Calvin Luu
Honey bees are the most well-known pollinators, but there exists thousands of other bee species that contribute to pollination; one such group of bees are the solitary bees. True to their namesake, solitary bees do not live in hives like honey bees. Some solitary bees, like alfalfa leafcutting bees (ALCB) and blue orchard bees, can pollinate crops more efficiently than honey bees. However, since they live solitary lives, pesticide exposure is much more harmful to their overall population. If one honey bee dies from pesticide exposure, the hive can still survive, and the queen bee will continue producing offspring. If one female solitary bee dies, the lineage ends as she can no longer produce offspring. It is important to understand how pesticides move in the environment after they are applied to quantify pesticide exposures to solitary bees. In this work, I explore various aspects of pesticide transfer, persistence, and exposure to solitary bees. I investigated how pesticides can transfer from pesticide contaminated solitary bee nesting materials, like leaves and soil, into the solitary bee larval food called provisions. I measured how pesticides degrade under sunlight, how morning and evening pesticide applications affect how pesticides reduce in concentration over time, and used a prediction model to estimate pesticide concentrations in the field exposure to solitary bees. Lastly, I investigated how different pesticide application timing affects pesticide concentrations in the leaves, concentrations in the solitary bee nests, and the health and behavior outcomes for the ALCBs and their offspring.