The Current

'Murder hornets' could spell trouble for Canada's bee populations, but offer little threat to humans: experts

In recent weeks, concerns have grown over the Asian giant hornet after colonies were discovered in Washington state. But Canadians shouldn't be too worried about so-called 'murder hornets' as they're more interested in bees than humans, experts say.

But entomologist Conrad Berube warns the Asian giant hornet's sting is like 'red hot thumbtacks' piercing skin

A closeup of an Asian Giant Hornet is seen in an undated Washington State Department of Agriculture picture obtained by Reuters on May 4, 2020. (Washington State Department of Agriculture/Reuters)

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Canadians shouldn't be too worried about so-called "murder hornets" as they're more interested in bees than humans, experts say.

"It should certainly be prefaced with the noun honeybee, because they're honeybee murder hornets," said B.C. entomologist and beekeeper Conrad Berube.

In recent weeks, worries have grown over the distressingly nicknamed insect, formally known as the Asian giant hornet, after colonies were discovered in Washington state.

The wasp, which is part of the same order of insects as bees, can grow up to five centimetres (or two inches long). It's also an apex predator, meaning that no other insects hunt or feed on them.

Entomologist Conrad Berube, far right, is pictured on Sept. 18, 2019, with an Asian giant hornet. He was sent in to destroy a nest of the so-called 'murder hornets' discovered in Nanaimo, B.C. (Submitted by Conrad Berube)

Speaking to The Current's Matt Galloway, Berube says there's little evidence that the giant hornets currently pose a significant threat to Canada.

The only known nest in this country was discovered — and destroyed — in Nanaimo, B.C., last September, however the hornets were also sighted in White Rock, B.C., in November. 

But beekeepers are raising the alarm over the potential arrival of Asian giant hornets as the insect can decimate entire honeybee colonies in short order.

According to experts, bee populations — key to pollinating everything from fruit to canola seed crops — are on the decline.

'Can kill 20,000 to 30,000 bees' in hours

The hornets employ what B.C.'s provincial apiarist Paul van Westendorp calls "big mandibles" to catch and kill their prey.

Scout bees, he explained, will leave a trail of pheromones leading to a bee hive and then recruit some of its sisters — all giant hornets are female — to create a panic in the hive.

"So the bees are coming out and they slice them and they slice them, and they can overwhelm a colony over a span of a few hours. And during this time, the panic is so much that the bees no longer defend the nest," van Westerndorp told As It Happens host Carol Off.

"The hornets can then move in to collect and raid the bee brood that they carry back to their own nest."

B.C. has small population of giant ‘murder hornets’

3 years ago
Duration 2:04
Experts in B.C. say there is a small number of Asian giant hornets, dubbed “murder hornets,” in the province and the risk to humans is low.

The giant hornets then turn the honeybees into a sort of "bee hamburger" to feed to their larvae, said Berube.

"A few dozen of the hornets can kill 20,000 to 30,000 bees in the course of a couple of hours," he added.

Sting like 'red hot thumbtacks'

Though both Berube and van Westendorp argue "murder hornets" is a bit of a misnomer, the insects were given the sinister title in Japan where they're known to kill people, the Associated Press reported.

"The problem with this character is ... it has a large volume of venom and it has a smooth stinging apparatus, so it can sting repeatedly," said van Westendorp.

"Its venom also contains an enzyme and peptide that is causing tissue necrosis — so causing the tissue to dissolve, and therefore, you have an increased danger of an infection afterwards," he said.

Berube adds that the Asian giant hornet's stinger can be up to a quarter-inch long, meaning it can penetrate beekeepers' protective gear. That's a lesson he learned when he was tasked with eradicating the nest in Nanaimo last fall.

While he warns against panic over the wasps, he admits their sting is no walk in the park.

"Having disturbed them, and having squatted down, the fabric of the two pair of pants that I was wearing was stretched tight across my legs and I got four stings," he said.

"It's like having red hot thumbtacks driven into the flesh."

The entomologist says that Canadians can help track the spread of the Asian giant hornet by following the "slap, snap, zap and wrap" method.

If you can do so safely, Berube encourages Canadians who think they've encountered the insect to kill it by slapping it with a stick, snap a photo and "zap" it in an email to the Invasive Species Council of B.C., then wrap it in plastic and freeze it "in case a sample is needed."

Written by Jason Vermes with files from The Associated Press. Interviews produced by Samira Moyheddin and Sarah Jackson.