Meeting Abstract

40.5  Monday, Jan. 5  Changes in Wingstroke Kinematics Associated with an Increase in Swimming Speed in a Pteropod Mollusk, Clione limacina SZYMIK, Brett G*; SATTERLIE, Richard A; Eastern Connecticut State University; University of North Carolina Wilmington szymikb@easternct.edu

In order to produce useful movement, all locomotory systems must manage the interface between the body and the environment. This interaction is more pronounced in soft-bodied aquatic organisms whose bodies are easily deformed by their surroundings. Clione limacina is a pteropod mollusk (Gastropoda) that swims by rhythmically flapping two wing-like parapodia. Its swimming is akin to underwater flight. Much is known about the morphology of Clione as well as the neural origins and control of Cliones swimming behavior. Clione demonstrates two distinct swimming speeds, termed slow and fast swimming. Slow swimming is a constant behavior that Clione uses to maintain its position in the water column, while fast swimming is observed during hunting and escape. Clione has proven itself to be a trove of information regarding how oscillating locomotory neural networks behave. This study begins to address how those neural signals are translated into behaviors that produce meaningful movement. High speed videography and the direct linear transformation technique (DLT) were used to obtain three-dimensional data from multiple points on the animal’s body. Given its low-intermediate Reynolds number (generally < 200), alternative mechanisms of thrust generation that allow the animal to overcome drag are likely important to Clione. Its wings come closer to its body during fast swimming, virtually wrapping around the body in some animals. The wings also produce a sculling motion during wing reversal that is more prominent during fast swimming. These observations suggest a squeeze mechanism involving the wings and body that generates thrust during the recovery phase of the wingstroke, when the animal would otherwise be in a state of stall.