Data for: Feedback between coevolution and epidemiology can help or hinder the maintenance of genetic variation in host-parasite models

Antagonistic coevolution has long been suggested to help maintain host
genetic variation. While, ecological and epidemiological
feedbacks are known to have important consequences on coevolutionary
allele frequency dynamics, their effects on the maintenance of genetic
variation remains poorly understood.Here, we extend our previous work on
the maintenance of genetic variation in a classic matching-alleles
coevolutionary model by exploring the effects of ecological and
epidemiological feedbacks, where both allele frequencies and population
sizes are allowed to vary over time.  We find that coevolution
rarely maintains more host genetic variation than expected under neutral
genetic drift alone.  When and if coevolution maintains or
depletes genetic variation relative to neutral drift is
 determined, predominantly, by two factors: the deterministic
stability of the Red Queen allele frequency cycles and the chance of
allele fixation in the pathogen, as this results in directional selection
and depletion of genetic variation in the host. Compared to purely
coevolutionary models with constant host and pathogen population sizes,
ecological and epidemiological feedbacks stabilize Red Queen cycles
deterministically, but population fluctuations in the pathogen increase
the rate of allele fixation in the pathogen, especially in epidemiological
models.  Our results illustrate the importance of considering the
ecological and epidemiological context in which coevolution occurs when
examining the impact of Red Queen cycles on genetic variation.