Hydrodynamic contributions to multimodal guidance of prey capture behavior in fish

Water movements, of both abiotic and biotic origin, provide a wealth of information of direct relevance to the guidance of prey capture behavior. To gather hydrodynamic information, fish have sensors of two basic types: those scattered over the surface of the body known as superficial neuromasts and similar sensors embedded in subdermal lateral line canals. Recently, the anatomical dichotomy between superficial and canal neuromasts has been matched by demonstrations of a corresponding functional dichotomy. Prey detection and localization are evidently mediated by canal neuromasts, whereas superficial neuromasts are more sensitive to water flows over the surface of the fish and participate in the orientation to water currents, a behavior known as rheotaxis. However, rheotaxis in combination with chemosensory inputs can also guide fish to their prey. Thus there is evidence that both lateral line sub-modalities either alone or in concert with other senses play a role in prey capture. Are there circumstances where prey capture requires integration of information from both lateral line sub- modalities? Recent evidence shows that fish are capable of tracking other fish on the basis of the hydrodynamic trails left behind by their swimming motion. Pharmacological and physical ablation of lateral line end organs shows that indeed integration of information from both sub-modalities is required for the complex hydrodynamic task of natural prey capture in the dark. Furthermore, these experiments provide an excellent demonstration of the integration of hydrodynamic, chemosensory, tactile and visual information for the multimodal guidance of prey capture behavior.