Researchers at the University of Texas at Austin recently discovered bees “lose some of the beneficial bacteria in their guts and are more susceptible to infection and death from harmful bacteria” when exposed to a popular herbicide called glyphosate.
A study, published this week in the “Proceedings of the National Academy of Sciences,”describes the method scientists used to draw that conclusion.
“The researchers exposed honey bees to glyphosate at levels known to occur in crop fields, yards and roadsides. The researchers painted the bees’ backs with colored dots so they could be tracked and later recaptured,” UT Austin said in a statement.
Glyphosate was found to have “significantly reduced healthy gut microbiota” when scientists looked after three days.
The study examined how bees were affected when they were faced with a type of pathogen called Serratia marcescens, too.
“About half of bees with a healthy microbiome were still alive eight days after exposure to the pathogen, while only about a tenth of bees whose microbiomes had been altered by exposure to the herbicide were still alive,” the school explained.
Erik Motta, a graduate student who co-led the project, called for improved protocols.
“We need better guidelines for glyphosate use, especially regarding bee exposure, because right now the guidelines assume bees are not harmed by the herbicide,” he said in a statement. “Our study shows that’s not true.”
The school says glyphosate is possibly “indirectly killing bees.”
But Monsanto — whose product Roundup contains the herbicide — has denied that glyphosate is harmful to them.
“Claims that glyphosate has a negative impact on honey bees are simply not true,” a spokesman for the company told The Guardian. “No large-scale study has found any link between glyphosate and the decline of the honeybee population.”
The representative added, “More than 40 years of robust, independent scientific evidence shows that it poses no unreasonable risk for humans, animal, and the environment generally.”