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Host-parasite coevolutionary arms races give way to fluctuating selection
Alex R Hall1, Pauline D Scanlan, Andrew D Morgan
1Department of Zoology, University of Oxford, Oxford OX1 3PS, UK. alex.hall@zoo.ox.ac.uk
Ecology Letters
|April 28, 2011
Summary
Host-parasite coevolutionary arms races slow down over time due to increasing costs of generalism. Fluctuating selection on genotypes becomes more important, impacting host-parasite dynamics and biological diversity.
Area of Science:
- Evolutionary biology
- Microbial ecology
- Genetics
Background:
- Host-parasite coevolution drives biodiversity and virulence.
- Short-term studies often show escalating 'arms race' dynamics.
- The long-term trajectory of these interactions is less understood.
Discussion:
- Arms race dynamics decelerate over time in Pseudomonas fluorescens and phage SBW25Φ2.
- Increasing costs of generalism for both host and parasite limit escalation.
- Fluctuating selection on individual genotypes becomes a dominant force.
Key Insights:
- Coevolutionary arms races are not always sustained escalations.
- Costs of generalism play a critical role in shaping long-term coevolutionary patterns.
- Shifting selection pressures influence population-level phenotypes.
Outlook:
- Arms race deceleration may be common in other coevolving systems.
- Understanding long-term dynamics is crucial for predicting evolutionary trajectories.
- This research informs broader ecological and evolutionary theory.
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