Ref ID : 686
John J. Gilbert; The Polyarthra escape from response: Defense against interference from Daphnia. Hydrobiologia 147:235-238, 1987
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Direct observations show that almost all (97%) Polyarthra remata caught in the inhalant current of Daphnia pulex avoid inhalation by initiating escape responses. Microvideographic analysis shows that these responses are initiated, on average, 0.24 mm (about 2.5 body lengths) from the inhalant opening of the branchial chamber, when the Polyarthra are moving at a velocity of about 1.4 mm/sec (about 6 times their normal swimming speed -0.24 mm/sec). The stimulus for the escape response could be rapid acceleration or, more likely, shear. The average distance traveled during an escape response is at least 1.25 mm (about 12 body lengths). The Polyarthra escape response can provide a very effective defense against interference from Daphnia and may greatly increase the ability of Polyarthra spp. to coexist with Daphnia.