Widespread use of pesticides may be contributing to the sudden decline of wild honeybee populations, according to a new study.
There are many reasons for the decline of the world's honeybee population, but a surge in the use of two specific pesticides is particularly contributing to the trend, according to a study published Tuesday. Natural sustainability.
Two compounds, neonicotinoids and pyrethroids, are “major drivers of population change in hundreds of wild bee species,” the authors explained.
For certain species, the changes can be so pronounced that studies have shown that heavy pesticide use contributes to a 43.3 percent decrease in the likelihood that a species will occur in a particular location.
To reach their conclusions, a research team led by the University of Southern California examined museum records, ecological surveys, and community science data from across the continental United States collected between 1996 and 2015.
The team then scrutinized more than 200,000 individual observations of more than 1,000 species of honeybees, roughly one-third of all known honeybee species in the United States, to determine how frequently different species occur in different locations.
Along with these assessments, the researchers also analyzed government data on crop cover types and county-level pesticide applications.
“We found that increased pesticide use has led to declines in wild honeybee occupancy across the continental United States,” the researchers wrote. “The negative effects of pesticide use were common to all five honeybee families.”
The authors cited their findings as a compelling argument in favor of alternative pest control strategies.
They particularly highlighted the benefits of integrated pest management, including the deployment of natural enemies, proactive efforts to reduce pest establishment, and physical traps and barriers.
The new findings build on earlier research led by the same team, which identified flaws in current ecological risk assessments of pesticides and honeybees.
The study found that these assessments, which typically rely on invasive honeybees as a proxy for all bees, underestimate the threat to wild bees by a million times.
“Focusing only on the Western honeybee ignores the unique responses of other wild honeybee species to pesticide exposure,” said Laura Melissa Guzman, an assistant professor of biological sciences at USC and lead author of the paper. It said in a statement.
“Increasing data and analysis on the long-term effects of pesticides will advance efforts that benefit all pollinators, including wild bees,” she added.
