Physiological Relationships Between Insects and Their Host Plants

Summary It is shown that under late summer conditions of light the rate of reproduction of the aphis, Brevicoryne brassicae, is positively correlated with the nitrogen content of the host plant and, in particular, with the protein content. The formation of winged forms is negatively correlated with the same factors. The chemical composition of the plant affects the rate of growth, length of larval period and final pupal weights of Pieris brasscae. It also influences the amount of food eaten.