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Epidemiological, evolutionary, and coevolutionary implications of context-dependent parasitism
Pedro F Vale1, Alastair J Wilson, Alex Best
1Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Ashworth Labs, West Mains Road, Edinburgh, Scotland, United Kingdom. pedro.vale@cefe.cnrs.fr
The American Naturalist
|April 5, 2011
Summary
Environmental factors like temperature and food availability can significantly alter parasite-host interactions. Changes can shift infections from severe to tolerable, impacting host populations and pathogen evolution.
Area of Science:
- Ecology
- Evolutionary Biology
- Parasitology
Background:
- Parasite population growth often correlates with increased host damage.
- However, some infections remain tolerable despite faster parasite growth, suggesting modulating factors.
- Understanding these factors is crucial for predicting disease dynamics.
Purpose of the Study:
- To investigate how environmental variation influences the relationship between parasite growth and host health.
- To determine if simple environmental changes can shift host-parasite interactions from severe to tolerable.
- To explore the evolutionary and epidemiological consequences of altered infection severity.
Main Methods:
- Experimental infections using Daphnia magna and the bacterial parasite Pasteuria ramosa.
- Manipulation of environmental variables, specifically temperature and food availability.
- Modeling of pathogen evolution and disease spread under varying infection severities.
Main Results:
- Host-parasite interactions shifted from severe to tolerable by altering temperature and food availability.
- Environmental shifts promoting tolerance led to increased prevalence of parasitized hosts.
- The opportunity for selection varied significantly across different environmental treatments.
Conclusions:
- Environmental variation plays a critical role in modulating host-parasite interactions and infection tolerance.
- Shifts in environmental conditions can lead to increased parasite prevalence and influence pathogen evolution.
- Spatial variation in tolerance and the opportunity for selection may explain coevolutionary hotspots and coldspots.
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