'Murder hornets' may spread east from B.C. if not eradicated, entomologist says

Missing: One border-jumping murder hornet Washington State officials believe a tagged murder hornet has made its way into B.C.

TORONTO — A Canadian entomologist says Asian giant hornets -- also known as ‘murder hornets’ -- have only been reported in B.C., but may spread to other provinces if successful colonies are established.

"If [the hornets] survive well in British Columbia, I think the climatic zones that they can survive in would go up into pretty much all of Canada," University of Manitoba entomologist Robert Currie said in a telephone interview with CTVNews.ca on Monday. "They're restricted usually into kind of the warmer areas, but they do have the potential to migrate."

The Asian giant hornet was first spotted in B.C. in August 2019, and this past December in Washington state. Officials in those regions have now issued warnings that the Vespa mandarinia species may be active again this spring as queens emerge from hibernation to build nests and form colonies.

"The hope is that they will be able to eradicate them, but they haven't had a lot of success doing that in other countries. In Canada, if there are only one or two colonies that have been introduced and they haven't been firmly established, then they have caught this soon enough and eradication is definitely a possibility," Currie said.

Carleton University Assistant Professor of Biology Heath MacMillan told CTV's Your Morning that Canadian winters may help prevent Asian hornets from maintaining colonies.

"Across the world, insects differ in kind of how cold tolerant they are. In Canada, we're really fortunate in some ways to have such cold winters because it actually keeps a lot of these pests and invasive species at bay," Heath said on Tuesday. "This giant hornet comes from Southeast Asia, found in Korea and Japan and some in China, but they've been moving northward further into China over the last few years as a result of climate change."

Researchers have nicknamed the Asian insects "murder hornets" because they are the world's largest hornet and can kill humans with multiple bites, according to CTV News science and technology specialist Dan Riskin.

"Sometimes in nature, an animal that looks really scary is actually quite harmless, or an animal that looks quite harmless can be quite scary. This is one of those cases where it looks really scary and it is really scary," Riskin said in an interview with CTV News Channel on Monday.

Riskin said Asian hornets are extremely aggressive and "look like an anime character" with a large red-yellow face and long stingers. The queens of this species can grow over five centimetres long, while other hornet species are usually around 3.5 centimetres. Riskin said an Asian hornet's stinger is so long and sharp that it can pierce through a beekeeper suit.

Despite the terrifying description, Riskin said the hornets are not usually interested in humans or animals. Rather, they eat honeybees -- a significant concern for struggling bee populations that play a vital role in agricultural success in Canada.

"It's a terrible hornet. They come in masses, they attack honeybee colonies where they rip their heads of the honeybees and carry their severed bodies back to their own nests to feed their babies," Riskin said. "And if you tussle with these things, they will sting you often and the venom is extremely painful."

According to Heath, a colony of Asian giant hornets can kill about 40 bees in a minute. However, Heath said the insects are not something Canadians should be worried about right now.

Heath said Asian hornets killed approximately 50 people in China last year. He says this is comparable to the amount of people who die in the U.S. each year from bee stings.

"Right now, no we don't need to be concerned, but absolutely we need to be concerned about monitoring this over the long term because they're less of a problem in terms of actually stinging us as they are in terms of affecting our food supply chain," Heath said.

Despite being known for killing honeybees, Heath said Asian giant hornets should not be called "murder hornets."

"I think [the name] is kind of misleading and it kind of anthropomorphizes them and that makes them seem like they're choosing to murder things. They are like a lion, they're a predator. They decapitate bees and they take their thorax, the muscular part of their body, and they eat it so they're eating meat, they're eating other insects," Heath said.

Experts don't know how these giant hornets that are native to Asia ended up in North America. Currie says they were likely brought here in cargo by accident, or on purpose as a delicacy.

“They probably came over here [from Asia] in soil that was shipped. Maybe a plant that was shipped in potted soil or something like that. The queens overwinter in the soil so it is possible that a queen could be introduced through that method," Currie said.

"The other theory that has been proposed, although there is no concrete evidence, is that they could have been brought over for human consumption as a sort of delicacy. But at this point, we don’t really know exactly how they got in,” he added.

There have been no reported sightings of Asian hornets in Canada yet this year.

However, University of Guelph environmental science professor Stephen Marshall said Asian hornets look similar to European hornets that are common across Canada. He said Asian hornets are also easily confused with sphecius speciosus, most commonly known as cicada killers.

"[European hornets] are huge and intimidating, but not terribly aggressive. I see them occasionally in Ontario, they look much like a huge yellowjacket wasp. I routinely get contacted about supposed Ontario sightings of aggressive Asian species of Vespa, but those sightings invariably turn out to be misidentifications of another large wasp, the cicada killer. Cicada killers are totally non-aggressive, solitary wasps in another family," Marshall told CTVNews.ca via email.

Marshall added that he is not aware of any confirmed cases of hornet species in eastern Canada other than European hornets.

Experts say Asian hornets prefer wooded areas and make their nests in the ground rather than in trees or around buildings. If people stumble upon a nest, officials recommend that they avoid it and leave the area immediately.