Slim chance of giant hornets becoming established: experts
Fire up the backyard BBQ without fear of a deadly sting. That hike in the forest or walk in the park should be just fine, too.
There’s no need for Canadians to worry for their personal safety with the arrival of so-called “murder hornets” on the West Coast, experts say.
“They’re kind of a bully to other insects, but not to us,” said entomologist Justin Schmidt. “They don’t really attack us. It’d be really hard to get stung unless they get established, which I would say is a nil to zero chance.”
The insect — proper name: Asian giant hornet (Vespa mandarinia) — cuts an imposing figure. As big as a man’s thumb, it boasts a wing span of up to seven centimetres, a large orange head, black eyes and a sting that could seriously injure or even kill a person.
However, despite the dubious nickname that has been poohpoohed by experts, murder hornets are not exactly taking over on these shores. But if they do manage to re-emerge, they could be a real threat to honeybees.
The hornets are normally found in the forests and low mountains of eastern and southeast Asia, and it remains unclear how they arrived in North America.
Three Asian giant hornets were spotted in B.C. for the first time last August in the Nanaimo area, the province’s agriculture ministry said. The single nest was spotted and destroyed, but a specimen was found last November in White Rock and two specimens were found in December at Blaine, Washington.
B.C. classifies the Asian giant hornet as a “serious honeybee predator.” If it returns, it has the potential to affect that population.
“They have massive heads with these giant mandibles and they just chop [the bees] in half,” said Gard Otis, an adjunct professor at the University of Guelph specializing in bee behaviour and forest entomology. “They just cut their heads off, cut their bodies in half, and you end up with a slaughter on the ground in front of the hive.
They kill all the adult bees and end up with honey, larvae, pupae, Otis said. “It’s like they just stocked up the refrigerator for the next pandemic.”
Farmers in the southern B.C. and northern Washington area depend on honeybees to pollinate crops such as apples, blueberries and cherries.
The Asian giant hornet is not a pest regulated at the federal level, so it falls under the mandate of the province, the Canadian Food Inspection Agency said this week.
B.C. issued an information bulletin in March asking residents near the border to be on the lookout. The province has also said it planned to place hornet traps near the border and distribute pest-alert notices to area residents.
There has not been a reported sighting so far this year.
“I don’t think really we need to worry too much about them,” said insect-biology expert Peter Kevan, a professor emeritus at the University of Guelph. “I think that whoever gave them the name ‘murder hornet’ is just trying to get some hyperbole in the press.” Mission accomplished. Fear not, experts say, as the Asian giant hornet isn’t interested in humans and last year’s sightings were very limited. “It’s very large and it’s very defensive of its nests,” Kevan said from Cambridge, Ont. “If people leave it alone, it’ll leave them alone because really it’s a carnivore.”
The wooded habitat where it was spotted offers suitable nesting grounds. The hornet’s life cycle begins in April when queens emerge from hibernation, feed on sap and fruit, and look for underground dens.
They hunt insects and are generally not looking to engage with people, pets or large animals, the B.C. Agriculture Ministry said.
Disturbing a nest, however, will put them on the attack. And a sting packs a mighty wallop.
Schmidt, an adjunct scientist at the University of Arizona, created the Schmidt Sting Pain Index to rate the relative pain levels of different stings. A 2.5 rating for a trap-jaw ant sting is comparable to having a rat trap snap a fingernail in half. Schmidt pegged the Asian giant hornet sting at a potent 3.0 or even a 3.5.
“It has 10 times the venom of a honeybee easily, probably 20 times the average yellowjacket,” he said from Tucson, Arizona.
Otis said he was stung in 2013 while doing research in Vietnam. He recalled a sharp initial penetration in his big toe and a fierce blast of pain setting in about 30 seconds later. “It was this incredible searing pain,” he said from Guelph, Ont.
Many insects introduced to this foreign environment don’t have enough genetic diversity in the initial group of wasps to sustain their numbers, Otis said.
Schmidt agreed it was unlikely they would prosper in North America. “They’re probably not going to get established, they’re just going to get eradicated,” Schmidt said.