Dissertation Research: The Consequence of Early Selection on Life History Evolution

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Selection operating at different points in the life cycle may ultimately limit or accelerate the pace of evolution, depending on how traits are linked across life stages. The research proposed here will examine the strength and direction of selection within and across life stages, focusing particularly on the delayed effects of selection early in the life cycle of an annual invasive plant, Agrostemma githago [Caryophyllaceae]. This will be addressed in a large-scale field experiment, in which the selective regime early in the life cycle is manipulated through the use of serial transplants. The experimental design is unique in facilitating a comparison of different selective regimes across the early life stages, while keeping late life environments constant across treatments. This research thus represents a novel way to assess how life histories are shaped and constrained through selective events taking place across the life cycle of a species. It will explore life history evolution in a natural population, and will account for temporal variation in selection. The results from this experiment will respond to longstanding questions in the fields of life history evolution and biodemography. By addressing which life stage is most critical to the success of an invading species, the results from this work will also be relevant to conservation efforts. The broader impacts of this research include an undergraduate research component for two undergraduate women currently working on projects related to this research.