The feeding behavior of Daphnia pulex from Lake Winnebago, Wisconsin1

Abstract

The feeding behavior of Daphnia pulex from Lake Winnebago was studied under conditions approximating those in the lake and in lake water enriched with algae in mixed culture. When one size particle offered a significantly larger biomass than the others in the water, the animals selected for the abundant particle; selection seemed to increase with increasing particle concentrations until consumption of the particle was maximized. When this mechanism was in operation, filtering rates on other particles were reduced. However, when the concentrations (by biomass) of all particles were approximately equal, selection was for small particles present in high numbers.