Date of Graduation

Summer 2026

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Avery Russell

Abstract

American elderberry (Sambucus nigra subsp. canadensis) is a woody deciduous shrub native to eastern North America. In addition to its long history of use by indigenous peoples, there is renewed interest in cultivating and consuming American elderberry, primarily driven by expanding health supplement markets. Despite recent advances in horticultural development of American elderberry, its pollination ecology remains poorly understood. In this field study, I evaluated the contribution of arthropod visitors to pollination of American elderberry. To do this, I first characterized the identities and abundances of arthropod visitors via timed arthropod collections and floral observations during peak flowering time. I then determined the relative importance of visitor taxa to pollen transport by counting the number of conspecific and heterospecific pollen grains carried in visitor pollen loads. Lastly, I assessed the absolute importance of arthropod visitation to pollination in terms of fruit set, fruit development, and fruit quality by excluding arthropods from flowers and comparing the resulting fruit with open-pollinated controls. A diverse assemblage of arthropods visited American elderberry flowers, comprising 11 orders and 46 families in total. Dipteran and Coleopteran groups were likely some of the most effective pollinators, with large, high-quality pollen loads; other groups with smaller pollen loads should not be discounted, however, as many of those with high-quality pollen loads and high abundances may have still contributed to pollination. Arthropod visitation improved pollination success in terms of ripe fruit set, although this pattern depended significantly on cultivar. Conversely, arthropod pollination did not impact fruit development or quality. Altogether, my results indicate arthropods can play a significant role in the pollination ecology of American elderberry but suggest there may be variation in pollination mode among cultivars.

Keywords

American elderberry, specialty crop, cultivar, pollination ecology, floral visitors, arthropods, pollinator exclusion, pollinator effectiveness, fruit set

Subject Categories

Botany | Entomology | Other Ecology and Evolutionary Biology | Plant Biology

Copyright

© Jenny K. Burrow

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