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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 1658

Jeffrey D. Jack and John J. Gilbert; Susceptibilities of different-sized ciliates to direct suppression by small and large cladocerans. Freshwater Biology 29:19-29, 1993

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1. Laboratory experiments compared the susceptibilities of six ciliates and the rotifer Keratella cochlearis to predation and interference from Daphnia pulex and Bosmina longirostris. 2. Susceptibilities of the ciliates to D. pulex were similar to or less than that of the rotifer, and decreased with increasing ciliate size. Most ciliates were just as susceptible to B. longirostris as to the much larger D. pulex. The jumping response of the oligotrich Strobilidium gyrans appeared to be an effective defense against B. longirostris. 3. Clearance rates of B. longirostris and D. pulex on different ciliate species at a density of 1.3 ciliates ml-1 ranged from 1-30 to 5-24 ml ind.-1 day-1, respectively. In natural plankton communities, cladocerans could impose high mortality rates on ciliates and shift the size structure of ciliate assemblage towards larger and less susceptible species.