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Honeybees Trained to Sniff Out Drugs

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Researchers in Germany have trained honeybees to sniff out drugs, according to a new study, suggesting the insects could someday be good alternatives to police dogs.

After exposing the bees to the scent of heroin accompanied by small electric shocks, the researchers found the insects quickly associated the smell with punishment and exhibited learned “avoidance” behavior, fleeing the source of the odor. They suggest honeybees could one day identify illegal substances in luggage and other contained spaces.

Why do we need drug-detecting bees in the first place? The problem is twofold, says Matthias Schott, coauthor of the study and a biologist, entomologist, and chemical ecologist at Giessen University. 

Training police K-9 units is expensive. According to one cost analysis, the average successful canine police program costs more than $55,000. (That analysis is from 2004, so the cost is likely higher now.) The dog and the handler training alone cost around $14,000, and it can take several years for a dog to be ready to hit the streets. “Dogs also, like humans, need time to rest and cannot concentrate for a long time,” Schott tells mental_floss. “You cannot search a whole airplane with a dog. It’s too much for one dog.”

Secondly, many existing drug-sniffing dogs have been trained to sniff out marijuana. But as marijuana is increasingly legalized, we need dogs to focus on drugs that remain illegal. That's a problem because “it’s not really possible to retrain a dog,” Schott says. “There is a need for freshly trained dogs at the moment, and it takes a long time.”

The ideal alternative drug hunter has good stamina, quick learning skills, and a fantastic sense of smell—and honeybees have all three. That's why Schott put a fake flower on a windowsill in his lab: to lure honeybees for testing. Drawn by an artificial sugar solution, they came—and were trapped. Schott used about 60 in his experiments.

His next step was to find some drugs. Luckily, the Forensic Science Institute of the German state of Hesse and the Police Laboratory for Criminal Technology allowed his team to work with seized heroin, cocaine, amphetamine, and cannabis—but under strict surveillance. “We had to do the experiments at the lab of the police,” Schott says. “We were watched all the time when we did the experiments. It was quite strange.” 

Since honeybees sense smell with their antennae, translating odors into electrical signals, their sensitivity to drugs can be measured by connecting the antennae to electrodes. In the lab, the bees had the strongest antennal response to heroin and cocaine. 

Using negative conditioning (a.k.a. punishment), Schott then trained the bees to sniff out and respond to the smell of heroin. He placed them in a tiny closed chamber about 1 centimeter high and 15 centimeters long that was lined with a metal grid. Because the chamber was so small, the insects were forced to be in contact with the metal at all times. At each end of the chamber were openings where odors were introduced. If the bee was positioned on the left side of the chamber, the odor would come from the left side, and vice versa.

Schott trained the bees to flee from the smell of heroin by introducing a small electric shock each time the drug was pumped into the chamber. As soon as the bee crossed over to the other side of the chamber, fleeing from the scent, the shock stopped. “She will get a shock, but really quickly she learns it and she will run away from it and will not receive more shocks,” Schott says.

After five minutes of conditioning with the heroin odor and a control odor (cis-3-hexenol, “an intense grassy-green odor of freshly cut green grass and leaves”), the bees could take a quick break before being tested again, this time without any electric shock punishment. If the bee still fled the smell of the drug even when there was no electric shock, the learning was complete.

“We observed a significant avoidance reaction when honeybees were presented with the heroin scent after training with heroin as a conditioned stimulus,” the authors write.

The entire process took less than 15 minutes, and then the bees were set free. 

But honeybees are pollinators. They already have a very important job—and they're in trouble. Do they really need to be hunting down drug traffickers? Schott says his study uses a very small sample. “I’m using 60 bees of a beehive, and a beehive has 30,000 bees in the summer, so it doesn’t do them a lot of harm,” he says. Plus, once the bees are trained, they can be used to sniff out illegal substances and then immediately released, none for the worse.

Schott also studies the bee decline and hopes these kinds of studies help raise awareness about their plight.

It’s not likely you’ll see drug-sniffing bees at border control just yet. The current applications are quite limited, since the bees would need to be in small, yet-to-be designed containers: “a suitable device would contain 40 honeybees in behavioral monitoring chambers into which the test scent could be drawn, and avoidance behavior would trigger an ‘alarm’ equivalent to the analogous signal given by sniffer dogs,” according to the study. 

Schott clarifies, “I would put them in a cupboard where you have air sucked in from luggage or something, and the bees are monitored. When they start to flee from that odor, then you know" heroin is present, he says. 

Next he hopes to compare the bees’ newfound narcotic-hunting skills to those of police dogs. “Can the bees perceive what the dog can perceive?” Schott asks. “They don’t have to be better than the dogs. It’s fine if they are just as good as the dogs. I think that would be quite cool.” 

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Oakley Originals, Flickr Creative Commons // CC BY 2.0
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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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