In spatially structured host metapopulations (subdivided into isolated populations), this process of immune adaptation may lead to disparate phenotypic solutions, and population divergence (Brunner et al., 2013;Meihls et al., 2013;Weber, Kalbe, et al., 2017). Two populations may evolve to recognize different parasite antigens (e.g., a geographic mosaic of coevolution; Dodds & Thrall, 2009), use different facets of the immune system to achieve the same form of