Data from: Fine-scale spatial covariation between infection prevalence and susceptibility in a natural population

The prevalence of infection varies dramatically on a fine spatial scale.
Many evolutionary hypotheses are founded on the assumption that this
variation is due to host genetics, such that sites with a high frequency
of alleles conferring susceptibility are associated with higher infection
prevalence. This assumption is largely untested and may be compromised at
finer spatial scales where gene flow between sites is high. We put this
assumption to the test in a natural snail-trematode interaction in which
host susceptibility is known to have a strong genetic basis. A decade of
field sampling revealed substantial spatial variation in infection
prevalence between 13 sites around a small lake. Laboratory assays
replicated over 3 years demonstrate striking variation in host
susceptibility among sites in spite of high levels of gene flow between
sites. We find that mean susceptibility can explain more than one-third of
the observed variation in mean infection prevalence among sites. We
estimate that variation in susceptibility and exposure together can
explain the majority of variation in prevalence. Overall, our findings in
this natural host-parasite system argue that spatial variation in
infection prevalence covaries strongly with variation in the distribution
of genetically based susceptibility, even at a fine spatial scale.