The study, led by researchers at the University of California, Berkeley, focused on a naturally occurring compound found in the leaves of the common milkweed plant. This compound, called “cardenolide,” has been shown to have insecticidal properties in previous studies. The researchers found that cardenolides effectively reduced the toxicity of pesticides, particularly those containing neonicotinoids, which are widely used in agriculture.
The study found that when the microparticles were fed to bumblebees in sugar water, they led to 30% higher survival rates in bumblebees exposed to lethal doses of neonicotinoids, and significantly lessened symptoms in bumblebees exposed to sub-lethal doses of the chemical. The antidote has the potential to be selectively applied to other pesticides, including widely used organophosphates. “Bees are crucial for crop pollination and agriculture, and food security, so it’s important for people to take bee health seriously,” said Julia Caserto, Ph.D. ’24, the paper’s first author and a former member of the lab of Minglin Ma, professor of biological and environmental engineering in the College of Agriculture and Life Sciences and the paper’s corresponding author.
Eliminating pesticides altogether would be a good goal, but may not be fully realistic, Caserto said: “We want to try and overcome these pesticide exposures in managed bees so that we can still have sufficient crop pollination for us all to be sustainable.” Neonicotinoids get into groundwater and can be soaked up by plants, entering pollen and nectar. When bees draw nectar, they can be exposed to the pesticide, which specifically targets insect receptors. Bees also bring contaminated pollen back to hives. In sublethal doses, neonicotinoids affect the bee’s mitochondria, the cell organelle where energy is produced, and they can affect the transfer of energy in bees, inhibiting movement and flight. They also compromise bee immunity, making them more susceptible to mites and viruses.
This finding suggests that microparticles could be a promising strategy for mitigating the negative impacts of neonicotinoids on bumblebees. The study also found that microparticles could potentially reduce the amount of neonicotinoid absorbed by bumblebees. The study’s findings are significant because they provide evidence that microparticles could be a viable alternative to traditional methods of mitigating neonicotinoid toxicity in bumblebees.
This approach would allow for a more targeted and efficient delivery of the antidote, minimizing the risk of contamination and ensuring its effectiveness. This method also aligns with the current practices of beekeepers, who already use supplements to improve bee health. Furthermore, the development of a microparticle-based antidote could potentially lead to the development of other microparticle-based treatments for various bee diseases.
The study was supported by the New York State Environmental Protection Fund and the U.S. Department of Agriculture.
