SWANSON, BO; Northern Arizona University, : Comparison of fish feeding behaviors between laboratory and field: Do lab feeding analyses reflect ecologically important behaviors?

Analyses of the kinematics of feeding behaviors have elucidated the mechanisms integral to fish feeding. Previous studies have demonstrated that differences in motor pattern and morphology produce a wide variety feeding behaviors within and among fish species. In this study, we compare lab feeding kinematic studies with field behavioral observations and ask two questions. First, do laboratory feeding events reflect ecologically important feeding behaviors? Second, are there kinematic differences between lab and field feeding behaviors? To address these questions, we recorded underwater digital images of freely feeding cichlids at 240 fields per second; these feeding events involved a wide range of food types and microhabitats. We then recorded feeding events of the same species in glass aquaria, in the laboratory, using pellet fish food as the food type. We assessed the degree of behavioral variability in the two situations by examining the presence/absence and frequency of stereotyped feeding behaviors. We also measured kinematic variables from the digital images including gape, cranial rotation, hyoid depression, and timing variables related to these measurements. Preliminary results indicate that fish perform a large number of distinct behaviors in the field that are not observed in the lab. These behaviors may not occur in the lab because of the non-challenging food and the structurally simple aquarium environment. However, the most commonly observed field behaviors, for example slow- and fast-inertial suction feeding, are readily solicited in the lab. As we continue this research we will determine if the shared lab and field feeding behaviors differ kinematically. This comparison will be important for testing the ecological validity of laboratory feeding analyses in functional morphology.