Date of Graduation

Spring 5-15-2026

Document Type

Thesis

Degree Name

Master of Science in Biology

College/School

College of Arts and Sciences

Department/Program

Biology

First Advisor

Dr. Sevan Suni

Second Advisor

Dr. James Sikes

Third Advisor

Dr. John Paul

Abstract

Plants must receive pollen from the same species in order to successfully reproduce. For most flowering plants, the transfer of pollen occurs via animal pollinators while they forage on plants to obtain food. Therefore, the fidelity of pollinators to individual plant species during foraging trips is directly related to the amount of conspecific pollen plants receive. Low floral fidelity of pollinators can reduce plant reproductive success, which in turn has the potential to lower food resources for pollinators in the future. While many factors can potentially influence pollinator floral fidelity, several important ones may be the nutritional resources provided by plants, competition from other pollinators, urbanization, and climatic seasonality. This master’s thesis describes an investigation of ecological drivers of floral fidelity and mechanisms underlying variation in those drivers. We investigated if pollen protein content, managed honey bee presence, or landscape factors associated with urbanization affect pollinator floral fidelity. Floral fidelity was higher at sites with less natural habitat and with lower plant species richness and increased over the growing season as the plant species richness at sites decreased. Floral fidelity was higher to plant species that had higher pollen protein content overall, but this effect was evident only for wild pollinators and not for honey bees. In addition, floral fidelity to plants with high protein content increased with decreasing natural habitat. There was no effect of managed honey bee hive presence on floral fidelity, but pollinators foraged on plants with higher protein content at sites with managed hives.  These findings show that both landscape-level and nutritional factors influence floral fidelity, and they suggest that under less-optimal conditions, pollinators may be more likely to continue foraging on the same plant species. In addition, they suggest that hive presence can shift wild pollinator foraging choices toward higher-protein pollen sources. Furthermore, variation among pollinator species in the extent to which pollen protein content drives floral fidelity suggests a mechanism by which plant species coexistence may occur, as well as a potentially useful way to support pollinator populations. That is, augmenting habitat with high-protein plants could potentially offset competition from managed honey bees as well as the negative effects of urbanization on wild pollinators.

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