Sedgwick Reserve

30 Jun, 05 PM - 29 Jun, 05 PM

Abstract of funded NSF grant (2004-2007): The proposed work will assess how coevolving insects and plants diversify across complex continental landscapes as populations diverge in phenotypic traits and as an interaction spreads across multiple ecoregions. The work will evaluate the extent of geographic covariation in traits potentially important to a coevolving plant/insect interaction and the consequences of that variation for the geographic diversification of ecological outcomes (mutualism, commensalism, antagonism). Previous work has shown that the interaction between the pollinating seed-parasitic moth Greya politella and its major hostplant Lithophragma parviflorum spans the U.S. Rockies to coastal California. It is mutualistic in the post-Pleistocene populations of the northern U.S. Rockies, except in habitats where the interaction is swamped by co-pollinators. All populations within this region are similar in the morphological traits involved in the interaction and show relatively little molecular divergence. Over larger geographic scales, however, the moth and plant species are genetically and morphologically differentiated. The work will take advantage of four previous results that allow an assessment of how community context and divergence in phenotypic traits together shape the geographic mosaic of a coevolving interaction. First, floral traits unique to L. parviflorum differ geographically among the northern U.S. Rockies, coastal Oregon, and coastal California. Second, mitochondrial DNA haplotypes of G. politella match these regional differences in floral traits. Third, the morphologically unique traits of the moths also vary, allowing evaluation of whether this variation matches the regional differentiation in floral traits. Finally, the moths use a different hostplant, L. cymbalaria, at the southern edge of their range where their normal hostplant is rare. This outgroup comparison will allow evaluation of how absence of the unique traits found in L. parviflorum affects the interaction. Objective 1 will determine the extent to which the unique traits of G. politella covary geographically with the known large-scale geographic differences in floral morphology in Lithophragma. Objective 2 will evaluate how regional variation in plant and moth traits affects pollination efficacy, using experimental trials on sympatric and allopatric pairs of plants and moths. Objective 3 will assess whether the outcome of the interaction (mutualism, commensalism, antagonism) differs among regions through the combined effects of trait variation and community context (i.e., presence of local co-pollinators). The proposed work will therefore evaluate how the outcome of an interaction varies regionally as candidate traits potentially important for coevolution diversify against a background of different environments. Coevolutionary studies are the crucial ecological middle ground between analysis of the geographic structure of individual species and the biogeographic structure of species assemblages. The three objectives will provide a composite evaluation of how a widespread interspecific interaction has diversified across far western North America, crossing multiple ecoregions. The award will partially support two graduate students, the formal undergraduate research internship program within my laboratory, and our laboratory?s research goal of assessing how ongoing coevolution contributes to the overall organization of biodiversity across broad geographic landscapes. Work at Sedgwick. If needed, I would be very willing to send a copy of the Methods section of the NSF proposal. Briefly, the research at Sedgwick involves no large-scale manipulations of either the plants or the moths and no large-scale collections. We will collect up to a few dozen adult Greya moths from Sedgwick each year for use in pollination efficiency trials back in the greenhouse at UCSC. These moths will come from various locations around the reserve, with few moths coming from any one part of the reserve. We will also collect Lithophragma flowers and adult Greya moths for use in analyses of morphological traits that may affect pollination efficiency. We will also collect some moths and Lithophragma leaves for DNA analysis. We will collect only small number of plants and moths each year, because I do not want to affect the dynamics of these populations. Capsules will be collected from 50 plants distributed throughout Sedgwick to assess the effects of Greya oviposition on seed set. We will use the seeds from the capsules to grow plants in the greenhouse at UCSC. Sedgwick is the southernmost of four sites at which we will take the same measurements to evaluate the scale of local adaptation and geographic variation in the outcome of the interaction. The other sites occur in northern California, Oregon, and Washington State.

Visit #2384 @Sedgwick Reserve

Approved

Under Project # 1910 | Research

Geographic mosaics in diversifying plant/insect interactions

faculty - University of California, Santa Cruz

Reservation Members(s)

John Thompson Jun 30, 2003 - Jun 29, 2004 (366 days)
John Thompson Jun 30, 2003 - Jun 29, 2004 (366 days)
Group of 2 Research Scientist/Post Doc Jun 30, 2003 - Jun 29, 2004 (366 days)

Reserve Resources(s) | Create Invoice

Studio Apartment 4 Jun 30, 2003 - Jun 29, 2004