Projects per year
Abstract
Defensive symbionts in the host microbiome can confer protection from infection or reduce the harms of being infected by a parasite. Defensive symbionts are therefore promising agents of biocontrol that could be used to control or ameliorate the impact of infectious diseases. Previous theory has shown how symbionts can evolve along the parasitism–mutualism continuum to confer greater or lesser protection to their hosts and in turn how hosts may coevolve with their symbionts to potentially form a mutualistic relationship. However, the consequences of introducing a defensive symbiont for parasite evolution and how the symbiont may coevolve with the parasite have received relatively little theoretical attention. Here, we investigate the ecological and evolutionary implications of introducing a tolerance-conferring defensive symbiont into an established host–parasite system. We show that while the defensive symbiont may initially have a positive impact on the host population, parasite and symbiont evolution tend to have a net negative effect on the host population in the long term. This is because the introduction of the defensive symbiont always selects for an increase in parasite virulence and may cause diversification into high- and low-virulence strains. Even if the symbiont experiences selection for greater host protection, this simply increases selection for virulence in the parasite, resulting in a net negative effect on the host population. Our results therefore suggest that tolerance-conferring defensive symbionts may be poor biocontrol agents for population-level infectious disease control.
Original language | English |
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Article number | qrad015 |
Pages (from-to) | 262-272 |
Number of pages | 11 |
Journal | Evolution Letters |
Volume | 7 |
Issue number | 4 |
DOIs | |
Publication status | Published - 5 May 2023 |
Bibliographical note
B.A. is funded by Natural Environment Research Council grants NE/N014979/1 and NE/V003909/1. C.A.S. is funded by Natural Environment Research Council grant NE/V003909/1.Data Availability Statement
The Python code for the implementation of this model can be found at https://github.com/CameronSmith50/Defensive-Symbiosis.Fingerprint
Dive into the research topics of 'Tolerance-conferring defensive symbionts and the evolution of parasite virulence'. Together they form a unique fingerprint.Projects
- 2 Finished
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The eco-evolutionary dynamics of age-specific resistance to infectious disease
Ashby, B. (PI)
Natural Environment Research Council
1/06/20 → 31/01/24
Project: Research council
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Fellowship Ben Ashby - Host-parasite Coevolution in Complex Communities
Ashby, B. (PI)
Natural Environment Research Council
1/10/16 → 30/09/22
Project: Research council