Differential Adaptation in Spacially Heterogeneous Environments and Host-Parasite Coevolution

Abstract

The terms adaptive deme formation and local adaptation have been used in the plant-herbivore and host-parasite literature, respectively, to designate one of the following two situations. The first one is when the mean fitness of a population (or deme) is on average larger in the environment this population originated from than in other environments. The second situation is when the mean fitness of a population on its natal environment is on average larger than the mean fitness of populations issued from other environments. We will use the term local adaptation to designate the situation when both conditions are satisfied, though this is not always the case. This definition emphasizes the potential differential response of populations with respect to their natal versus nonnatal environments, a phenomenon that should not be restricted to biotic interactions only.