The internet has been abuzz with concern following news that Asian giant hornets, which have earned the extravagant nickname ‘murder hornets’ thanks to their proficiency for killing honey bees, were observed in the United States for the first time in December of 2019. As reported by the New York Times, the hornets were observed near Blaine, Washington. The Asian giant hornet was also sighted in 2019 in British Columbia, when a lone nest of the species was found and destroyed. Despite their fear-inducing nickname, experts have stated that the Asian giant hornet is unlikely to establish and spread eastward through Canada into cottage country.
The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) says “Vespa mandarinia (or the Asian giant hornet) has not been confirmed in Ontario. The only confirmations of these in North America were in B.C. and Washington State at the end of 2019. All specimens reported in Ontario to date have been confirmed to be other species of hornet or wasp that are already present in Ontario.”
The Asian giant hornets that were sighted on the west coast of North America may have come over from Asia in a shipping container, says Brent Sinclair, from the Biology Department at Western University. But because the hornets are about two inches long, the species isn’t often accidentally transported. Even if they do make their way across the Pacific Ocean by accident Sinclair says, “we’re not seeing large numbers of them, and there’s no evidence they’ve established and spread.”
The New York Times reports that up to 50 people die from Asian giant hornet stings each year in Japan. Sinclair says the deaths probably are a result of anaphylactic shock, in the same way that stings from yellow jackets and other hornets can cause severe allergic reactions.
The big threat the Asian giant hornets pose is not to humans, but to honey bees. Sinclair says that the commercial European honey bees reared in Canada don’t have good defences against attacks from the hornet, and that a nest of hornets could wipe out a hive of honey bees in three days.
Sinclair has observed Asian giant hornets hunting bees at commercial hives in south-eastern China. “They’re really identifiable by their behaviour,” he says. The hornets hang around hives, grab worker bees as they fly and carry them off to a tree where they bite their heads off. “There’s not many things you see that hunt honey bees at the hive like that.”
Because honey bees are raised as livestock, if Asian giant hornets were to spread throughout Canada they would pose a significant threat to agricultural practices. The OMAFRA says that “Beekeepers in Ontario have been informed of the status of the Asian Giant Hornet in western North America. Beekeepers can call the Agricultural Information Contact Centre at 1-877-424-1300 if they have questions.”
While it is extremely unlikely to see an Asian giant hornet pop up in Ontario this summer, if you come across an unknown insect, Sinclair highly recommends taking a photo and uploading it to the iNaturalist app. The app is a great tool to help you identify insect species, he says.
It’s also important to remember that with a showy nickname like ‘murder hornet’, the Asian giant hornet is stealing the spotlight away from other invasive insects creeping their way into Canada that pose a significant threat to the environment in cottage country. Invasive forest pests that infect and kill trees, such as Emerald Ash borer, Asian longhorn beetle, and Hemlock wolly adelgid, spread when people move infested wood material like firewood, lumber, and wood chips into new areas. “If people want to do something to prevent invasive species that are going to affect their lives in cottage country,” says Sinclair, “don’t move firewood.”
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