Scientists warn that glyphosate, a weed killer, kills bees

Scientists say a commonly used weed killer can destroy bee populations around the world.

According to researchers at the University of Texas at Austin, glyphosate appears to destroy the so-called good bacteria in honey bee intestines, leaving insects more vulnerable to infection and even death.

The weed killer works by attacking an enzyme in a particular pathway found in plants and in some microorganisms, but it is not thought to harm animals such as bees.

However, in a study published in the journal Proceedings of the National Academy of SciencesThe researchers speculated that glyphosate can kill microorganisms, which could also damage a bee's microbiome. The microbiome is the term used to describe the bacteria that inhabit the interior and exterior of living organisms, including humans, and that it is believed to play a vital role in maintaining health .

Scientists are trying to understand why honey bee populations are depleting. Getty Images

The authors of the study urged decision-makers to develop better guidelines for the use of glyphosate and called on those who use products containing this product, from farmers to home gardeners, to stop with plants whose the bees could collect the nectar.

"Right now, the guidelines assume that the herbicide does not harm bees," said Erick Motta, a graduate student who led the study. "Our study shows that this is not true."

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To study the role that the weed killer plays in the depletion of bee populations, the researchers collected bees with established intestinal microbiota. They measured the insects with glyphosate at levels equal to those found in the cultures and tagged them to be able to find and recover them. They repeated their experiments on bees from another hive.

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Scientists took DNA samples from the bowels of bees. After three days, the researchers discovered that glyphosate had killed good bacteria in the digestive system of bees. This included Snodgrassella alvi, which the authors described as "the main species of bees".

While bees with healthy microbiomes could fight Serratia marcescens, a common pathogen that infects bees, the researchers found that people with good impoverished bacteria were more likely to die when they came in contact. Half of the healthy bees survived after exposure to the pathogen, compared to one-tenth of the bees that received glyphosate.

Dr. Nancy Moran, professor of integrative biology at the University of Texas at Austin College of Natural Sciences who co-directed the study, said, "Studies in humans, bees, and other animals have showed that the intestinal microbiome infection by opportunistic invaders. So, if you disrupt the normal and stable community, you are more susceptible to this invasion of pathogens. "

This is the most recent study to try to determine why bee populations are dying, a trend that could devastate global agricultural production. For example, between 2016 and 2017, US beekeepers lost 33% of their bee populations, according to the University of Maryland and Bee Informed. And over the last decade, beekeepers and scientists have tackled a disease known as colony collapse disorder.

In April 2018, the European Union banned the use of neonicotinoids, a pesticide known to be harmful to bees. The European Food Safety Authority has reached this conclusion after an analysis of more than 1,500 studies suggesting that neonicotinoids are harmful to bees even when they are not sprayed on the crops that feed on animals.

At the time, Nigel Raine, a professor at the Canadian University of Guelph, specializing in pollinator conservation, said: Newsweek: "More and more, there is evidence that when bees are exposed, [the pesticide] may affect their normal behavior, learning and memory, including their ability to choose flowers, their pollination efficiency and their ability to reproduce.