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About the Authors:
Julia Olszewski
Contributed equally to this work with: Julia Olszewski, Melanie Haehnel
Affiliation: Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island, United States of America
Melanie Haehnel
Contributed equally to this work with: Julia Olszewski, Melanie Haehnel
Affiliation: Department of Biology, The Whitney Laboratory for Marine Bioscience, University of Florida, Saint Augustine, Florida, United States of America
Masashige Taguchi
Affiliation: Department of Biology, The Whitney Laboratory for Marine Bioscience, University of Florida, Saint Augustine, Florida, United States of America
James C. Liao
* E-mail: [email protected]
Affiliation: Department of Biology, The Whitney Laboratory for Marine Bioscience, University of Florida, Saint Augustine, Florida, United States of America
Introduction
The mechanosensory lateral line system allows fishes to detect water flow relative to the body. The basis of this sensory system is an array of receptor units called neuromasts, which contain clusters of hair cells along with support cells. Upon deflection, hair cells increase transmitter release and excite afferent neurons [1]. While adult fishes may possess tens of thousands of neuromasts, larval zebrafish (Danio rerio) contain only about 24 on the surface of the body [2] at 5 days post fertilization (dpf). Even at this early developmental stage, zebrafish larvae exhibit several distinct motor behaviors which are mediated by the lateral line, such as turns, struggling and escape behaviors [3]–[8]. Due to its accessibility and tractability, the larval lateral line is uniquely suited for experimental studies involving selective neuromast ablations. This provides an attractive opportunity to manipulate neuromast number and arrangement in order to investigate the functional consequence of the spatial organization of flow sensors in an intact, freely-swimming animal.
Several species of predatory fishes and invertebrates prey on zebrafish using suction feeding, making the ability to detect and avoid high velocity flows critical for their survival [9]. Zebrafish are found in moderate flowing streams throughout Southeast Asia but congregate in slow flowing or stagnant side pools [9], [10]. The innate tendency to orient and swim against a current is called rheotaxis [11]. This behavior is mediated by the neuromasts of the lateral line system, and can proceed even in the absence of visual cues [11]. Although rheotaxis in adult fishes has received much attention [12]–[15], very little is known about rheotaxis and...