Prey size and risk of predation are strongly related to the medium-sized Daphnia -- a small, planktonic crustacean -- targeted by aquatic insects and fish. This phenotypic plasticity has been shown to be expressed by a variety of factors, including predator type, predator mode, and density. Overall, the small and medium-sized Daphnia expressed the highest degree of predator-induced plasticity, which the team found was more evident in small Daphnia than would be expected from size-selective predation.