Parasitic plants offer numerous advantages for studying the eco-evolutionary dynamics of parasitism.  S. hermonthica hosts are characterized by mating systems from highly outcrossing (pearl millet and maize) to predominately selfing (sorghum) and a diversity of abiotic requirements. Unlike many microbial pathogens and endoparasites, parasite generation times are similar to their hosts (~1 year) leading to more balanced coevolutionary dynamics. The potential for reciprocal coevolution (rather than asymmetrical adaptation of parasites to hosts often assumed in agricultural settings) is supported by a recent study of sorghum and S. hermonthica. Bellis et al. (2020) found evidence that S. hermonthica prevalence imposed spatially-varying selection on sorghum landraces, promoting among-population diversity in sorghum alleles for S. hermonthica resistance. Parasitic plants are large and conspicuous, so excellent occurrence data are available from natural history collections without a need for dissections or molecular diagnostics. Host specialized as well as generalist populations are known (Parker and Reid 1979). However, the eco-evolutionary determinants of specialization are poorly characterized, despite detailed knowledge at the molecular level on parasitic plant response to different hosts (Honaas et al. 2013, Johnson et al. 2019, Lopez et al. 2019).