UT researchers found two insecticides approved by the United States Environmental Protection Agency that have harmful and lethal effects on bees and other beneficial insects.
The new insecticides Sivanto and Transform WG have significant harmful impacts on beneficial insects such as wasps, lacewings and beetles, according to a research article published in the biological sciences journal Proceedings of the Royal Society B. Harry Siviter, integrative biology postdoctoral fellow, said the research included an analysis of the available scientific literature about the effects of these insecticides.
“What we've found over the last couple of decades really is even though insecticides might not be lethal to bees … , they can have some painful effects,” Siviter said. “So, influencing reproductive output behavior, colony level fitness (and) even silly things like flight.”
The analysis focuses on the sublethal effects, or harmful effects that are not lethal, because EPA regulations for insecticides focus on toxicity, which examines how much of a chemical is required to kill an insect or 50% of its population, Siviter said.
“My general frustration is it's this continuing cycle where insecticides are continually released without us knowing the potential sublethal effects,” Siviter said. “This seems to be a never-ending cycle, and you can actually trace it all the way back to the end of the Second World War.”
Felicity Muth, an integrative biology assistant professor, said the regulatory process must take into account the sublethal effects. The insecticides analyzed replace a class of pesticides called neonicotinoids, she said.
Neonicotinoids are the most commonly used insecticides in the world, according to the research. Muth said neonicotinoids were approved because they were found to not have lethal effects, and the sublethal effects were overlooked. Neonicotinoids are “used across the country” in America but are heavily restricted in both Canada and the European Union, according to an op-ed Siviter wrote for The Hill.
“You can ban one pesticide … group like neonicotinoids,” Muth said. “But if they then just get replaced by something that's just as bad, then it shows that the system doesn't work and that we need to have a new regulatory system.”
Muth said most insecticide research evaluates effects on honeybees, which are one of 4,000 species of bees in North America. She said they are all important for our ecosystems, and they will all respond differently to pesticides.
The results of the study show that bans on neonicotinoids can protect beneficial insects only if the regulatory process is changed as well. According to the research, if the regulatory process is not modified, beneficial insects and ecosystem health will continue to suffer.
Muth said she hopes the regulatory process adapts to protect beneficial insects. Around 35% of global food production depends on pollinators. Beneficial insects help control crop pests, so beneficial insect declines can threaten our food supply, according to the study.
“The science isn't ambiguous, and it's up to lawmakers to decide what they want to do,” Muth said. “They don't always listen to scientists, but I think the more evidence that there is for something, the more likely it is that lawmakers will listen.”