RUI: The Herbivory Uncertainty Principle - How Experimenter Visitation and Measurement Affect Herbivory and Plant Growth

Muhlenberg College, Allentown PA

Investigators

Abstract

The Herbivory Uncertainty Principle - How Experimenter Visitation and Measurement Affect Herbivory and Plant Growth PI: Richard A. Niesenbaum, Muhlenberg College CO-PI: James F Cahill, University of Alberta CO-PI: Christine M. Ingersoll, Muhlenberg College In 1927,Werner Heisenberg proposed that there are fundamental limitations to the study of subatomic particles, as the act of measuring them can affect their behavior. Our prior work confirms that such uncertainty also occurs in ecological studies, where visiting plants to measure rates of herbivory actually changes those rates and significantly impacts the plant-insect interactions being studied. The implications of such "visitation effects" are enormous, and the proposed work will permit us to more substantially test whether visitation and measurement of plants alters rates of herbivory and plant growth, and will increase our understanding of the mechanisms responsible for these effects. We will examine how the presence of neighboring plants and local light environment influence the occurrence of "visitation effects", and how visitation and touch influence plant chemistry and insect foraging in the plant, Apocynum cannabinum. Results from the proposed research will challenge the long-standing assumption that field researchers are "benign observers", as the essential act of visiting plants during an experiment could alter the performance of those plants. A significant visitation effect may motivate us to re-think the way that we measure and test hypotheses about herbivory, plant growth and productivity, and other plant-animal interactions. This work is essential to understanding possible strategies to mitigate any potential observer effect in future studies, and will provide information about the basic ecology of plant-animal interactions in natural plant communities. An additional major goal is to advance undergraduate education by giving students primary roles in a significant ecological research project.