Plant Genotypic Diversity And Its Influence On Arthropod Communities
Genotypic diversity varies markedly among populations of organisms, however the ecological consequences of intraspecific diversity are poorly understood. Here I directly compare the effects of plant species and genotypic diversity on arthropod communities and ecosystem functioning. Through behavioral observations, field experiments, and laboratory assays, I show contrasting mechanisms by which arthropod species richness and evenness are altered by each type of plant diversity. I then show how genotypic diversity of the common evening primrose (Oenothera biennis) reduces herbivory by changing herbivore behavior and physiology, ultimately decreasing consumption efficiency. Finally, I show how O. biennis genotypic diversity attenuates induced plant resistance to the Japanese beetle (Popillia japonica), indirectly increasing plant susceptibility to three native seed predators. As a result, this highly invasive beetle actually increases the fitness of O. biennis by consuming it. Overall, I show that plant genotypic diversity contributes substantially to the structure and functioning of arthropod communities through both direct and indirect mechanisms.
Thaler, Jennifer S.
Ph.D. of Entomology
Doctor of Philosophy
dissertation or thesis