As if honeybees didn’t have it hard enough, a new invasive insect is out to chop off their heads and feed the bodies to their young in preparation to crown a new queen next year.

The Asian giant hornet — sometimes called the killer hornet — debuted in Northwest Washington last fall, alarming entomologists and prompting Washington State University scientists to ask citizens to help trap the bug to determine its travel patterns, eliminate in-ground dens and prevent them from getting a toehold here.

The insect has not yet been discovered anywhere south of Bellingham—and scientists want to keep it that way.

The first hornet was discovered by a beekeeper in Blaine, who noticed a pile of bee heads at the base of a hive last November. A second insect was found in Bellingham, and there have been two unconfirmed sightings. Two others have been found in White Rock and Vancouver Island, British Columbia.

How they got here is one of many unknowns.

The search for the hives continues, and WSU researchers are asking for help.

“All the people who reached out to us, it was because something they didn’t recognize,” said Chris Looney, an entomologist with the state Department of Agriculture who spoke to the Washington Invasive Species Council in February. “They found something — ‘What’s this enormous thing on my doorstep?’ Lots and lots of exotic pests are detected that way. We discover as much that way as we do our surveys.”

In the midst of the global coronavirus pandemic, the news hit social media like a swarm of bees, blowing the event out of proportion; two hornets hardly merits an invasion.

Bzzzzzzzzz

The hornet is the world’s largest and most ferocious looking, with a 3-inch wingspan similar to that of a dragonfly and teardrop-shaped eyes. The 2-inch-long body features orange and black stripes and its sting is said to feel like a red-hot tack stabbing the body; even protective bee suits are no match for its stinger.

“They’re notorious for attacks on social insects, especially honeybees,” Looney said. “They find one, and at some point, hornets begin to focus on the hive, mark it with pheromones and essentially come in groups and capture every adult bee, kill them and throw them on the ground.

“They literally slaughter all the workers. Then they treat the hive like their own. In this occupation phase, they treat (the hive) like a grocery store; they pull the larvae and pupae and return them to their nest for food. And the bees are woefully ill-equipped to deal with it in single combat. They’re sitting bees.”

What the detritus hornets leave behind can look similar to that left by an invading vole, mice or yellowjacket and might not, at this point, indicate a hornet is in the area.

Some hornets look like the Asian insect, as well, particularly the cicada killer hornet, which is differentiated by its small head and spots and stripes, not merely stripes, on its abdomen.

The hornet is native to Japan, and since monitoring of it began in 1977, the hornets have traveled about 80 miles north in Asia. Washington has a similar temperate climate, making the region an ideal environment in which the hornet could take hold, Looney said.

The bug typically emerges from soil dens — although some winter down in wood piles — in mid-March through late May.

“Large caterpillars, katydids, honey bees; they’re all fair game,” Looney said. “They have a special predilection for honeybees. But honey bees only? Mason bees? Bumble bees? It seems like it’d be a good food source, but the answer is, we just don’t know.”

As the colony matures and approaches its reproductive phase in late summer, the hornets turn their attention to bees. And oftentimes, the hornet kills for the sake of killing.

“They attack,” Looney said. “A couple dozen hornets in one day can kill an entire hive.”

While the two hornets verified in the United States were found near the Canada border, they could travel south, although Looney admitted scientists don’t know how far they will go.

A similar invasive hornet in Europe travels about 20 miles—making it unlikely the Olympic Peninsula would see an infestation any time soon.

They’ll attack people, as well; 40 to 50 people are killed each year in Asia by repeated stings and the poisonous venom that kills skin cells, creating holes in the site of the bite.

“Its size allows it to administer more venom in a single sting than species we’re used to dealing with,” Looney said. “The potential to get stung is pretty high if you’re around them. The hornet can sting you repeatedly and they certainly will. They are not to be trifled with.”

Those with bee allergies can have worse reactions, as well.

“If you encounter these? Run away,” Looney said. “That’s the correct response.”

The Pacific Northwest

The two verified insect sightings near Canada last fall were both worker bees, indicating a hive was somewhere nearby.

