Data from: Linking sex differences to the evolution of infectious disease life-histories

Sex differences in the prevalence, course and severity of infection are widespread, yet the evolutionary consequences of these differences remain unclear. Understanding how male–female differences affect the trajectory of infectious disease requires connecting the contrasting dynamics that pathogens might experience within each sex, to the number of susceptible and infected individuals that are circulating in a population. In this study, we build on theory using genetic covariance functions to link the growth of a pathogen within a host to the evolution and spread of disease between individuals. Using the Daphnia–Pasteuria system as a test case, we show that based on within-host dynamics alone, females seem to be more evolutionary liable for the pathogen, with higher spore loads and greater divergence among pathogen genotypes as infection progresses. Between-host transmission, however, appears to offset the lower performance of a pathogen within a male host, making even subtle differences between the sexes evolutionarily relevant, as long as the selection generated by the between-host dynamics is sufficiently strong. Our model suggests that relatively simple differences in within-host processes occurring in males and females can lead to complex patterns of genetic constraint on pathogen evolution, particularly during an expanding epidemic. This article is part of the theme issue 'Linking local adaptation with the evolution of sex differences'.Within-host-spore-countsRaw data of raw spore loads for male and female Daphnia sampled every two days after infection. Included are the genotype of the pathogen (Column Path: C24, C19, C20, C14, C18 or C01), the sex of the infected host (Column Sex: M, F), the sampling age (Column Age: in days post infection), and the spore loads (Column Spores_mil: mature transmission spores in millions per animal). Spore loads at each time point were estimated by destructively sampled up to 20 infected individuals per sex and genotype combination