"Assessing the Effects of Non-Native Flowering Plants and Anti-Herbivor" by Emily Renee Sun

Publication Date

12-2023

Date of Final Oral Examination (Defense)

October 2023

Type of Culminating Activity

Thesis

Degree Title

Master of Science in Biology

Department Filter

Biology

Department

Biological Sciences

Supervisory Committee Chair

Ian C. Robertson, Ph.D.

Supervisory Committee Co-Chair

David S. Pilliod, Ph.D.

Supervisory Committee Member

James H. Smith, Ph.D.

Abstract

Bees (Hymenoptera: Apoidea) are among the most prominent pollinators of the flowering plants and play an essential role in maintaining ecosystem function. Disruption of plant-pollinator interactions is a growing global concern because of the implications for biodiversity, ecosystem health, and agriculture. The incursion of non-native plants globally is seen to adversely affect native plants and alter plant-pollinator communities. In chapter one, I examined the effects of a non-native weed, Sisymbrium altissimum (tall tumblemustard), on bee visitation to nearby native Sphaeralcea munroana (Munro’s globemallow), including genera-specific differences among bees. The most common bee genera were Andrena, Colletes, Diadasia, Halictus, and Lasioglossum. I found that bees carried pollen from both tumblemustard and globemallow, suggesting that bees were foraging at both plant species. I found little evidence to support my hypothesis that non-native tumblemustard would positively affect bee visitation by providing supplemental floral resources and attracting bees to an area. Instead, in general, more bees visited the native globemallow than tumblemustard and the number of bee visits was positively associated with the number of globemallow blooms but not tumblemustard. Some generalist bees, such as Andrena and Lasioglossum, increased visitation in response to tumblemustard blooms, while Halictus were only associated with globemallow blooms. Specialists, like Colletes and Diadasia, increased visitation with globemallow blooms and were only seen foraging at globemallow at the plots. Although this study did not show strong effects of tumblemustard abundance either positively or negatively affecting bee abundance to nearby plants, at least some bees, notably generalists like Andrena and Lasioglossum utilize these non-native plants and may benefit from their presence.

In chapter two, I investigated whether Vexar®, an anti-herbivory plastic tube used in restoration planting, prevents bees from visiting flowers. Planting nursery-raised forb seedlings in restoration projects is increasing in sagebrush steppe, especially following disturbances such as wildfire. Forbs provide important resources for wildlife and pollinators. I wanted to understand whether these commonly used anti-herbivory tubes have deterrent effects on bees, through physical exclusion, visual deterrence, or both. To test these possibilities, I altered the presence and color of Vexar protecting two native plant species, Munro’s globemallow and shaggy fleabane (Erigeron pumilus), and observed the visitation rates of bees to flowers in a controlled field setting. I also examined the spectral signatures produced by Vexar painted in different colors and related this information to the color spectrum detected by bees. I found that Vexar did not create a physical barrier for bees (i.e., preventing bees from visiting the flowers inside) as visitation was comparable across treatments. My spectral analysis suggested that Vexar does not interfere with the bees’ ability to detect the flowers, but asking manufacturers to use blue- or yellow-dyed plastics may attract more bees. Future work regarding both of these experiments should include measurements of native plant seed set to elucidate whether tumblemustard or Vexar interfere with native plant pollination success.

DOI

https://doi.org/10.18122/td.2198.boisestate

Included in

Biology Commons

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