Document Type
Honors Project
Publication Date
6-13-2025
Abstract
The interaction network between pollinators, plants, and the microbes that inhabit them is not yet widely understood. Most studies of floral microbes have focused on the role of nectar yeasts (e.g., Metschnikowia reukaufii) in the behavior of bumble bee pollinators and how they affect the fitness of plant subjects. However, little is known about the effects of these microbes on the hummingbird-pollinated wildflower Ipomopsis aggregata. To gain further understanding of this interaction, a full factorial experimental design with two treatment levels was employed: supplementation with sterile vs. M. reukaufii-inoculated nectar analogue and artificial nectar robbing vs. no nectar robbing. Fluorescent quantum dots were used to quantify how these factors affected the dispersal of pollen grains from donor plants by comparing pollen donation across the four plant treatments. The results suggest potential male fitness advantage on unrobbed plants, evidenced by significantly higher pollen donation from unrobbed donor plants to neighboring individuals. The presence of yeast in plants showed slightly lower pollen donation respective to the presence of robbing, however the trend did not display statistical significance. This indicates that the absence of nectar robbing in I. aggregata, but not the presence of yeast or lack-there-of, may promote outcrossing, impacting hummingbird visitation and pollen dispersal. These findings imply that, not nectar yeasts, but nectar robbing decrease the male fitness of the hummingbird-pollinated I. aggregata plant.
Level of Honors
cum laude
Department
Biology
Advisor
Alyssa Hakes
Recommended Citation
Thoresen, Greta, "Fit or Unlit: Using Quantum Dots to Investigate the Effects of a Floral Yeast and Nectar Robbing on Male Fitness in Ipomopsis aggregata" (2025). Lawrence University Honors Projects. 206.
https://lux.lawrence.edu/luhp/206