Many species of organisms can adopt different outward characteristics in different environmental situations. This phenomenon is called phenotypic plasticity. Such plasticity has been found in many aquatic organisms where the different environments that elicit the alternate characteristics involve the presence or absence of particular potential predators. While plasticity in such cases is assumed to provide some advantage to the organism, in many cases this cause-effect relationship is difficult to demonstrate. The characteristics adopted in the presence of the predators may result in lower vulnerability to predation, or may simply reflect developmental changes that afford the individual no particular advantage. %%% This proposed research involves phenotypic plasticity in the freshwater crustacean Daphnia in response to the presence of predaceous larvae of the insect Chaoborus. The research will result in useful information about the evolutionary importance of phenotypic plasticity. In particular, they will help clarify the extent to which plasticity is advantageous, rather than simply reflecting random changes with respect to the environment. Such information will be important in evaluating how organisms can adopt to a changing environment, such as might result from global warming.***//
