Asian giant hornets have probably been living in the U.S. Pacific Northwest for at least eight months now, but not until the New York Times called them “murder hornets” did we think to panic. It’s true that they’re dangerous to people and to beehives, but there’s still time to stop them from becoming established in North America.
What are these strange insects?
The Asian giant hornet, Vespa mandarinia, is a large wasp, about 4 to 5 centimetres long, with black and orange markings. Like other wasps, they are predators. They especially enjoy breaking into beehives, killing the adults, and feasting on the young.
Since they’re so large, they can deliver a significant dose of venom, making them a threat to humans as well. A few stings are excruciating; dozens can put you in the hospital. That said, they mainly sting us when they’re defending themselves or their families. They’re not trying to murder us.
The experts who study these guys don’t really like calling them “murder hornets.” Entomologist Gwen Pearson suggests calling them the “Halloween hornet” to describe their colouring.
Researchers' mixed feelings on "murder hornet" moniker:
"On one hand, it conveys that these insects are a serious threat.. On the other hand, hornets don’t murder the way humans [do]... They’re not malicious. They’re just hungry efficient hunters." —@LadyoftheLeps https://t.co/CjxWey9jGy
— Doug Main (@Douglas_Main) May 4, 2020
How dangerous are they to humans?
They pack more venom than a typical bee or wasp, making their stings more painful and harmful than other stings you may have experienced. They can also sting through standard beekeeping suits.
In Japan, 30 to 50 people die each year from their stings. This study finds that people who died from stings had an average of 59 stings, so you probably shouldn’t panic if you get stung just once.
That said, if you know that you’re allergic to bee stings or other insect venom, you may want to seek medical help just in case.
Where did they come from?
Halloween hornets (I’m gonna go with it) are most at home in East Asia, including forested areas in Japan. We don’t know exactly how they got to the U.S., but a USDA report notes that their pupae are a tasty, portable snack, and that it wouldn’t be surprising if somebody shipped or travelled with pupae meant for food and a few escaped. They also could have come by accident, for example in a shipping container. We really don’t know.
Where are they now?
So far, the hornets have only been spotted in the U.S. Pacific northwest, specifically in British Columbia and Washington state.
Pearson points out that the forests in this area are similar to their native habitat. They also stick to the forests: “they are not going to show up in the city,” she says.
There is still time to stop them
Unlike a certain coronavirus, Halloween hornets are not likely to spread quickly across the country. They’re only a problem in one small region right now, and there’s still time to seek out and destroy the nests before they become fully established.
If these hornets become more common, they could be a threat to commercial beekeepers and to the farm crops that rely on hired beehives. Pearson says we don’t yet know whether they might also be a threat to native bees.
What should I do if I see one?
First of all, Pearson has a warning: don’t try to catch it. Since their stings are painful and potentially dangerous, she advises leaving it alone. There are also plenty of large stripey insects out there that are not dangerous. If you want to be able to confirm what you saw, here’s her advice: “Take a picture and run away.”
Why take a picture? Well, the good news is that you can report these hornets so the experts know exactly where you are. The app iNaturalist is not just a great way to identify plants and animals around you, it also helps scientists track sightings of invasive species.
If you’re in Washington state, there is an invasive insects app, and a website where you can report sightings of invasive insects, both available here. You can also help by building traps for the hornets, which the state notes will work best in late summer to fall in the U.S.
If you think you’ve spotted an Asian hornet, Pearson notes you can always contact your state's agricultural extension and tell them what you saw.