A new study suggests that glyphosate, the active ingredient in Monsanto’s Roundup weed killer, could be contributing to the decline of the global honeybee population.
The research, which was published in the journal Proceedings of the National Academy of Sciences, found that honeybees exposed to glyphosate lose some of the beneficial bacteria in their guts, which makes the insects more vulnerable to infection and death from harmful bacteria.
For the study, the research team exposed honeybees to glyphosate at levels known to occur in crop fields, yards and roadsides. The insects’ backs were painted with colored dots so they could be tracked and later recaptured.
Within 3 days, glyphosate had significantly reduced healthy gut microbiota in the exposed bees. The bees with reduced gut microbiota were also more likely to die.
“Studies in humans, bees and other animals have shown that the gut microbiome is a stable community that resists infection by opportunistic invaders,” said Nancy Moran, a professor at the University of Texas at Austin and co-lead author on the study. “So, if you disrupt the normal, stable community, you are more susceptible to this invasion of pathogens.”
She and her fellow authors recommend that farmers, landscapers, and homeowners avoid spraying herbicides containing glyphosate on flowering plants that bees are likely to visit.
Of course, Bayer – which recently acquired Monsanto – disputes the study’s findings.
Monsanto’s Roundup is the world’s most popular weed killer.
However, in 2015, the World Health Organization’s International Agency for Research on Cancer (IARC) declared glyphosate a “probable human carcinogen”. In particular, the IARC review suggested a link between glyphosate exposure and non-Hodgkin’s lymphoma, including its various subtypes.
More than 8,000 Roundup lawsuits have been filed in court throughout the country that accuse Monsanto of concealing the alleged link between glyphosate.
In August, a San Francisco Superior Court jury awarded $289 million in compensatory and punitive damages to a former school groundskeeper who was exposed to Monsanto’s glyphosate-based weed killers, including Roundup, 20-to-30 timers per year during his career.
Dwayne Johnson, the 46-year-old plaintiff in that case, was diagnosed with non-Hodgkin’s lymphoma in 2014 and is now considered terminal.
The case was the first Monsanto Roundup cancer lawsuit to go to trial anywhere in the United States. Bayer – which recently acquired Monsanto – is appealing the verdict.