Collaborative Research: The Evolution of Tolerance to Herbivory among Populations of Scarlet Gilia, Ipomopsis aggregata

Michigan State University, East Lansing MI

Investigators

Abstract

0108354 Conner Plant responses to herbivory can be divided into two components, plant defenses and tolerance. Tolerance refers to the ability of plants to regrow and reproduce following herbivore damage; i.e., the ability to compensate. Yet little is known about how tolerance evolves, with most studies to date focusing on plant defense. Over the past fifteen years studies have been conducted on a specialized case of tolerance in a biennial/perennial herb, scarlet gilia, where plants have been observed to achieve greater reproductive success by overcompensating for tissues lost to herbivory. However, scarlet gilia's compensatory response is not universal; exhibiting tremendous variation both within and between populations. To assess whether there is a genetic basis to population differences in compensation, as well as whether selection on plant traits related to compensation differ between populations and locations, reciprocal transplant experiments and selection analyses will be conducted. These studies will be conducted within each of four populations that have been subjected to very different historical levels of herbivory; two of these overcompensate and the other two do not. Studies on the relative importance of genetic versus environmental factors and selection in different environments should contribute to our understanding of the evolutionary response of plants to herbivory, and add general understanding to the factors that do and do not lead to enhanced reproductive success following herbivory. If the mechanisms of overcompensation are genetically based, such responses to herbivory should be of great interest to agriculturists who, through recent advents in molecular genetic technique, might incorporate these traits into crop plants.