A new study found a definitive link between weed killers and the death of bees worldwide. Researchers at the University of Texas in Austin looked at potential causes of bee deaths, a phenomenon that has been extensively written about in recent years, and discovered that the active ingredient in Roundup could be the culprit. Glyphosate, according to the study, can disrupt a bee’s gut bacteria and make it more susceptible to contracting pathogens that can eventually lead to its death. “We need better guidelines for glyphosate use, especially regarding bee exposure, because right now the guidelines assume bees are not harmed by the herbicide,” graduate student Erick Motta, who co-led the bee study, told Phys.org. “Our study shows that’s not true.” Bee deaths have been reported on over the last several years as scientists tried to determine what is causing massive die-offs in hives. Experts believe the chemicals in pesticides and herbicides are the likely culprits. The Obama White House even said in 2015 that tighter restrictions on pesticides might be necessary to save honeybees, which pollinate plants and produce honey.