Newswise – TORONTO, June 17, 2022 – The local environment plays a key role in the health and diversity of the intestinal microbiome of wild bees that could help detect invisible stressors and early indicators of potential threats, say scientists York University in a new study.
Piloting a new frontier of metagenomics, the researchers sequenced entire genomes of three species of wood bees, a type of wild bee, in North America, Asia and Australia. This analysis allowed them to obtain information about the bee’s intestinal microbiome (bacteria and fungi), diet and viral load, as well as its environmental DNA.
Unlike social bees (such as honey bees and bumblebees), researchers found that solitary bees get their microbiome, which is important for health, from their environment where they are forged to eat, rather than inherit it from their nest mates. Wood bees are buried in the stems of woody plants to lay eggs instead of beehives.
“This can make them better bioindicators, as they are much more sensitive to their environment,” says Sandra Rehan, an associate professor in the Faculty of Science. , published today in the journal Communications Biology.
In Australia, local populations had very distinctive metagenomes and microbiomes; so much so that machine learning tools were able to reliably predict from which population each bee was extracted.
The research team also discovered crop pathogens in the microbiomes of wood bees that were previously only found in honey bees.
“These pathogens are not necessarily harmful to bees, but these wild bees could be vectors of diseases that could have negative effects on agriculture,” says Rehan. Finding out how these pathogens are spreading to wild bees is important, as bees contribute to ecological and agricultural health worldwide, in addition to more than $ 200 billion in annual agricultural services.
Establishing a baseline of what a healthy microbiome looks like in wild bees allows scientists to compare species between continents and populations, and find out how diseases and harmful microbiota are introduced and transmitted.
“We can really dissect bee health in a very systematic way by looking at population genetics and loads of parasitic pathogens, healthy microbiomes, and deviations,” says Rehan, whose postdoctoral fellow Wyatt Shell direct the study. “The long-term goal is to really be able to use these tools to be able to detect even the first signs of stress and habitats that need restoration or conservation. To develop it almost as a diagnostic tool for bee health.”
Researchers believe they have captured the central microbiome of wood bees for the first time. They found beneficial bacteria in all three species of wood bees that helped with metabolic and genetic functions. They also detected species of Lactobacillus, which is a group of beneficial bacteria essential, essential for good intestinal health and found in most bee lineages. Lactobacilli can protect against prevalent fungal pathogens, boost the immune system, and facilitate nutrient uptake.
However, an article recently published in the journal Environmental DNA by Rehan and his graduate student Phuong Nguyen, Microbioma of the development of the small carpenter bee, Ceratina calcarata, which studied the microbiome of adult carpenter and breeding bees in cities, found that they did not have Lactobacillus.
“That raises red flags,” Rehan says. “We continue with these studies to analyze more nuanced urban and rural comparisons and long-term data to truly understand these environmental stressors. Every time we characterize a microbiome and see deviations from what we know is normal, it can give us an indication of a population. or endangered species “.
Overall, the results show that metagenomic methods could provide important information about the ecology and health of wild bees in the future.
“We have been piloting this research approach in some species, but we intend to study dozens of wild bee species and broader comparisons will be made. These two studies are really laying the groundwork,” he says. “The long-term goal is to really be able to use these tools to detect early signs of stress in wild bees and therefore identify habitats that need restoration or preservation. We are excited to be building the tools for a new era. of research and conservation of wild bees “.
The work was funded by NSERC Discovery Grants, Weston Family Foundation Microbiome Initiative funds and the NSERC EWR Steacie Memorial Fellowship to Rehan.
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