Crustaceans and rotifers in the predatory feeding of Utricularia

The contents of bladders in the predatory plant Utricularia from three waterbodies were studied. The composition and number of prey depended on the development of zooplankton and phytophilous fauna in the environment. The probability of getting the prey into the bladder was determined by the specificity of the prey's behavior and size. The most numerous prey were predatory Copepoda and nonpredatory Cladocera, which use the bladderwort as a substrate. The shares of other cladocerans in the bladders were inconsiderable when there were high densities of these species in the waterbody. No negative impact of the bladderwort on the rotifer abundance was revealed.