John N. Thompson - US grants

0083548
Parker
Biological invasions, acting in conjunction with climatic variability and spatial heterogeneity, are generating rapid ecological and evolutionary change in native ecosystems. Understanding how spatial and temporal dynamics shape the invasion process requires multiple integrated approaches. This project is designed to develop a consortium of natural and social scientists to advance our understanding of the current and future state of ecological systems in California. The consortium will combine two approaches. First, museum collections and historical data on invasions and climate will be analyzed and synthesized. Second, the group will coordinate monitoring and replicated experiments on the ways in which landscape context and climatic cycles shape the pulsed structure of invasions, rapid evolution within communities, food web and ecosystem dynamics, and regional patterns of biotic change. This research will lead to a practical and predictive understanding of environmental change and be of significant value to policy makers and resource managers.

0073911
Thompson
This project will investigate how coevolution shapes the interactions between insects and plants across broad geographic landscapes. A major current challenge in ecological research is to understand how ongoing coevolution proceeds as interacting species experience different selection pressures in different communities (co-evolutionary hotspots). The combined ecological, geographic, and phylogenetic evidence allows the opportunity to use the interactions between the moth Greya politella and its host plants to address these central questions on co-evolutionary processes. The moths are locally host specific pollinating seed parasites, and the interaction between the moths and their host plants occurs across a wide range of habitats in western North America. Three objectives will be addressed in this study. The first objective is to determine whether the differences in outcome among communities are stable over time, and the second objective will assess whether the geographic patterns in outcome result from gene flow among populations in different communities. The third objective will be to evaluate how the differences in the interaction between the mutualistic and antagonistic hotspots identified during previous work contribute to the different ecological outcomes. Together, the results of these three objectives will aid in the development of the theory of coevolution and the organization of biodiversity. They will address how selection mosaics and co-evolutionary hotspots shape species interactions across geographic landscapes under different ecological conditions. Overall, the results will therefore contribute to our understanding of the geographic scale at which interspecific interactions diversity and the ways in which coevolution links taxa among communities.

0116278
Zehr
This Major Research Instrumentation award to University of California Santa Cruz will provide support for acquisition of a genetic analyzer for DNA sequencing, liquid handling robotics, computer workstations and software for DNA analysis, and technical support for the Molecular Ecology and Evolutionary Genetics facility. It is expected that the new instrumentation and the interdepartmental research and training facility will foster interdisciplinary approaches to a broad range of problems in marine and terrestrial ecology and evolutionary biology. UCSC will contribute cost-sharing of more than 30% of the cost of this project from non-federal funds.
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Work on this award will evaluate how the process of coevolution shapes interactions between insects and plants over large geographic scales. Many interactions between plants and their herbivores and pollinators occur across multiple ecoregions. These interactions evolve in different ways in different regions, but they are connected by movement of individuals among populations. The purpose of this award is to understand how the large-scale structure of these interactions develops amid this geographic mosaic of coevolution. The results will contribute to our understanding of how biodiversity is organized over large geographic scales, and how interactions between species may persist in a constantly changing world. The results will therefore contribute to our understanding of how best to conserve the earth's biodiversity through efforts at regional and continental scales.

The research will use the moth Greya politella and its major hostplant Lithophragma parviflorum. These species range from the U.S. Rockies to coastal California. This is one of the most widely-distributed interactions between plants and insects in western North America. The traits of the species, the ecological outcomes of the interaction between them, and the genetic structure of the populations are already known from past work to vary regionally. The species can also be easily manipulated in the field, laboratory, and greenhouse. This interaction therefore provides a useful model for analyses of the geographic mosaic of coevolution.

Coevolution - the process by which interacting species undergo reciprocal evolutionary change - is one of the major driving forces underlying the generation and maintenance of biodiversity. Research over the past decade has shown that spatial heterogeneity can influence coevolutionary interactions. However, a complete, mechanistic understanding of the influence of spatial heterogeneity on coevolution is still needed.
The proposed research combines theoretical and empirical approaches to rigorously evaluate how spatial heterogeneity in resource availability and dispersal among habitat patches influence coevolution. It utilizes the bacterium Escherichia coli and the bacteriophage T7, a viral parasitoid of E. coli, as model coevolving organisms. Experiments in which dispersal and resource availability are directly manipulated will be combined with theoretical models that incorporate details of the host-parasitoid interaction to provide both qualitative and quantitative predictions of how dispersal across a heterogeneous landscape influences coevolution. This research provides a crucial middle ground between the relative simplicity of current mathematical models and the complexity of field studies. This research will add to our understanding of the geographic mosaic theory of coevolution and metacommunity theory, which underlie much of the work on habitat fragmentation in conservation biology. This work will also increase our understanding of coevolving microbes, which perform many crucial ecosystem services and which have been vastly understudied. Finally, the research will contribute to our general knowledge of how spatial heterogeneity influences the ecology and evolution of interacting organisms.

