Biotic and Abiotic Mechanisms for the Maintenance of Variation in Flower Form of an Alpine Wildflower

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9508741 Gerhardt Explaining how genetic variation arises, is distributed among organisms, and is maintained over time is a major goal of evolutionary biology. Genetic variation in the characteristics that determine an organism's reproductive success is especially important, because it underlies the capacity of species to perpetuate themselves successfully under new environmental challenges. For animal-pollinated plants, one such attribute is flower form. Flower morphology is a complex trait that simultaneously influences plant resource use, the behavior of enemies, and the likelihood of pollination. This proposal addresses the environmental factors maintaining morphological variation in the flowers of one of the most abundant and ecologically dominant flowers of the Rocky Mountains, Polemonium viscosum. Specifically, experiments will test whether the large showy flowers preferred by animal pollinators exact a high cost in resources for future growth and survival and/or make plants more apparent and susceptible to flower predators. Such ecological tradeoffs could explain why genetic variation in flower form persists over time in P. viscosum and nearly every other natural and agricultural plant species that has been studied. Current farming expenditures on crop fertilization, irrigation and chemical pest management are considerable. The research described here could reduce such costs by suggesting how flower form can be genetically optimized to alleviate the amount of resource diverted from plant growth and the number of ovules lost to pest damage, while continuing to ensure adequate pollination. In this way, the proposed studies have the potential to make the cultivation of sunflowers, blueberries, strawberries, alfalfa and rapeseed, among myriad other animal-pollinated crops, more economical and environmentally sound.