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Phenotypic convergence along a gradient of predation risk
S R Dennis1, Mauricio J Carter, W T Hentley
1Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK. stuart.dennis@sheffield.ac.uk
Proceedings. Biological Sciences
|November 19, 2010
Summary
Phenotypic plasticity, the ability of an organism to change its phenotype in response to environmental changes, can drive population convergence. This study shows Daphnia pulex populations converge in phenotype under predation pressure.
Area of Science:
- Ecology
- Evolutionary Biology
- Zoology
Background:
- Phenotypic variation among populations is a key ecological question.
- Phenotypic plasticity's role in this variation is debated, with previous studies limited in scope.
Purpose of the Study:
- To investigate if phenotypic plasticity drives phenotypic convergence in Daphnia pulex populations.
- To quantify predator-induced plasticity across multiple traits and environments.
Main Methods:
- Examined two genetically distinct Daphnia pulex populations with different predation histories.
- Quantified predator-induced plasticity across 11 traits along a predation risk gradient.
- Utilized phenotypic trajectory analysis (PTA) to characterize multivariate reaction norms.
Main Results:
- Univariate analyses showed increased age, size at maturity, and defensive spikes in response to predation.
- PTA revealed whole-organism phenotypic strategies against predation pressure.
- Populations converged in phenotypic space as predation risk increased, despite occupying different spaces initially.
Conclusions:
- Phenotypic plasticity can lead to convergence in phenotypes between genetically distinct populations.
- PTA provides a powerful tool for understanding whole-organism responses to environmental pressures like predation.
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