“Based on a similar species introduced in Europe in 2004, by 2018, all of France, the Iberian Peninsula, Italy, Great Britain (had sightings),” Looney said. “They traveled 60 kilometers a year.”

That travel could have been assisted by humans, if the hornet had gotten into a vehicle or its cargo and been transported, or it could have slowly made its way through the continent.

That is a significant economic factor, Looney noted.

Based on work done in Japan, researchers here believe the hornet will be attracted to the sap in oak, alder and cherry trees.

“We never know if this is going to work,” he admitted. “There’s some evidence it’s been effective in Japan. A more conventional approach might just be to use a lot of traps, use the public. We are also looking at making pheromone traps. We don’t know how effective it’ll be. It’s essentially a random fishing expedition.”

Late summer would be the best time to find the dens, he said, because the hornets haven’t had a chance to reach their reproductive stage.

“In Europe and Asia, they’ve had decent success with radar tags,” he said of small tracking devices typically attached to small birds. “But in Europe, they nest in trees. We don’t know if radar can go through ground or thick brush.”

Once they believe they’re close to a nest, scientists might try thermal imaging to find the hornets, as the insects bring their nest temperatures to about 86 degrees.

“We think it’ll be effective, but we’re not quite sure once they go underground,” Looney said. “We literally don’t know.”

Another option considered was using K9 dogs trained to sniff out bumblebees.

“Absolutely. But, there are no hornet suits for dogs,” Looney said. “It would seem like a real disaster to get an expensive, well-trained dog to get his nose in a nest.”

Economic costs

Honeybees are already threatened by global warming and pesticide use.

“This would be one more negative pressure applied to our already stressed honey bee industry,” said Washington State University entomologist and bee scientist Brandon Hopkins. “It would certainly lead to increased annual colony losses and additional work and costs on beekeepers as they work to defend against the threat.”

“Initially, it will indirectly affect crops produced on the west side of the state: blueberries, raspberries, cranberries,” Hopkins said. “Those crops do have the advantage of being pollinated early when the wasp life cycle will make them less of a threat to those colonies.

“After that, vegetable seed pollination for squash and pumpkins require a large number of colonies and because those crops bloom a little later in the season, the hornet numbers will have grown and in turn, pose a greater threat to colonies. There is the potential that beekeepers decide that performing pollination in these areas are not worth the risk and so choose to stay away from those crops, driving up pollination costs or reducing crop yields.”

Bzzzz-tt

Currently, researchers are focusing hornet-sighting efforts in Whatcom, San Juan and Skagit counties, but urge anyone who’s interested to participate, Hopkins said.

“We desperately hope it’s not anywhere else,” Looney said. “We’ve only had two confirmed specimens, so we don’t know what the actual range is. They could be on the (Olympic) Peninsula; they could be in lots and lots of places we have no clue they’re in, and the only way we discover them is someone telling us they found them.”

When researchers locate a nest — and no citizen should try to address the situation — they will wait until nightfall, sedate the hornets with carbon dioxide and eradicate them.

The U.S. Department of Agriculture is assisting, as well.

“Within a few weeks, they had a thorough, researched document,” Looney said. “They’re reviewing requests for emergency and survey funding. We anticipate the project to last three years. The best case scenario is to destroy and confirm we have no more established in the Pacific Northwest. The worst case … this would go much longer.”

University scientists are asking interested residents in various counties, including Jefferson County, to build and mount traps for the hornet in a 17- or 34-week study period.

“Traps without a sighting is beneficial, but a huge amount of traps will (capture no hornets),” Looney said. “It comes down to how to keep people engaged and not disappointed and sad because their trap is empty.

“And this is our window (of time) to keep it from establishing,” he added. “If we can’t do it in the next couple of years, it probably can’t be done.”

Anyone seeing a live hornet should stay away from it and contact the state Department of Agriculture at 800-443-6684. Pest companies called to eradicate a den are asked to call first, as well. Anyone stung by the hornet, particularly those with bee allergies, should go to their nearest emergency room.

And those interested in setting traps can visit https://agr.wa.gov/departments/insects-pests-and-weeds/insects/hornets/trapping for information about how to proceed.