We will investigate to what extend food quality, both in terms of P-limitation as well as PUFA-limitation, has an influence on the deployment of defense responses of the waterflea Daphnia against parasites and predators. We expect that poor food quality, through its effect in reducing growth rate, limits the options of Daphnia to respond to predator or parasite exposure. Given that the animals can not react by investing more energy in growth, we predict that they will invest more in their defenses against enemies, so as to reduce mortality losses. We will also quantify the influence of food quality on maternal effects for defense responses, and will contribute to the analysis of genetic maps and QTLs of anti-predator traits in Daphnia.