10.6084/m9.figshare.5802651.v1 Jessica L. Hite Jessica L. Hite Clayton E. Cressler Clayton E. Cressler Supplemental Figures from Resource-driven changes to host population stability alter the evolution of virulence and transmission The Royal Society 2018 parasite evolution virulence transmission consumer-resource nested models adaptive dynamics 2018-01-19 12:29:44 Journal contribution https://rs.figshare.com/articles/journal_contribution/Supplemental_Figures_from_Resource-driven_changes_to_host_population_stability_alter_the_evolution_of_virulence_and_transmission/5802651 What drives the evolution of parasite life-history traits? Recent studies suggest that feedbacks between within- and between-host processes can provide key insight into both disease dynamics and parasite evolution. Still, it remains difficult to understand how to pinpoint the critical factors connecting these cross-scale feedbacks, particularly under non-equilibrium conditions; many natural host populations inherently fluctuate and parasites themselves can strongly alter the stability of host populations. Here, we develop a general model framework that mechanistically links resources to parasite evolution across a gradient of stable and unstable conditions. First, we dynamically link resources and between-host (host density, stability, transmission) processes to virulence evolution. Then, we consider a ‘nested’ model where population-level processes (transmission and virulence) depend on resource-driven changes to individual-level (within-host) processes (energetics, immune function, parasite production). Contrary to ‘non-nested’ model predictions, the nested model reveals complex effects of host population dynamics on parasite evolution, including regions of evolutionary bistability; evolution can push parasites towards strongly or weakly stabilizing strategies. This bistability results from dynamic feedbacks between resource-driven changes to host density, host immune function and parasite production. Together, these results highlight how cross-scale feedbacks can provide key insights into the structuring role of parasites and parasite evolution.This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife’.