Fig. 5: The RI groups maintain isolation despite coexistence.

a, Genotypes of het-v and het-r in the Wageningen population through time. The rV1 genotype is very rare, confirming that the RI groups (RV1 and rV) are not mixing freely. RV is lethal. b, There is no significant difference (NS) in abundance between RI groups based on the source herbivore (Pearson’s Χ²_{1, 82} = 0.46365, P = 0.4959; genotyped samples from 1991 to 2016 with substrate data, n = 82). Sheep dung was not tested due to low sample sizes. c, The strains collected in 2017 from horse dung (plus one sample from sheep) show that the RI groups can be found in the same dung piece (n = 63). Insert, fruiting body of P. anserina in the wild (photo by S.L.A.V.).