Good news! The invasive insect formerly known as the “murder hornet” might soon be under control in Washington state. After wrapping up its pest trapping season for 2022, the Washington State Department of Agriculture (WSDA) reported no sightings of the northern giant hornet.
“When it comes to the pests that we survey for, the best news is no news,” Sven Spichiger, WSDA managing entomologist, said in a press release yesterday.
It is still too early to declare complete victory over the hornet. It takes three years of no sightings for the pest to be considered “eradicated” under federal guidelines. But this is the first year without sightings since the first report of a northern giant hornet in Washington set off alarm bells in 2019.
“The best news is no news”
Washington officials feared the hornets, native to Asia, might decimate honeybee hives if they gained a foothold in the state. Just a few hornets can wreck an entire hive in a “matter of hours,” according to the WSDA. When in “slaughter phase,” the giant hornets go on a decapitation spree. Eventually the hornets take the hive as their own and use the headless dead to feed their own young. So you can see how the little critter got the nickname “murder hornet.”
Bees in Japan have learned how to defend against the invaders using their numbers to overcome the larger hornets. The bees will swarm around an individual hornet, overheating and suffocating the hornet to death. But North American bees haven’t learned to wage war against the invasive species yet.
To see some of this in action, there’s a documentary called Nest Zero you can watch. It’s a nail-biter; Washington’s Public Affairs Network, TVW, won an Emmy for it last year.
All the publicity has helped the state mobilize against the invading hornets. Because when you’ve got murderous hornets on the loose, your friendly neighborhood entomologists might need some help. Washington state residents reported the first northern giant hornet sightings in 2019, 2020, and 2021.
For the record: “murderous” applies mostly to bees. It’s not common for the northern giant hornet to go after people or pets. Scientists argued that the “murder hornet” moniker was inaccurate since the bees aren’t aggressive to humans. For a while, the hornets went by the common name “Asian giant hornet.” But the Entomological Society of America changed that to northern giant hornet this year following concerns it could stoke anti-Asian sentiment.
“Giant” is pretty accurate to the hornet’s impressive physique, though. This species of hornet is the largest in the world, growing up to two inches long — which, thankfully, makes them easier to spot. They have stingers long enough to pierce a beekeeping suit and can sting repeatedly. Their venom is also more toxic than that of bees.
This year, the state launched an “adopt a wasp” program to enlist the help of citizen scientists in finding the invasive species. Some northern giant hornets had been seen attacking paper wasp nests in Washington, so the WSDA asked residents to “adopt” a paper wasp nest, committing to visit and observe it at least once a week and report any signs of giant hornets.
WSDA entomologists were able to find and destroy a northern giant hornet nest for the first time in October 2020. They used dental floss to tie a radio tag to a hornet and follow it home. Destroying the nest involved sealing off entrances, wrapping the nest and the tree it was in with cellophane, and then inserting a vacuum hose to suck up the hornets. Then they pumped CO2 into the tree to kill any hornets still hiding inside.
Heading into 2023, the entomologists are staying vigilant. The WSDA is still asking the public to keep an eye out for the northern giant hornet and report any sightings. They’ve got an online Hornet Watch Report Form, and residents can email email@example.com or call 1-800-443-6684.
“While not detecting any hornets this year is promising, the work to ensure they are eradicated is not over yet,” Spichiger said.