One study assumes that the active ingredient in Roundup could be responsible for the decline of bee populations

Glyphosate is an active ingredient in Roundup herbicide and one of the most used herbicides in the world. A new study implies that glyphosate could contribute to the death of bees around the world by making bees more vulnerable to infection.

While previous research has shown that neonicotinoids and other pesticides can be harmful to bees, glyphosate is a herbicide that targets only bacteria and plants. Although bees, which play a critical role in the pollination of nearly three-quarters of food crops, are thought to be undamaged by a herbicide, the study suggests that glyphosate could harm the microbiota of bees. Since glyphosate is used worldwide in high concentrations, researchers believe it could contribute to the decline in honeybee populations worldwide, as well as reduce the viable habitat of honey bees.

Test levels of exposure to bees

Erick Motta, of the University of Texas and author of the article, explains that bees need the microbiota in their bowels to defend themselves against harmful pathogens. Without these microbiotics, pathogens can kill them. Motta says that the study found that the dominant intestinal bacteria in bees are diminished in bees that have been exposed to glyphosate levels documented in the environment. Motta and colleagues found that worker bees that had been exposed to glyphosate were more likely to die when exposed to an ubiquitous bacterium.

The study by Motta and his colleagues was published in the Proceedings of the National Academy of Sciences and states that glyphosate "alters the intestinal community of bees and increases their susceptibility to infections by opportunistic pathogens." Not only were bees exposed to glyphosate becoming more sensitive to pathogens, but researchers found that it hindered the ability of bees to develop a normal intestinal biome in the first place. However, other studies in China have shown that honey bee larvae grow much more slowly and are more likely to die after exposure to glyphosate. It is also thought that exposure to glyphosate degrades the cognitive abilities of adult bees, which complicates their navigation and their return to the hive after release.

The researchers collected hundreds of adult worker bees and then gave them doses of glyphosate to mimic the concentrations of glyphosate present in the environment. The researchers treated the bees with either a large dose (10 mg / L of glyphosate [G-10]), a small dose (5 mg / L of glyphosate [G-5]), or a sterile sucrose syrup as a control. Glyphosate concentrations in the environment are estimated to be between 1.4 and 7.6 mg / L because bees can feed around weeds and flowers.

The bees were then returned to their original hives and marked with a point of paint on their thorax so they could be distinguished from other bees in the hive. Less than 20% of bees reintroduced into the hive (a sample of 45) have been recovered by scientists and they believe that recovered bees may not reflect the total population of bees affected by the effect of glyphosate on treated bees.

Too much use of herbicides?

The herbicidal effects of glyphosate can destroy the plants that bees depend on to survive, according to Matt Sharlow of Buglife, an environmental protection group. So even though the herbicide is not very toxic to bees themselves, the study suggests that the use of pesticides and herbicides can have unintended consequences, including habitat destruction.

Dave Goulson, a professor at the University of Essex, says that glyphosate should be added to the list of threats that bee populations face and that widespread application of pesticides and pesticides Herbicides can harm insects in an unexpected way. Other studies on glyphosate have shown that it has a deleterious effect on intestinal bacteria in the rat and Goulson claims that intestinal bacteria are an essential ingredient for being healthy for a wide variety of organisms such as humans and the bees. Goulson goes on to say that the finding that the bacteria found in the gut of bees appears to be sensitive to herbicides and pesticides as glyphosate is "worrisome".

With Motta, researchers Moran and Raymann fear that glyphosate contributes to the imbalance of colonies, a phenomenon where most worker bees of a colony disappear and the colony does not survive. Motta explains the concern:

We need better guidelines for the use of glyphosate, especially with regard to bee exposure, because at the moment, the guidelines assume that the herbicide does not harm bees. Our study shows that this is not true.

Reviews of the study

However, while Motta and his colleagues fear that glyphosate may be contributing to bee deaths and colossal collapse disorder, others warned against a too quick charge on glyphosate. Skeptics about the results of the study point out that the level of glyphosate used in the study may have been much higher than what a bee could exhibit in the environment.

Oliver Jones, a chemist at RMIT University in Melbourne, says the doses used are probably too high and do not adequately reflect the amount of glyphosate the bee is likely to encounter in the environment. Therefore, according to Jones, the results of the study prove that glyphosate could harm the bowels of bees, "this is not the case in the environment". Other culprits, such as global warming, mites contributing to colony collapse disorder.

Concerns were also expressed about the scope of the study. The size of the study sample was 45 or 15 bees from each of the three test groups. Criticisms have been made that the size of the study is too small and larger studies have shown that glyphosate at gatherings was largely safe for bees. Monsanto says that no large-scale study has shown that glyphosate is linked to bee deaths and claims that more than four decades of solid research have shown that glyphosate "poses no unreasonable risk to Man, animals and the environment in general.

Human impact

With respect to the impact of glyphosate on humans, epidemiological studies of glyphosate exposure suggest weak links between glyphosate and non-Hodgkin's lymphoma types. The bioaccumulation of glyphosate remains however a concern for many scientists, including toxicologist Felix Carvalho of Porutgal's Prot University, who says that the increasing use of glyphosate in herbicides means that people are exposed to glyphosate at increasing doses potentially deleterious.

However, a 2016 analysis of more than 90,000 workers exposed to glyphosate on farms for more than two decades found no statistically significant association between glyphosate and non-Hodgkin's lymphoma. In addition, a systematic review of cancer and glyphosate conducted in 2012 found that there was "no positive association pattern" between cancer and major cases and exposure to cancer. glyphosate. Although glyphosate can be dangerous at a certain level of concentration, so are all other chemicals, and the questions are about the dosage to which people are exposed. In this regard, scientists and doctors like Steven Novella, clinical neurologist at the Yale University School of Medicine, fear that the fight against glyphosate is counterproductive and that its replacement is even worse for health. human and environmental. .

In the end, the glyphosate safety debate about bees is raging, and while the University of Texas study is interesting, more research is needed to determine if glyphosate poses a significant risk to humans. the bees.