Honeybees, principal pollinators in agriculture and natural environments, have suffered from colony declines in recent years. The bees’ pollen-rich diet and the bacteria living in their gut are known contributors to their health, and understanding the functions of bees’ various gut bacteria could have implications for colony health as a whole.
A new PLOS Biology study investigated the function of specialized bacteria that help digest components of bees’ floral pollen diet and produce molecules that likely promote bee health.
“We took advantage of the key characteristics of the bee gut microbiota: its simplicity,” says Philipp Engel, the corresponding author of the study. “Contrary to human gut microbiota, the bee gut is composed of only a few bacterial species. This makes analyzing each member separately and determining its contribution to the overall metabolite changes in the gut feasible.”
The researchers measured the repertoire of simple chemical compounds – the so-called “metabolome” – in bee guts. They then compared the gut metabolomes of bees seeded with different species of known bee gut bacteria individually and in combination. By this method, the team identified what each bacterial species contributes to bee digestion and the various strategies bacteria deploy to coexist in the animal gut.
Of particular note, they identified one species of the genus Lactobacillus that digests specific plant compounds called flavonoids – abundant in pollen and recently linked to the health of mice and humans through their breakdown by the mammals’ gut microbes. Another bee gut bacterial species, Bifidobacterium asteroides, triggered the production of bee hormones that modulate the immune system and behavior of its host.
“We have identified many exciting metabolic functions of bee gut bacteria,” Engel concludes. “The next step is to understand how these functions impact a colony’s health so that one day we can apply our findings in apiaries.”
Reference: Kešnerová L, Mars RAT, Ellegaard KM, Troilo M, Sauer U, Engel P (2017) Disentangling metabolic functions of bacteria in the honey bee gut. PLoS Biol 15(12): e2003467. https://doi.org/10.1371/journal.pbio.2003467
Image Credit: Bob Peterson, Flickr