Is glyphosate killing honeybees?

According to a new research, the most used weedkiller destroys the beneficial bacteria in the guts of honeybees and exposes them to deadly infections. We already knew that some pesticides, such as neonicotinoids, are really dangerous to the bees, while these little animals are fundamental in our economies: theirs pollination is essential to about three-quarters of all food crops. 

Glyphosate made by Monsanto aim an enzyme only found in plants and bacteria. But the researchers claimed that glyphosate damages the microbiota that are indispensable to bees’ growth and disease fighting. So glyphosate may be destroying bees around the world. 

«We demonstrated that the abundances of dominant gut microbiota species are decreased in bees exposed to glyphosate at concentrations documented in the environment» said Erick Motta and colleagues from University of Texas at Austin in their new paper. In the research, they explain how young worker bees exposed to glyphosate died more often when later exposed to a common bacterium.

In July another research was published in China. It found that honeybee larvae grew more slowly and died more often with glyphosate exposure. Moreover, a 2015 study already explained that the exposure of adult bees to the herbicide at levels found in fields «impairs the cognitive capacities needed for a successful return to the hive».

«The biggest impact of glyphosate on bees is the destruction of the wildflowers on which they depend» said Matt Sharlow, at conservation group Buglife. «Evidence to date suggests direct toxicity to bees is fairly low, however the new study clearly demonstrates that pesticide use can have significant unintended consequences», Sharlow claimed. 

Prof Dave Goulson, at the University of Sussex, said: «It now seems that we have to add glyphosate to the list of problems that bees face. This study is also further evidence that the landscape-scale application of large quantities of pesticides has negative consequences that are often hard to predict». 

However, Oliver Jones, a chemist at RMIT University in Melbourne, Australia, said: «To my mind the doses of glyphosate used were rather high. The paper shows only that glyphosate can potentially interfere with the bacteria in the bee gut, not that it actually does so in the environment». 

Also a spokesman for Monsanto said something on this issue: «Claims that glyphosate has a negative impact on honey bees are simply not true. No large-scale study has found any link between glyphosate and the decline of the honeybee population. More than 40 years of robust, independent scientific evidence shows that it poses no unreasonable risk for humans, animal, and the environment generally». 

The research came after an US court’s order to Monsanto to pay 289 million dollar in damages since a jury ruled that the weedkiller caused a man’s cancer. Indeed, we consume lots of glyphosate residues in food but the health impact is controversial.