Multimodal integration in the feeding behaviors of predatory teleost fishes

The search for useful model systems to study sensory processing in vertebrate nervous systems has resulted in many neuroethological studies investigating the roles played by a single sensory modality in a given behavior. However, animals behaving in a complex, three-dimensional environment receive a large amount of information from external and internal receptor arrays. Clearly, the integration of sensory afference arising from different modalities into a coherent 'gestalt' of the world is essential to the behaviors of most animals. Over the past several years researchers in my laboratory have examined the roles played by the visual and lateral line sensory systems in organizing the feeding behavior of two species of predatory teleost fishes, the largemouth bass, Micropterus salmoides and the muskellunge, Esox masquinongy. The free-field feeding behaviors of these fishes was studied quantitatively in intact animals and compared to animals in which the lateral line and visual systems had been selectively suppressed. The data show that both bass and muskie employ similar approach and strike behaviors. Vision is crucial to the initial detection of, and orientation to, prey. Lateral line and vision together determine the optimum distance and angular deviation for the initiation of a rapid strike toward the prey. Blinded animals are able to strike accurately at prey at very close ranges and small angular deviations, indicating that this modality presents sufficient information to direct the behavior during the final phases of the strike. The results demonstrate that there is a hierarchy of senses involved in feeding behavior, with different modalities playing critical roles in succeeding phases.