New research into the link between bee death and pesticides bolsters calls 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 U.S. have fallen by as much as 43% in areas with high pesticide use, versus areas where no pesticides are used.
While data is mixed on the status of the more recognizable honeybee, which was brought to the Americas by European colonizers in the 17th century, the decline of native pollinators is evident; about a quarter of wild bee species are “imperiled and at increasing risk of extinction,” according to a 2017 study by the nonprofit Center for Biological Diversity, which cited habitat loss and pesticide use as the primary threats, along with climate change and urbanization.
To better understand the interaction between pesticides and native bees, the USC researchers analyzed 178,589 observations of 1,081 wild bee species, pulling from museum records, ecological surveys, and community science data, as well as governmental land and county-level pesticide surveys. For wild bees, the researchers found that the “negative effects of pesticides are widespread,” and the rise in use of two common pesticides, neonicotinoid and pyrethroid, “is a major driver of changes in occupancy across hundreds of wild bee species.”
The study points to alternative methods of pest control as a means of protecting the pollinators and the vital role they play in ecosystems and food systems. Such alternatives include mitigating pests with natural predators and using traps and barriers before resorting to pesticides.
Some research suggests that competition for pollen from honeybees is harmful for native bees, but the new USC study didn’t find a noteworthy connection there, with lead research and USC professor of biological sciences and quantitative and computational biology Laura Melissa Guzman acknowledging that more study is needed to back this up.
“While our calculations are sophisticated, much of the spatial and temporal data is coarse,” 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 harmful for humans, too. The EPA has found that some pesticides—organophosphates and carbamates in particular—can affect the body’s nervous system, while others can impact the endocrine system. Around 1 billion pounds of pesticides are used in the U.S. annually, per a 2017 Ohio-Kentucky-Indiana Water Science Center study. Consumer Reports said in April that it found risky levels of pesticides in 20% of produce in the U.S.