Data and code from: Spatially structured host genetic diversity leads to the evolution of local specialization

Host heterogeneity and spatial population structure each influence
parasite evolution and may interact when space structures contacts between
host types. Here, we experimentally evolve granulosis virus in microcosms
of its natural Plodia interpunctella (Indian meal moth) host that differ
in both spatial structure and host genetic diversity. We control spatial
structure by manipulating the viscosity of the food that the larvae live
within and host genetic diversity by adding larvae from either one or two
non-evolving inbred lines to opposite microcosm ends. We preserve spatial
structure across passages and assay virus from different positions within
the microcosm on both host genotypes. We find that the lower contact rates
between host genotypes resulting from spatial structure can lead to the
evolution of locally specialized virus, even when the host population is
genetically diverse overall. We also find that spatial structure changes
how viruses specialize: viruses evolved in well-mixed environments had
lower exploitation rates (proportion infected x virions) on the host they
evolved with, while those in spatially structured environments exhibited
higher exploitation of familiar hosts. These results demonstrate that
spatial structure and host heterogeneity interact to shape pathogen
specialization and that the evolutionary consequences of host diversity
depend on population structure.