2023 Undergraduate Research Showcase


Pollination Biology of a Rare and Threatened Endemic Plant: Evaluating the Floral Constancy of Astragalus mulfordiae Insect Visitors

Document Type

Student Presentation

Presentation Date


Faculty Sponsor

Dr. Ian Robertson


The biodiversity of our planet is in peril. Although this crisis impacts all organisms, it is especially concerning regarding plant-pollinator interactions. Flowering plants play a critical role for ecosystem functioning, human and animal nutrition, and offer much-needed habitat for many organisms. However, human impacts such as urbanization, climate change, unsustainable agriculture practices, and the spread of invasive plants, put these plants-and their pollinators-at risk. One such example is Astragalus mulfordiae, a rare and threatened plant endemic to southwestern Idaho. To learn more about the decline of A. mulfordiae and to develop effective conservation strategies, it is important to understand the pollinator relationships it relies on. This includes identifying which insects visit its flowers, and which are the most important for its pollination. Flower constancy is the tendency of individual pollinators to visit a single kind of flower, and pollinators with high flower constancy can be especially beneficial to plants by increasing the chances they receive pollen from their own species. In this project, we investigate whether insect species that visit A. mulfordiae flowers differ in their flower constancy. To evaluate this, we examined pollen collected off insects foraging at A. mulfordiae flowers. We first created a pollen reference library using pollen samples from surrounding plant species in A. mulfordiae habitat. We then used this library to identify the pollen grains on each insect, with flower constancy measured as the ratio of A. mulfordiae pollen to other pollen types. Our findings will provide insight into which insect species are most important for A. mulfordiae pollination and will help inform land managers who manage A. mulfordiae habitat areas.

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