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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 7623

Fritz Wenzel and Heinrich Liebsch; [Quantitative Untersuchungen zur Nahrungsaufnahme von Stentor coeruleus Ehrenberg] (Quantitative Studies on Feeding in Stentor coeruleus Ehrenberg). Zool.Anz.,Jena 195(5/6):319-337, 1975

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On Stentor coeruleus feeding and filtration rates and its relative preference as to particle size were evaluated under standardised conditions. An electronic particle counter (Coulter Counter) served for counting the particle concentrations in the suspensions. The experiments each of which lasted 5 hours showed that feeding and filtration rates depend on the duration of feeding and the concentration of particles (living Tetrahymena pyriformis) in suspension. At low T.-concentrations the filtration rate first increased, then continually decreased towards O; at medium and high T.-concentrations (2000-10,000 T./ml) the rate decreased from the beginning of feeding. The filtration rate depends on particle concentration as shown by the fact that with increasing T.-concentration - up to certain limit - the filtration rate remains constant whereas it decreases continuously after reaching the limiting concentration of ~~1300 T./ml. During the first two hours the average feeding rate above the limiting concentration was about 50 T./Stentor/hr. S. showed a marked relative preference to particle size (starch- and Sephadex-particles). Out of the offered size spectrum S. preferently chose particles of 7-22 µm diameter. All results were treated statistically. The relations between particle concentration, filtration rate and duration of filtration are explained by different consumption of membrane material for the formation of food vacuoles per incorporated T. and its dependence of T.-concentration. The filtering efficiency of S. is compared with that of other protozoan and metazoan filter-feeders. In this comparison S. turns out to be an organism with an good filtering efficiency.