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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 1537

Kevin L. Kirk and John J. Gilbert; Escape behavior of Polyarthra in response to artificial flow stimuli. Bull.mar.Sci. 43(3):551-560, 1988

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We investigated the escape response of the rotifer Polyarthra remata using three-dimensional videographic analysis. In nature, these high-velocity escape responses may be elicited by the feeding currents of interference competitors and predators. Because the natural flow field which elicits these escape responses is a simple, steady current, and because the behavioral response is an all-or-none phenomenon, this system is ideal for experimental studies on the mechanosensory basis of zooplankton behavior. We simulated the inhalant currents of feeding cladocerans by using siphons as artificial flow simulus sources. The siphon flow fields were similar to the currents produced by feeding cladocerans with respect to the dimensions of the flow field and the attenuation of flow velocity and acceleration with distance from the stimulus source. The threshold flow velocities and accelerations associated with the release of the escape response of P. remata were 0.98-2.98 mm/sec and 2.21-36.20 mm/sec, respectively, and increased with the overall velocity of the siphon flow field. These results support the hypothesis that the escape response can be elicited by simple flow fields alone. They do not support the hypothesis that velocity and acceleration are the flow properties which best describe the amplitude of the flow stimulus which releases the escape response.