Grantee Research Project Results
The importance of natural enemies of herbivores as agents of selection for plant genotypes within species
EPA Grant Number: U915372Title: The importance of natural enemies of herbivores as agents of selection for plant genotypes within species
Investigators: Rudgers, Jennifer A.
Institution: University of California - Davis
EPA Project Officer: Packard, Benjamin H
Project Period: September 28, 1998 through January 1, 2000
Project Amount: $78,694
RFA: STAR Graduate Fellowships (1998) RFA Text | Recipients Lists
Research Category: Fellowship - Ecology , Ecological Indicators/Assessment/Restoration , Academic Fellowships
Objective:
In natural ecosystems both direct and indirect plant defenses can suppress herbivorous insect damage. Direct plant defenses include traits such as toxic secondary compounds that often decrease herbivore fitness and damage to plants. Indirect plant defenses are generally more subtle. These traits reduce herbivore fitness via an interaction with the enemies of herbivores. A classic example is the extrafloral nectary. In plants such as ant-acacias, extrafloral nectaries attract ants that patrol the leaves and remove herbivores. Indirect plant defenses have largely been neglected in agricultural systems. Crops are bred primarily for direct resistance to herbivores and indirect resistance traits may be lost in certain cultivars. Interactions between host plant traits and the natural enemies of herbivores could be important for pest control. In the process of breeding for direct plant resistance characters, we may be overlooking important plant traits that promote the effectiveness of natural enemies.
I intend to use a wild relative of cotton, Gossypium thurberi (Malvaceae), that is native to the Sonoran desert of North America as a model system for investigating the specific question: Are plant traits shaped by selection from the natural enemies of herbivores? In other words, are certain plant traits favored that allow natural enemies of herbivores to forage more efficiently, thereby reducing damage to the plant? I will focus on two of G. thurberi's major, native insect pests: the cotton leaf perforator, Bucculatrix thurberiella (Lepidoptera: Lyonetiidae), and the cotton boll weevil, Anthonomus grandis (Coleoptera: Curculionidae), and their parasitoids and predators. My hypothesis is that plant traits, such as extrafloral nectaries, that increase foraging by the natural enemies of these herbivores will decrease damage by herbivores and, ultimately, increase plant fitness.
Supplemental Keywords:
RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Geographic Area, Ecological Indicators, Ecosystem Protection, Ecology, Environmental Chemistry, Ecosystem/Assessment/Indicators, exploratory research environmental biology, Ecological Effects - Environmental Exposure & Risk, Ecological Effects - Human Health, Southwest, Chemical Mixtures - Environmental Exposure & Risk, Ecology and Ecosystems, Sonoran Desert, Bucculatrix thurberiella, ecosystem assessment, herbivores, natural enemies, cotton boll weevil, ecosystem, natural selection, Gossypium thurberi (Malvaceae), Anthonomus grandis, plants, cotton leaf perforator, agents of selection, direct plant resistance charactersProgress and Final Reports:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.