Document: ANU-3-2-6

Evolutionary ecology of species interactions: The importance of phenotypic plasticity.

AGRAWAL, A.A.*

University of Toronto, Toronto, ON M5S 3B2 CANADA ¹

Abstract:
I will consider three areas of research that focus on species interactions and phenotypic plasticity. Verbal and mathematical models have long predicted the importance of phenotypic plasticity in the evolutionary ecology of species interactions. For example, prominent adaptations of plants (e.g., defensive chemicals) and herbivores (e.g., detoxification enzymes) have plastic expression. 1) These adaptations may be the result of coevolution between species that have variable interactions. The raw material for coevolution of plasticity requires genetic variation for plasticity of traits involved in the interaction. How does selection imposed by each player act on these plastic traits in the other? 2) A signature of coevolution that has resulted in phenotypic plasticity is the escalation of phenotypes between the interacting species in ecological time. Over the course of an extended bout of interactions, does each species adjust its phenotype in response to the other, and does reciprocal phenotypic change result in an ecological arms race? What are the implications for agricultural pest management? 3) Phenotypic plasticity may primarily evolve to maximize fitness in variable environments, but plasticity may have evolutionary consequences as well. Are organisms with phenotypic plasticity better able to colonize new environments, and is this associated with isolation and genetic differentiation? If so, phenotypic plasticity may play an important role in ecological interactions resulting from coevolution and in evolutionary dynamics resulting from ecological variation.

Keywords: plant-insect interactions, phenotypic plasticity, coevolution

This abstract is being presented at: 9:15 AM in session:
Symposium # 7: Thirty Questions for Ecology in the 21st Century.