A current challenge in coevolutionary biology and community ecology is to understand how networks of interacting species evolve in different ways in different environments. The importance of this challenge is increasing, as the species composition of many ecosystems is rapidly changing worldwide. We need to understand the extent to which the interactions between networks of species can change under different ecological conditions and how those changes may be structured genetically by the phylogenetic history of lineages. The proposed work will evaluate how networks of interacting plants and insects differ in structure across geographic landscapes as populations evolve and diverge. The work will focus on the specific problem of how a four-species network of two closely-related plant species and two closely-related moth species differ genetically and ecologically in four environments in California. Objective 1 will evaluate how the moths Greya politella and G. obscura (Prodoxidae) differ along the Coast Ranges of California in their use of the woodland stars, Lithophragma parviflorum and L. heterophyllum (Saxifragaceae). Objective 2 will evaluate whether differences among habitats in how moths use these two plant species are determined genetically or by local ecological conditions. Objective 3 will use molecular markers to assess whether similarity in network structure among some habitats results from the shared phylogenetic history of those populations.

Overall, the integration of ecological and molecular approaches in the proposed work will provide a direct evaluation of how the diversification of lineages and local ecological conditions collectively contribute to geographic differences in the organization of biological communities. This research will also aid in training undergraduate students in all aspects of scientific research. Undergraduate students will gain molecular, greenhouse, and field skills while learning about experimental design, data analysis, and manuscript preparation. Results of this work will be presented at national meetings.

This project will analyze how coevolution between plants and insects shapes the web of interactions among species in contrasting ecosystems. This project will address one of the current major challenges in biology, which is how and why the same groups of species interact in different ways in different ecosystems. The specific goal is to understand how groups of interacting species diverge genetically and ecologically as they coevolve and expand their geographic ranges into new environments. The study will use interactions between a group of common plant species in western North America and a group of insect species that are the major herbivores and pollinators of those plants. DNA sequencing and related molecular methods will be used to evaluate how populations of these interacting species are genetically connected across ecosystems. The second part of the work will combine field observations of the use of flowers by the different insect species with measurements of floral morphology to assess whether the traits of these interacting plants and animals differ geographically. This will provide a test of the geographic mosaic theory of coevolution, which predicts that the strength of matching of floral trait to insect species varies with the presence of competing species of both the plant and insect. The third part of the work will use laboratory experiments to quantify the mechanisms by which natural selection shapes floral traits differently in the different ecosystems.

Collectively, these genetic and ecological studies will contribute to a broader understanding of how the web of life is organized spatially across ecosystems, and whether there are predictable patterns in how networks of interacting species change under different environmental conditions. A deeper understanding of the organization of species networks is crucial to predicting the consequences of climate change, and to conserving and restoring the biological integrity of ecosystems. This award will also support the training of graduate and undergraduate students and a postdoctoral fellow in interdisciplinary research at the interface of ecology and evolution.

This project will synthesize several decades of research on how environmental change affects the genetic structure of species and interactions among species. The synthesis will draw from a wide range of studies on interactions between parasites and hosts, predators and prey, competing species, and mutualistic species. The goal is to understand how ecological and evolutionary processes alter webs of interacting species amid environmental change. The synthesis will be published as a book that will summarize the findings.

The project is timely, because there is a growing scientific and societal need to understand how environmental change, including habitat fragmentation, spread of invasive species, and extinction of species, may be altering the evolution of species and their interactions with each other. Toward that end, the synthesis will include an analysis of how the accelerating pace of environmental change may be affecting the process of natural selection on the traits of species and on interactions among species. By evaluating current hypotheses and predictions, this synthesis therefore should help identify some of the most fruitful directions for future research on how changes in physical environments and biological communities foster genetic change in populations and species. In addition to publication of the scientific findings, the principal investigator is involved in multiple mentoring roles and outreach programs that will provide ways of disseminating the findings to a broader audience.