Particle selection over a broad size range by crustacean zooplankton

1. Preferences for particles over a broad size range were assessed in four crustacean zooplankton species under field conditions. The particles employed were six spherical algae with diameters of 2, 6, 13, 19, 38 and 61 μm. 2. Diaphanosoma brachyurum and Daphnia cucullata preferred the two smallest particles, Chydorus sphaericus the three smallest and Eudiaptomus gracilis the 19 μm particle. 3. These size preferences agree well with earlier determinations based on seston particles in the same lake, indicating consistent size preferences by these species over a broad size range.