One of the most widely used weedkillers in the United States might be indirectly causing the rapid decline of honeybee population.
Researchers from the University of Texas found that glyphosate, an active ingredient of the popular weedkiller brand Roundup, might be contributing to the widespread deaths of honeybees and native bees around the world.
The study was published in the journal Proceedings of the National Academy of Sciences.
Deadly Effects Of Glyphosate
Glyphosate is an effective weedkiller because it interferes with an enzyme found in plants, but has long been assumed to be nontoxic to humans and animals. However, researchers from the University of Texas exposed honeybees to glyphosate and found that the herbicide has significantly reduced healthy gut microbiota.
Snodgrassella alvi, a species of bacteria that process food and defend the bee against pathogen, was less abundant three days after exposure to glyphosate. Bees with impaired gut microbiomes are more likely to die when exposed to Serratia marcescens, an opportunistic pathogen known to kill bees around the world.
"Studies in humans, bees and other animals have shown that the gut microbiome is a stable community that resists infection by opportunistic invaders," explained Nancy Moran, a professor at University of Texas and one of the authors of the study. "So if you disrupt the normal, stable community, you are more susceptible to this invasion of pathogens."
Native bumblebees also have the same species of gut bacteria as honeybees. Although not tested, Moran added that the herbicide might have the same effect on bumblebee populations.
The use of glyphosate in common households is not the sole reason why bees are dying at an alarming rate. However, the authors hope that their findings would guide farmers, landscapers, and homeowners into choosing a more environmentally friendly weedkiller.
"We need better guidelines for glyphosate use, especially regarding bee exposure, because right now the guidelines assume bees are not harmed by the herbicide," stated Erick Motta, a graduate student and a coauthor of the study.
The Bees Are Dying
Previous studies have revealed that bees are dying at an alarming rate due to climate change, habitat loss, the emergence of foreign pests, and widespread use of pesticides. Between April 2015 and April 2016, beekeepers in the United States reported losing 40 percent of their colonies. In the United Kingdom, beekeepers lost almost 17 percent of their colonies. The same trend is being experienced around the world.
The importance of bees to the world cannot be emphasized enough. Most plants rely on bees to naturally pollinate and produce flowers or foods.