Macroevolutionary Trends of Defenses and Counterdefenses in an Ancient Plant-Insect Interaction

University Of Arizona, Tucson AZ

Investigators

Abstract

9982040 Becerra Determining the macroevolutionary importance of plant defenses on the association between plants and the insects that eat them is critical to understanding the evolution of insect-plant interactions. Yet, until recently, this has been a difficult area of investigation because it requires rigorously derived evolutionary trees of interacting groups of insects and plant for which systematics, biogeography, ecology, and plant defensive traits are well known. This research is directed at providing a quantitative assessment of the role of plant structure and chemical defenses, host cladogenesis, and host biogeographical distributions in directing the evolution of host shifts. In this study, the evolutionary trees of the ancient and speciose Blepharida (Chrysomelidae) - Bursera (Burseraceae) system will be reconstructed. Also, profiles of structural and chemical defenses, as well as maps of geographic distributions for the plant species will be obtained to determine their relative importance in directing the evolution of these insects on these plants. Besides studying the macroevolutionary impact of plant defenses, this research will investigate the historical correlation of plant defenses with insect counter-defenses. This plant-herbivore system has spectacular defensive and counter-defensive traits that are well understood ecologically. Overall, this study will advance knowledge by providing a precise evaluation of the importance of plant defensive chemicals and defensive morphology in the macroevolution of host exploitation. It will be the first study to rigorously utilize molecular phylogenies for both insect and plant groups in the study of plant-insect coevolution.