TY - JOUR
T1 - Resource-driven changes to host population stability alter the evolution of virulence and transmission
AU - Hite, Jessica L.
AU - Cressler, Clayton E.
N1 - Funding Information:
Funding. This research was supported by funding from the University of Nebraska-Lincoln. Acknowledgements. We thank Dan Becker, Richard Hall, Kristian Forbes, Raina Plowright and Sonia Altizer for inviting us to contribute to this special issue.
PY - 2018/5/5
Y1 - 2018/5/5
N2 - What drives the evolution of parasite life-history traits? Recent studies suggest that linking 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 processes (host density, stability, transmission) to virulence evolution, using a ‘non-nested’ model. Then, we consider a ‘nested’ model where population-level processes (trans-mission and virulence) depend on resource-driven changes to individual-level (within-host) processes (energetics, immune function, parasite pro-duction). 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’.
AB - What drives the evolution of parasite life-history traits? Recent studies suggest that linking 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 processes (host density, stability, transmission) to virulence evolution, using a ‘non-nested’ model. Then, we consider a ‘nested’ model where population-level processes (trans-mission and virulence) depend on resource-driven changes to individual-level (within-host) processes (energetics, immune function, parasite pro-duction). 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’.
KW - Adaptive dynamics
KW - Consumer-resource
KW - Nested models
KW - Parasite evolution
KW - Transmission
KW - Virulence
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U2 - 10.1098/rstb.2017.0087
DO - 10.1098/rstb.2017.0087
M3 - Article
C2 - 29531142
AN - SCOPUS:85044078460
VL - 373
JO - Philosophical Transactions of the Royal Society B: Biological Sciences
JF - Philosophical Transactions of the Royal Society B: Biological Sciences
SN - 0800-4622
IS - 1745
ER -