9701330 Rausher The response of plants to herbivory has long been of interest to biologists. The majority of work in this area has focused on how plants defend themselves against herbivores - plant "resistance". However, plants may also tolerate herbivory (i.e. minimize the effect that herbivory has on productivity). Although plant tolerance to herbivore damage may dramatically alter how biologists think about plant-herbivore interactions, little is known about the ecology or genetics of tolerance. We will use field experiments and quantitative genetics to study the tolerance of the common morning glory, Ipomoea purpurea, to three types of herbivore damage. Specifically, we will i) measure genetic variation for tolerance, ii) characterize the genetic relationship between tolerance and other ecologically important traits, including resistance, and iii) measure the relationship between tolerance and plant productivity. The study of plant tolerance to herbivory may have important implications for agriculture. Herbivores are a major problem in modern agriculture leading to loss of productivity and requiring large inputs of expensive and environmentally harmful pesticides. Developing strains of crop plants that are more tolerant of herbivory may minimize the need to eliminate herbivore pests and therefore may contribute to more economically and environmentally sustainable agriculture. This study will provide important information on the genetics and ecology of tolerance which will be necessary for evaluating the role that plant tolerance may have in agricultural systems.