Abstracts (first author)
The role of host sex in parasite evolution
The most extreme inter-individual differences within species are often those between sexes. In populations of sexual species, these intersexual differences often include strong dimorphism in parasite prevalence, disease symptoms and virulence. These effects of host sex have traditionally been attributed to sex-specific differences in host properties such as behavior, immune responses, hormone balances and resource allocation. However, these profound differences between males and females may act as alternative “environments” for infectious parasites and may result in parasite lineages that are differently adapted to each host sex. Here, I will present different conceptual scenarios in which host sex can affect parasite evolution, illustrated with my empirical studies of bacteria evolving naturally in Daphnia or experimentally in Drosophila. A better understanding of specific adaptation of parasites to the host sexes will help us to understand sexual dimorphism in disease responses. Moreover, it will allow us to investigate how parasitism could favor the evolution of sexual dimorphism by reducing the probability that parasites could evolve optimal fitness across both host sexes.