Meeting Abstract

74.7  Sunday, Jan. 6  Scallop TV: Function and evolution of vision in Pectinidae SPEISER, D. I.*; JOHNSEN, S.; Duke University; Duke University dis4@duke.edu

Scallops� eyes are abundant in number and positioned along the mantle at the edges of the valves. These eyes are known to form relatively high-resolution images, but the possible functions of scallop vision remain open to debate. By placing specimens of the Common Bay Scallop Argopecten irradians in an operating flow tank, showing them simulated images of moving particles, and recording their behavior, we tested whether visual cues may influence feeding behavior in these animals. We found that scallops opened their mantles significantly more often (P<0.01) when shown large virtual particles (1.5 mm diameter, angular size of 1.7�) than when shown smaller particles (0.6 mm, 0.7�) or no particles at all. We also found that scallops opened their mantles significantly more often (P<0.01) when shown virtual particles moving at low speeds (2.5 and 5 cm/s) than when shown particles moving at high speeds (10 cm/s). Because mantle gape correlates positively with feeding rate in bivalves, our findings suggest that scallops may visually detect the presence and speed of moving particles and use this information to identify optimum feeding conditions. In a further investigation of scallop vision, we compared eye anatomy across a range of scallop species via conventional and confocal microscopy. Our findings suggest that visual resolution and sensitivity vary between scallop species and that these differences may correlate with ecological factors, such as substrate composition and levels of particle flux, inherent to the these species� environments.