Bees That Fly Together Die Together

​Like that bout of mono that mysteriously infected everybody on your residence floor freshman year, wild bumblebees and farmed honeybees that live close to one another wind up sharing a lot of the same viruses, a ne​w study shows.

Bee populations across the US are diminishing, which is impacting the pollination of food and natural plant life. This research adds to the mounting evidence that the health of the two groups of pollinators are closely linked and highlights the fact that, in the search for a solution to dropping bee numbers, there is still so much we don't know about our buzzing buddies.

A paper published today in the Journal of Animal Ecology showed that viruses found in managed bees were widespread in wild bees that lived close by. Researchers collected free flying bees from 26 different locations across Great Britain and screened them for viruses common in honeybees. They found that when a virus were prevalent in one species, it was also widespread in the other.

More than 20 percent of the bumblebees collected had at least one of the five most common viruses found in the neighboring farmed bee colonies, the study found. And the total impact of any single virus could possibly be even higher, the authors noted, as very sick bees probably wouldn't be out flying around.

Since the 1940s, the number of managed honeybees in the US has dropped from 5 million to 2.5 million, according to the Department of Agricu​lture. They've been decreasing dramatically due to a combination of changes in habitat, pesticides, and diseases like deformed wing disorder and colony collapse disorder. While honeybees aren't native to North America, they've become an integral part of our agricultural pollination; the USDA estimates "one mouthful in three in our diet directly or indirectly benefits from honeybee pollination."

Meanwhile, their wild brethren also play an important role in pollinating both crops and natural plants. In fact, research sh​ows bumblebees are even more efficient pollinators than honeybees, though honeybees are easier to manage. It's long been suspected that the health of one group ripples out to the other, but there has been little research to confirm this suspicion.

Even the authors of the study published today acknowledged there is so much they still don't understand. For one, they couldn't definitively determine which way the viruses were spreading: Were wild bees getting sick and infecting the managed bees, or vice versa? Or is another insect infecting the bee groups independently? There's evidence for all three possibilities.

"With respect to wild bees, and bumblebees in particular, virtually nothing is known of the epidemiology of these RNA viruses," the paper reads, calling for more research to answer the lingering questions, like how the viruses are even spreading between the groups. "Potential transmission routes include direct contact between bees or, more likely, via indirect interactions such as through shared use of floral resources."

The impact of these viruses is also not well documented, but the researchers suggested that, left unchecked, the viruses could cause significant damage to wild and managed bee populations. The paper states that when you combine widespread viruses with the other issues impacting bee populations, like habitat change and pesticides, the pressure from pervasive diseases "could have general and profound impact on the long-term health of bee populations."

But all hope is not yet lost. Recent findings have sho​wn bees that ingest certain nectar chemicals are better at fighting off parasites, so there could be a natural solution to support our sick bee populations. We just need to get moving on more research to pinpoint what exactly is going on before it's too late.