Bumblebees may be small, only about an inch long, but they play a huge role in global agriculture. Approximately one-third of the world’s food production relies on pollinators such as bees. At the same time, these important insects face increasing pressure from pesticides and other environmental threats.
Modern pesticides are helping farmers protect crops and increase yields, but some can harm the pollinators that make large crops possible. One such chemical, sulfoxaflor, is a next-generation pesticide introduced in 2013 to control sap-sucking insects such as aphids on crops such as soybeans and corn. Although sulfoxaflor is effective against pests, it is also known to be toxic to bees. Scientists are now discovering how even low-level exposures affect bee reproduction at the molecular level.
Common pesticides alter gene activity in honey bees
Georgia Tech researchers found evidence that sulfoxaflor alters both gene activity and reproductive function in bumblebees. In the USDA-funded study, researchers exposed worker bees to low doses of insecticides before looking for changes in gene expression.
The most significant changes appeared in ovarian tissue, suggesting that pesticides may interfere with the reproductive process. Researchers say these genetic changes could reduce the number of offspring and cause honey bee populations to decline over time.
To investigate these effects, the researchers flash-frozen bee tissue and analyzed its RNA to measure how gene activity changed after pesticide exposure. They also used computational models to identify the biological systems most affected by the chemicals.
“What’s interesting about this study is that it links molecular changes in gene expression to real-world effects on individual bees and their colonies,” said Professor Michael Goodisman, from the School of Biological Sciences. “Such relationships are rare and give us a clearer picture of how pesticides affect bees.”
Balancing pest control and pollinator protection
The findings highlight an ongoing challenge in modern agriculture to protect crops from destructive pests without harming the beneficial insects that support food production.
“Pesticides are necessary to control crop pests, but they can also harm important non-target insects like bumblebees,” said Sarah Orr, who led the study as a postdoctoral fellow at Georgia Tech and is now an assistant professor at the University of Tampa. “My goal as a scientist is to identify practical solutions that support pest management while protecting beneficial insects and the food systems that depend on them.”
Orr emphasized that maintaining a healthy bee population is essential for successful pollination.
“It takes a lot of bees for successful pollination,” Orr says. “If you don’t leave enough offspring, pollination decreases.”
Bumblebees face multiple threats
Pesticides are just one of several challenges affecting bumblebees. Rising temperatures and increasing frequency of heat waves are further increasing stress on pollinators.
By better understanding how chemicals such as sulfoxaflor affect bee biology, researchers hope to develop farming practices that protect crops while protecting the pollinators on which many food systems depend.
