Grantee Research Project Results

Effects of Introduced Plants on Native Phytophagous Insect Species

EPA Grant Number: U916220
Title: Effects of Introduced Plants on Native Phytophagous Insect Species
Investigators: Oliver, Jeffrey C.
Institution: University of Colorado at Boulder
EPA Project Officer: Packard, Benjamin H
Project Period: January 1, 2003 through January 1, 2006
Project Amount: $157,742
RFA: STAR Graduate Fellowships (2003) Recipients Lists
Research Category: Academic Fellowships , Biology/Life Sciences , Fellowship - Entomology

Objective:

The objective of this research project is to determine if introduced plants are, or have been, facilitating introgression between two native insect species. Many, if not all, terrestrial ecosystems have been altered by the introduction of exotic plants. Some native species have taken advantage of these changes, while other native species have been detrimentally affected. Putative hybrids of two butterfly species, Lycaena xanthoides and L. editha (Lepidoptera: Lycaenidae), occur in two regions of California, where nonnative Rumex (Polygonaceae) species have become established. Interestingly, the hybrid butterflies specialize on these nonnative species, whereas many populations of the parental species retain their associations with native Rumex and Polygonum(Polygonaceae) species.

Approach:

This research project will use historical records, analyses of molecular markers, oviposition preference and larval performance trials, and controlled interspecific crosses to test the hypothesis that nonnative Rumex species are facilitating introgression between two historically allopatric, genetically distinct butterfly lineages. Historical records, of host plants and insects, are available at herbaria and entomology museums, respectively. Distributions of native host plants, along with current distributions of the insects, will provide insight into the effect that introduced hosts have had upon the native insects' geographic ranges. Molecular marker analyses (direct sequencing of mitochondrial and nuclear genes, as well as Amplified Fragment Length Polymorphism analyses), will allow detection of recent demographic events, such as population expansion and gene flow. Female oviposition preference and larval performance trials assess the suitability of nonnative hosts relative to suitability of native hosts. Finally, laboratory crosses may measure the extent of potential gene flow and will aid in interpretation of the molecular marker analyses.

These combined analyses will allow me to assess the effects of introduced host plants on the species boundaries and genetic diversity of native phytophagous insects.

Supplemental Keywords:

fellowship, introduced plants, butterflies, Lycaena xanthoides, Lycaena editha, Rumex, Polyganum, phytophagous insect.

Progress and Final Reports:

2003

2004

Final