A novel study of honey bee genetic diversity co-authored by an Indiana University biologist has for the first time found that greater diversity in worker bees leads to colonies with fewer pathogens and more abundant helpful bacteria like probiotic species.
“We don’t yet know what’s causing colony collapse disorder, but colonies that succumb to it suffer from a broad range of problems,” Newton said of a phenomenon that the U.S. Department of Agriculture says has taken about 34 percent of the overall U.S. honey bee population each year since 2007. “What we observed in our work was that there was less likelihood of potentially pathogenic bacteria showing up in genetically diverse honey bee colonies compared to genetically uniform colonies.”
The team was able to sample and then classify over 70,500 genetic sequences for bacterial genera from 10 genetically uniform colonies and 12 genetically diverse colonies by analyzing a specific molecule found in RNA — a first for examining honey bees and their symbiotic microbes. Their study is the largest of its kind — the single-largest analysis of newly identified active microbes ever to be identified in honey bees. In addition, they revealed that those microbes were more diverse in genetically diverse colonies (1,105 unique bacterial species) compared to genetically uniform colonies (781 species).
“What we found was that genetically diverse colonies have a more diverse, healthful, active bacterial community — a greater number and diversity of bacterial sequences affiliated with beneficial genera were found in genetically diverse colonies,” Newton said. “Conversely, genetically uniform colonies had a higher activity of potential plant and animal pathogens in their digestive tract — 127 percent higher than workers from genetically diverse colonies.”
Newton’s co-author, Heather Mattila, has been investigating the benefits of genetic diversity for honey bees for years and was thrilled to have Newton’s microbial expertise incorporated into the project.
“This is an exciting result because it gives us insight into how individual bees and their symbionts can enhance the overall health of a colony when it is genetically diverse,” Mattila said.