Theory of Fitness in a Heterogeneous Environment. II. Developmental Flexibility and Niche Selection

Abstract

The mathematical argument of the previous paper is extended to show that the optimal pattern of development is continuous variation of phenotype with environment if the difference between alternative niches is small compared to the individuals'' tolerance, a switch mechanism if the niche difference is large compared to tolerance and both niches occur simultaneously, and a stochastic switch when the difference between niches is large and the environment is uniform in space but variable in time. It is shown that there is an optimum level of niche selectivity which depends on the probability of finding the preferred niche and that both developmental flexibility and niche selection reduce the likelihood that polymorphism will be advantageous. Several experimental approaches toward testing the theory are discussed.