Life-history evolution of class-structured populations in fluctuating environments

What is the influence of periodic environmental fluctuations on life-history evolution? We present a general theoretical framework to understand and predict the long-term evolution of life-history traits under a broad range of ecological scenarios. Indeed, this analysis yields time-varying selection gradients that help dissect the influence of the fluctuations of the environment on the competitive ability of a specific life-history mutation. We use this framework to analyse the evolution of key life-history traits of pathogens, such as transmission and virulence. These examples reveal how periodic fluctuations of the environment can affect the evolution of pathogens, and illustrate the usefulness and broad applicability of this new approach.