EXPERIMENTAL MANIPULATION OF PUTATIVE SELECTIVE AGENTS PROVIDES EVIDENCE FOR THE ROLE OF NATURAL ENEMIES IN THE EVOLUTION OF PLANT DEFENSE.
Although biologists have long assumed that plant resistance characters evolved under selection exerted by such natural enemies as herbivores and pathogens, experimental evidence for this assumption is sparse. We present evidence that natural enemies exert selection on particular plant resistance characters. Specifically, we demonstrate that elimination of natural enemies from an experimental field population of Arabidopsis thaliana alters the pattern of selection on genetic variation in two characters that have been shown to reduce herbivore damage in the field: total glucosinolate concentration and trichome density. The change in pattern of selection reveals that natural enemies imposed selection favoring increased glucosinolate concentration and increased trichome density, and thus, supports one of the major assumptions of the coevolution hypothesis. We also demonstrate that a pattern of stabilizing selection on glucosinolate concentration results from a balance between the costs and benefits associated with increasing levels of this resistance character. This result provides direct confirmation of the appropriateness of cost-benefit models for characterizing the evolution of plant defenses.
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Related Subject Headings
- Evolutionary Biology
- 3104 Evolutionary biology
- 3103 Ecology
- 0603 Evolutionary Biology
- 0602 Ecology
Citation
Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Evolutionary Biology
- 3104 Evolutionary biology
- 3103 Ecology
- 0603 Evolutionary Biology
- 0602 Ecology