Our pest control is killing the bees

New research on the link between bee mortality and pesticides is reinforcing the call for alternative pest control methods. According to a peer-reviewed study published in Nature Sustainability by researchers at the University of Southern California Dornsife, wild bee sightings in the United States have declined by as much as 43% in areas with high pesticide use, compared to areas where no pesticides are used.

While data is mixed on the status of the better-known honey bee, brought to the Americas by European colonialists in the 17th century, the decline of native pollinators is evident: About a quarter of wild bee species are “endangered and increasingly at risk of extinction,” according to a 2017 study by the nonprofit Center for Biological Diversity. Habitat loss and pesticide use were cited as the biggest threats, along with climate change and urbanization.

To better understand the interaction between pesticides and native bees, USC researchers analyzed 178,589 observations of 1,081 wild bee species, using museum records, ecological and community science surveys, and state and county pesticide surveys. For wild bees, researchers found that the “negative impacts of pesticides are widespread” and that the increase in the use of two common pesticides, neonicotinoids and pyrethroids, “is a major driver of population changes in hundreds of wild bee species.”

The study points to alternative methods of pest control as a means of protecting pollinators and their important role in ecosystems and food systems. These alternatives include controlling pests through natural predators and using traps and barriers before applying pesticides.

Some research suggests that honeybees' competition for pollen is harmful to native bees, but the new USC study found no significant link. Lead researcher and USC professor of biological sciences and quantitative and computational biology Laura Melissa Guzman acknowledged that more studies are needed to support this assumption.

“Although our calculations are sophisticated, much of the spatial and temporal data is rough,” Guzman acknowledged in a university press release. The researcher added: “We plan to refine our analysis and fill in the gaps as much as possible.”

High pesticide use is also harmful to humans. The EPA has found that some pesticides — particularly organophosphates and carbamates — can affect the body's nervous system, while others can affect the endocrine system. About 1 billion pounds of pesticides are used annually in the U.S., according to a 2017 study by the Ohio-Kentucky-Indiana Water Science Center. Consumer Reports said in April that it had found risky levels of pesticides in 20% of products in the U.S.