species Orconectes immunis were collected from Hebron Hatchery, a low-flow lake habitat.  Crayfish were collected over a large size range 28-78mm (rostrum-telson length).  Crayfish of different sizes were stimulated to flick using cat food pellet extract, and were filmed flicking in a special filming chamber using a high-speed digital video camera. The videos were captured using Dazzle MovieStarTM 5 program, and digitized using ImageJ 1.29x software. The variables that were analyzed included: antennule velocity, flick angle, and antennule structural parameters.  These measurements were used to calculate the Re (Reynolds number) describing the flick, the leakiness of flicks, and flow rate through bundles of hairs during flicks.  Larger crayfish had larger flick velocities, Re values, leakiness, and flow rate values.