Asian honeybees use poop as ‘tool’ to repel murderous giant hornets

A forager applies a fecal spot to the entrance of its hive in Vietnam. Heather Mattila et. al via PLoS One

If you want to kill the Asian honeybee, you’re going to have to put up with a lot of poop.

New research shows that Asian honeybees have learned to use animal feces as a deterrent against giant hornets in a never-before-seen strategy to prevent the invaders from breaching their nests and slaughtering everything inside.

It’s said to be the first documented case of bees using a tool in nature — if you consider stool a tool.

Scientists noticed the (s)crappy new combat tactic among bees in Vietnam, according to a study published Wednesday in the journal PLoS One.

The Asian honeybees, known as Apis cerana, collected animal feces and smeared it around their nest entrances to repel a giant hornet known as Vespa soror, according to the study.

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Six Vespa soror giant hornets attack the entrance of a bee colony. Heather Mattila et. al via PLoS One

V. soror is approximately one centimetre smaller than the infamous Asian giant hornet, or “murder hornet,” that is native to eastern Asia and now threatens North America. However, both species are known to storm honeybee colonies by force, decapitating the adults in droves before snatching the young and leaving the nest in ruins.

Asian bees have been facing the threat of killer hornets for a long time, and their poop defence is just one of many tactics they use to repel the invaders. This tactic is special because it’s the first recorded evidence of bees using a tool for “collective defence.”

Click to play video: 'Scientists analyze first Asian Giant Hornet nest found in the U.S.'
Scientists analyze first Asian Giant Hornet nest found in the U.S.

Researchers became suspicious when they spotted bees buzzing around buffalo, pig and chicken manure on farms in Vietnam, according to Dr. Heather Matilla, the lead study author and a researcher at Wellesley College in Massachusetts.

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Matilla told the New York Times that her “eureka” moment came when she spotted a bee trying to fly away with a piece of chicken poop.

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“I remember running back to the apiary screaming: ‘It’s true! It’s finally true!'” she told the Times.

Matilla and her team set up cameras around the local bees’ nests and recorded their behaviour for many hours. The videos proved that the bees were deliberately gathering the poop to repel the hornets.

Click to play video: 'Honeybee colonies face uncertain future'
Honeybee colonies face uncertain future

Researchers say the bees will collect animal feces after an encounter with a hornet scout, or after smelling the chemical the hornets use to mark a nest for invasion. Bees gather whatever feces they can find, then dot it around the entrances to their nest.

The hornets stay away once they see the poop on the bees’ doorstep, perhaps because they don’t want to eat where others have pooped.

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Scientists monitored dozens of bee colonies in Vietnam for their study, and found that the Asian bees were the only breed to collect feces. They also noticed that the Asian bees were less likely to suffer an attack from giant hornets, and that the bees would step up their feces collection after a close call with predators.

More research is needed to figure out why the tactic is so effective, according to Gard Otis, a professor at the University of Guelph in Ontario.

“Dung collection is a behaviour never previously reported for honey bees, and no one had studied the phenomenon,” Otis said in a statement.

They say the dung matches the definition of a tool because the bees are taking something from their environment, changing its shape, holding it with their mandibles and placing it in a specific orientation. They also acknowledge that some would argue that definition of a tool.

Asian honeybees have developed other tactics for fighting giant hornets. In some cases they will swarm over an invader and vibrate their bodies rapidly, heating up the enemy until they essentially cook it to death.

The Asian bees have developed these tactics because of the “strong selective pressure” posed by giant hornets, the study authors say.

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That hasn’t been the case for honeybees in North America, where the Asian giant hornet has started to gain a foothold along the West Coast. Experts fear the so-called “murder hornets” will tear through North America’s honeybees because they simply don’t know how to defend themselves.

“They haven’t had the opportunity to evolve defences,” Matilla said. “It’s like going into a war cold.”

That all begs a larger question for North American beekeepers: How do you train a colony to fight?

Or to put it more bluntly: How do you train bees to fight murder with poop?

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