Interaction Between Plant Competition And Resistance In Maintaining A Plant Defense Dimorphism

University Of California-Riverside, Riverside CA

Investigators

Abstract

0089519. Daniel Hare Individual plants within populations vary widely in their ability to resist attack by herbivores. Understanding this variation, and how different resistance traits evolve and coexist, is a major focus of contemporary ecology. Because resistance traits are costly to maintain, the strength of selection for resistant and susceptible phenotypes can vary with herbivore intensity, and/or other forces such as environmental conditions or competitive interactions. Furthermore, some resistance traits may be genetically linked with plant life-history traits that increase fitness, resulting in the conservation of resistance traits even when herbivores are absent. This empirical study will use field experiments to discern the indirect and direct costs and benefits of trichome polymorphism in Datura wrightii. The study has three primary objectives. Objective one and two will use greenhouse experiments to 1) evaluate the impact of herbivory on plants with and without the resistant traits, and 2) assess competitive interactions between plant phenotypes in the presence and absence of herbivores. The third objective will use field observations to determine the extent of herbivory, the identity of herbivores, and their fitness consequences in natural Datura populations. This work uses the Datura model, but the underlying principles are applicable for diverse insect-plant interactions and have relevance for both basic and applied science.