How Does A Honeybee Colony Think?


As any kid with a mason jar can tell you, the honeybee isn’t the smartest animal on the planet. But oddly enough, a honeybee colony is actually pretty intelligent. Without the understanding of any single bee, the colony is constantly weighing decisions and making choices—like sending workers to the best place to collect food, or efficiently allocating jobs. You have to wonder, how does the honeybee group make decisions when the individuals can’t?

Although you might think the queen bee plays some role in this, she actually has no say in the decision-making. Instead, a honeybee colony "thinks" by combining and evaluating information from all the bees in a colony-wide discussion. In action, here’s how it works.

House Hunting

The most important decision a honeybee colony will ever make is choosing the best place to build a new hive—which a colony does when their old hive is destroyed, or when a new queen is born. If the honeybees pick a spot that’s too small, they might not be able to store enough honey to make it through the winter. And if they find somewhere too exposed, or with too big of an opening, predators could get in. “But over and over again, honeybees have shown that they almost always make the best decision,” says Dr. Gro Amdam, an entomologist at Arizona State University.

Amdam says that the temporarily-homeless honeybees will huddle together into a writhing pile—which can be up to several thousand bees thick—as they make their choice. While the rest of the colony waits, a few hundred bees will self-select as scouts, and scour the countryside for options. When a scout comes across something appealing, “like a cavity in an old tree,” says Amdam, “it will investigate how ‘good’ the site is by crawling around and evaluating things like the size of the entryway and the volume of the cavity.”

The scout then takes the information on the location and quality of the potential nesting site back to the swarm pile. If the scout was pretty impressed, “it will lobby for that site,” says Amdam, by dancing on top of the mound of living bees. The wiggles and steps of the scout’s dance convey the exact location of the site; how vigorously the scout dances indicates how good it thought the site was.

“A bee that was really impressed will be really geared up, and will dance for a very long time,” says Amdam, “and that enthusiastic dance will recruit more bees to come check out the site.” And after a newly recruited bee returns from evaluating the nesting site for itself, it also starts dancing as enthusiastically as it deems appropriate.

At any one time, there could be a dozen or more nesting sites that different groups of bees are vigorously dancing for. But because the bees dancing for the best sites are doing so for the longest time, explains Amdam, they have a better probability of getting others to pay attention. This forms a positive feedback loop, and slowly the better nesting options start to beat out the worse ones, continually gaining more and more bees to lobby for them.

It’s important to note that, even though the colony is slowly whittling away its options, at no point is any one bee is ever consciously comparing any two potential nesting sites. Nonetheless, the sites that start to dominate the swarm’s dance-discussion will almost invariably be the best choices, just as if some overseer had weighed them all against each other. And when a single site finally beats out all the rest—convincing a significant majority of the scout population to dance for it—the entire swarm will break from the dance-conversation, and will take off en masse to fly to their new housing choice.

Honeybees and Neurons

“And that’s exactly is what a honeybee colony’s thinking looks like,” says Keith Delaplane, another entomologist at the University of Georgia. "It looks like individual bees dancing, and other bees paying attention to those dances and slowly reinforcing or discouraging them through sheer numbers until a critical mass is reached.” Delaplane explains that this same type of behavior is also seen when the colony forages for food or water, or needs to come together to make other important decisions.

Interestingly enough, honeybee colonies aren’t the only place that we see this type of emergent behavior. “In our own brains, neurons are doing things very much like in the honeybee colony,” says Delaplane. Groups of discrete organisms or components (in the case of the brain, the neurons) combine together using set rules and feedback loops of information to accomplish tasks that the individuals couldn’t.

In some ways, the intelligence that arises from a colony of honeybees, “is like a window for us to peer inside our own minds and see how some of these processes work,” says Delaplane.

Oakley Originals, Flickr Creative Commons // CC BY 2.0
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]

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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