Food Selection of the Ciliated Protozoa, Condylostoma vorticella (Ehrenberg) in Lake Kasumigaura

Abstract

The food selection of a herbivorous ciliated protozoa, Condylostoma vorticella (Ehrenberg) was examined in November 1980 in Takahamairi Bay of Lake Kasumigaura, using Ivlev's (1955) electivity index. This ciliated protozoa selectively fed on Synechococcus, Kirchneriella, Dictyosphaerium, Cosci-nodiscus, Cryptomonas, Chlamydomonas, and Gomphosphaeria, but rejected Closterium, Phormidium, Synedra, Tetrastrum, Dactylococcopsis, Scenedesmus, Aphanizomenon, Melosira, and Micractinium. The size and shape of algae were significant in the food selection, but the taxonomical groups were insignificant. The ciliate fed efficiently on food particles between 15 mm and 40 mm in size, but not filamentous and spindlelike algae or algae with long spines. © 1983, The Japanese Society of Limnology. All rights reserved.