Pollinator populations are declining globally due to multiple interacting stressors, including poor nutrition, pesticide exposure, habitat fragmentation, invasive species, and emerging pathogens and parasites. These stressors may act synergistically, producing combined effects more harmful than each alone. Despite growing concern, few studies have examined how poor nutrition and pesticide exposure interact to affect bumblebee health. Understanding how the timing of floral resource abundance shapes resilience to chemical stressors is critical for supporting pollinator populations in increasingly disturbed and agricultural landscapes. My research investigates the interactive effects of diet and chronic pesticide exposure on bumblebee health and detoxification responses. This work seeks to identify nutritional strategies to enhance pesticide resilience and inform pollinator-focused restoration efforts in post-agricultural landscapes.
A Bombus nevadensis queen foraging on Astragalus spp. (milkvetch).
A Bombus huntii queen foraging on Astragalus spp. (milkvetch).
A look inside the rearing room this summer! Bumblebee colonies have to be reared in the dark under very specific conditions. Here is a photo of some of the wild queens that have been caught.
I am currently rearing colonies produced from wild-caught bumblebee queens in a laboratory setting! From these colonies, I will be producing microcolonies to address my research questions. A bumblebee microcolony is formed when five workers from the same natal colony are placed together. In the absence of a queen, one of the workers will essentially become a "pseudoqueen", develop her ovaries, and begin laying eggs. Since bumblebees have a haplodiploidy sex determination (i.e. fertilized eggs become females, unfertilized eggs become males), microcolonies can only produce drones (male bumblebees). Microcolonies, of course with limitations, can serve as a proxy for how bumblebees may respond to different conditions in a controlled laboratory environment.
Neonicotinoids are a class of insecticide that is widely used across the United States. The three most common neonicotinoids in the United States are clothianidin, imidacloprid, and thiamethoxam. Commonly applied as a seed coat, neonicotinoids are water-soluble, meaning they can easily travel through soil and plant tissue, including nectar and pollen. Neonicotinoids persist long after their first application, commonly being detected months to years afterwards. Neonicotinoids target and compromise the nervous system of insects, posing a huge threat to our native pollinators. In bumblebees, neonicotinoids have been shown to cause decreased foraging activity, impaired learning behavior, decreased brood care, lethargy, and ultimately death. For this reason, it is vital to understand how we can better protect our native pollinators, such as bumblebees, from neonicotinoid exposure.
Neonicotinoid diagram from Rodríguez‐Hernández et al. 2023.