Interactions between bee gut microbiotas and pesticides

The researchers present the results of their review in the article "Pesticide-induced disturbances of bee gut microbiotas", published in FEMS Microbiology Reviews.

It is well known that social bees, such as bumble bees, honey bees, and stingless bees, are very important pollinators for agricultural and native plant communities.

"These bees have highly specialized gut microbiotas that provide benefits to the bee hosts, such as protection from pathogens and parasites," explained first author Michelle Hotchkiss, a PhD candidate in the Faculty of Science at the University of Ottawa. "If pesticides disturb these microbial communities, then there's a possibility those benefits will be lost and bees will experience a decline in health and performance, which may impact bee colony growth and pollination services."

Hotchkiss and her co-authors, Drs. Jessica Forrest and Alexandre Poulain, worked the computers for more than a year and a half, and searched literature databases to find articles where researchers exposed social bees to pesticides and then tracked changes in their gut microbiotas. "The earliest studies we found were published in the 1970s and the most recent ones in 2020," said Hotchkiss.

"We summarized what methods were used to collect data, including which bee hosts and pesticides were examined. To summarize how the abundances of core microbes changed after pesticide exposure, we looked at studies that used molecular methods to characterize changes in microbial abundances," she added.

"Importantly, we determined which microbes are most commonly affected by pesticide exposure and how they are affected. For example, does abundance increase or decrease after exposure? To what extent?" said Hotchkiss.

The researchers also found that, currently, the scientific community has a limited understanding of how these common changes in microbial abundance affect bee hosts, which is a major gap in this field.

This review made Hotchkiss and her colleagues realize that more research on this topic is required.

"Social bees have gut microbiotas that contribute to their health, just like we (humans) do. Further research on the interactions between pesticides, bee gut microbiotas, and bee hosts will help us better understand how pesticides affect bee health and performance."