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Jody Morris, Flickr // CC BY-SA 2.0
Jody Morris, Flickr // CC BY-SA 2.0

How Do Honeybees Survive the Winter?

Jody Morris, Flickr // CC BY-SA 2.0
Jody Morris, Flickr // CC BY-SA 2.0

As hard as bees toil during their peak seasons—pollinating and generally making sure humanity doesn’t come crashing down in a Biblical-level disaster—you’d think the colder months would bring some kind of hibernation or rest, even if it means snowy death.

For bumblebees, that’s generally true. Unable to tolerate lower temperatures, mass bee graves in northern regions are not an uncommon sight, with only the queen retiring to a warm crevice. But for the honeybee, winter is a time to buckle down and labor even harder in an all-out effort to extend their life span.

Their secret: fly without actually moving.

A single honeybee will typically die of exposure once temperatures plummet to 28 degrees. In order to survive, a colony will need to (literally) huddle together to create a communal furnace fueled by their body heat. That’s generated by the bees contracting muscles in the thorax responsible for flight. The wings remain still, but the energy created can raise a bee’s core temperature.  

Having morphed into tiny space heaters, the bees arrange themselves into a cluster not unlike a football huddle, their little bee heads touching and their abdomens (which are cooler) facing out. The outermost layer flirts with a cooler temperature of 46 degrees, chilly but survivable. They comprise the shell, or “mantle,” that protects the queen. In the core, insulated by layers of bees, the temperature can get up to a downright toasty 95 degrees.

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Bees also react to environmental changes. If things cool down further, they can contract and raise the temperature; warmer ambient weather allows them to relax and spread out a little. The mantle isn’t always stuck with the worst job, either. They can regularly burrow their way into the core to enjoy the bee equivalent of a cozy fireplace.

Typically, the bigger the cluster, the less each individual bee will have to work in order to maintain their thermostat setting, and the better the chance is for overall survival. But a huddle of any size requires energy, and their stockpile of honey might be just far enough away in the hive that breaking off from the group could mean death. The cluster will usually move in unison to reach untapped honey stores.     

Despite the ability of the honeybee to adapt to frigid temperatures, in modern times their survival often requires beekeeper intervention. Bees in particularly cold regions benefit from a layer of fiberglass insulation around the colony. Beekeepers also keep honey stores stocked to ensure the bees will have enough fuel.

Because of mites and other parasites, colony survival rates have varied over the years. In the 2013-14 winter season, beekeepers reported roughly a 25 percent loss, a slight improvement over the year prior—but enough to keep concerns raised about the continuing collapse of bee colonies.

Additional Sources:
“Wintering Management of Honey Bee Colonies.”

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Oakley Originals, Flickr Creative Commons // CC BY 2.0
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Animals
Could Imported Sperm Help Save America’s Bees?
Oakley Originals, Flickr Creative Commons // CC BY 2.0
Oakley Originals, Flickr Creative Commons // CC BY 2.0

It might be time to call in some sexual backup for male American bees. Scientists have started impregnating domestic honeybees with foreign sperm in the hopes that enlarging the gene pool will give our bees a fighting chance.

These days, the bees need all the help they can get. Colonies across the globe are disappearing and dying off, partly due to the increased use of neonicotinoid pesticides and partly from a parasite called the varroa mite. The invasive mite first landed on American shores in 1987, and it's been spreading and sickening and devouring our bees ever since.

Part of the problem, researchers say, is that the American bee gene pool has gone stagnant. We stopped importing live honeybees in 1922, which means that all the bees we've got are inbred and, therefore, all alike. They lack the genetic diversity that allows species to adapt to changing conditions or new threats. So when the mites come, they all get hit.

Many apiarists now rely on anti-mite pesticides to keep their charges safe. While these treatments may help keep the mites away, they aren't great for the bees, either—and the mites have begun to develop a resistance. But beekeepers feel like their hands are tied.

"I lost 40 percent of my colonies to varroa last fall," Matthew Shakespear of Olson's Honeybees told NPR. "I'm not taking any more chances. We've already done five treatments, compared with the two treatments we applied this time last year."

But there might be another way. Experts at the University of Washington have started to—how can we put this delicately?—manually encourage drones (male bees) in Europe and Asia to give up their sperm. All it takes is a little belly rub, and the drone, er, donates 1 microliter of fluid, or one-tenth of the amount needed to inseminate a queen bee.

"They're really accommodating," bee breeder and researcher Susan Cobey told NPR. 

It's hardly a painless procedure, but researcher Brandon Hopkins told Mental Floss it's no worse than sex in the wild. "In natural mating he uses pressure from muscles and hemolymph to evert [his genitals], (inflating it and forcing it to pop out)," Hopkins wrote in an email. "In the lab we apply pressure to the head and thorax to create similar pressure to cause the eversion. In both cases (naturally and artificially) the male dies from the process of mating."

So far, the scientists' attempts to crossbreed foreign and domestic bees have been successful. Within their test colonies, genetic diversity is up.

"This doesn't mean they are superior in performance to the other bees," Hopkins told NPR. "It means we have a better chance of finding rare and unique traits." Traits, Hopkins says, like genetic resistance to the varroa mites—a quality shared by donor bees in Italy, Slovenia, Germany, Kazakhstan, and the Republic of Georgia.

Other beekeepers are opting for a more hands-off approach, introducing imported queens to their domestic hives. Shakespear bought his from Cobey, who reared them from bees she collected in Slovenia.

"Maybe these new genetics can deal with the varroa mites naturally," Shakespear said, "rather than having to rely on chemicals. It's time to start widening our gene pool."

[h/t The Salt]

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Study Finds Pesticide Makes It Hard for Bees to Fly on Target

Scientists say a widely used pesticide can affect honeybees’ ability to fly, making it harder for foraging bees to find their way home. They published their findings in the journal Scientific Reports.

Bee populations worldwide are currently facing a mountain of threats and difficulties. Parasites, habitat loss, and even antibiotics have all been implicated in the bees’ decline, but it may be pesticide that’s doing the most damage.

Foraging honeybees (Apis mellifera) regularly take in small amounts of chemicals like thiamethoxam, a neonicotinoid pesticide that’s regularly sprayed on monoculture crops like cotton, soybeans, and corn. A little dose won’t kill the bees, and it won’t keep them from coming back to consume more the next day. Over time, that chronic exposure can mess them up.

Biologists at the University of California San Diego’s Nieh Lab wanted to know if and how thiamethoxam could affect bees’ ability to fly. They exposed honeybees to low doses of the pesticide for two days, then strapped each one into this unusual contraption—the bee version of a treadmill.

At first, the pesticide almost seemed like it was doing the bees a favor. Thiamethoxam-exposed bees initially flew much farther and faster than bees who’d never been near the chemical.

The problem is that they weren’t flying anywhere in particular. They seemed disoriented and soon wore themselves out in their mad, flailing dash to get where they wanted to go. On the treadmill, this panic-type flying didn’t do them any harm, but in the wild, these erratic, exhausting flight patterns could keep the bees from ever getting home.

To make matters worse, given a choice, the bees almost always opted to consume pesticide, and they ate more when their food had been laced with the stuff.

"The honey bee is a highly social organism, so the behavior of thousands of bees are essential for the survival of the colony," co-author James Nieh said in a statement. "We've shown that a sub-lethal dose may lead to a lethal effect on the entire colony."

Header image by Luc Viatour via Wikimedia Creative Commons // CC BY-SA 3.0

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