Bacteria in flowers may boost honeybees’ healthy gut microbes

Fructobacillus may be critical to larvae gaining ability to digest insects’ diet, study suggests


BUSY BEE   A honeybee may collect beneficial bacteria while it’s harvesting pollen and nectar from flowers.

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Honeybees were into probiotics way before they were cool, a new study suggests.

The hipster insects serve up beneficial bacteria that may help baby bees develop a healthy blend of gut microbes, researchers report online August 7 in Applied and Environmental Microbiology. Without those thriving gut communities, the critical pollinators may have trouble digesting their plant-based food.

It’s a lot like getting a dollop of probiotic yogurt, says study coauthor Irene Newton, a microbiologist at Indiana University Bloomington. The supportive bacteria, Fructobacillus, may help bee microbes settle snugly in young bee guts. And, just like in humans, a dose of antibiotics — at times used to ward off hive diseases — might disrupt the process, she warns.

Newton and colleagues discovered the charitable bacteria while surveying the microbes in three hives. Researchers knew that the bee’s microbiome builds in steps, but they weren’t sure what the steps were.

Newton’s team identified microbial mixes in nurse bees, bee larvae, nectar, pollen and the hexagonal bee nurseries in the hive. Then the group compared the mixes and mapped out how microbes spread around the hive and to its occupants.

Fructobacillus, found in flowers, stood out as being present throughout the hive and in bee nurseries, Newton says. The bacteria may enter the hive with returning forager bees and move around it by bee-to-bee contact or when the bees share food.

When growing bee gut microbes in the lab, the researchers found that the tummy-dwellers grew better with Fructobacillus than without it. Though it’s unknown if this also happens inside bees, Newton thinks that the bacteria could give the gut microbes a foothold in the young bees’ innards by producing helpful metabolic compounds.

“It is a good first step” in understanding how microbes get established, says evolutionary biologist Nancy Moran of the University of Texas at Austin. But, she says, the study should be repeated with more bees and hives before the inference about the bacteria’s role is conclusive.

Newton’s team also found that tetracycline, a drug sometimes used to prevent bee diseases, could kill Fructobacillus. (Microbes in the bee microbiome are often resistant to antibiotics.) The study, though preliminary, suggests that doses of antibiotics could disrupt honeybees’ microbe-building process, Newton cautions.

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