The Surprising Habits of Bumblebee Queens in Hibernation
When searching for the perfect winter retreat, bumblebee queens are drawn to specific environmental features: north-facing, sloping ground with loose, sandy soil. These attributes are ideal for hibernation, but recent scientific findings have revealed an unexpected preference: pesticides.
In a groundbreaking study published last month in the journal Science of The Total Environment, researchers conducted an experiment to observe the hibernation choices of common eastern bumblebee queens. They provided these insects with a choice between clean soil and soil contaminated with various pesticides. The results were astonishing and counterintuitive.
Sabrina Rondeau, an ecologist at the University of Ottawa, noted, “Queens did not avoid any of the pesticides.” This was particularly surprising because even at high concentrations, the bumblebee queens exhibited a preference for the pesticide-laden soil. Dr. Rondeau admitted, “The finding was very surprising.”
Another researcher, S. Hollis Woodard, a bee biologist at the University of California, Riverside, described the implications of this study as “terrifying.” She explained, “It wasn’t just one pesticide at one concentration; it was across the board.” This raises alarms since our soils are heavily contaminated with pesticides, many of which have spread far beyond their original application sites. By gravitating toward these toxic substances, the queens may expose themselves to significant risks and potential harm.
Bumblebees, with their approximately 250 species, generally follow an annual life cycle. In spring, mated queens emerge to establish new colonies, which thrive throughout the summer. By fall, these colonies die off, leaving only the queens to survive the winter. As the cold months approach, these queens burrow into the soil to endure the frigid conditions before restarting the cycle in the spring.
This solitary period of a queen’s life is not well understood. Dr. Woodard pointed out, “There’s a huge bias in bumblebee research that favors the social stage of a bustling bumblebee colony.” However, she emphasized, “For much of the year, queens are living their own little solitary lives.” Understanding their hibernation preferences and behaviors is crucial for the conservation of these essential pollinators.
