Asian Giant Hornet Invasion Threatens Honey Bees in Pacific Northwest

As if honey bees didn’t have enough to contend with, from pesticides to bacterial pathogens, another nemesis has emerged in the Pacific Northwest, one capable of freaking out humans, too.

It’s called the Asian giant hornet — and is also known as the yak-killer hornet, the commander wasp in Korea and the tiger head bee in Taiwan, according to experts.

As the names indicate, the hornets are indigenous to Asia, but some appeared for the first time this month in Washington State, where agricultural officials have issued a pest alert and warned that the hornets pose a threat to honeybees.

They showed up in British Columbia in August, prompting a similar advisory from the Canadian province’s agriculture ministry.

The reputation of the mammoth hornets — which are distinguished by their yellow heads and can be nearly two inches long with a wingspan of up to three inches — precedes them.

May Berenbaum, the head of the entomology department at the University of Illinois at Urbana-Champaign, said on Monday that the hornets can wipe out an entire beehive. They’re generally not aggressive toward humans but their stingers are about six millimeters long and can inflict substantial pain and possibly even death in someone who is allergic, she said.

“You want to talk about beepocalypse,” Professor Berenbaum said. “They are sworn enemies of honey bees. I would say a bee’s worst nightmare. Probably the worst nightmare of a lot of people, too.”

A resident of Blaine, Wash., which is on the Canadian border and about 30 miles south of Vancouver, found a dead hornet on Dec. 8 that was then collected by state entomologists, the Washington State Department of Agriculture said. The agency said it confirmed that the specimen was an Asian giant hornet.

The resident reported that a second hornet had been flying near a hummingbird feeder before it disappeared into a nearby forest, officials said.

“Though they are typically not interested in humans, pets or large animals, they can inflict a nasty sting if threatened or their nest is disturbed,” the state agency said in the pest alert, on Dec. 19.

In British Columbia, officials advised residents to report any sightings of the hornets to the Ministry of Agriculture and take photographs if possible.

“Asian Hornets are not interested in humans, pets and large animals,” the ministry said. “They hunt insects for food. The only time hornets will attack is when their nest is disturbed. Asian Hornets will feed on honeybees and are capable of destroying hives in a short time period.”

Insect experts said that the pests, which are among the largest hornets, are usually dormant at this time of year. They make their nests in the ground.

Professor Berenbaum said there was a distinct possibility that the hornets were “stowaways” on a ship that crossed the Pacific and could be attracted to any kind of sugary fermenting cargo. They could have also nested in any soil used as ballast material in ships, she said.

“I can’t imagine why anyone would deliberately bring this over,” she said. “There are so many ways insects can be accidentally transported.”

Unlike honey bees in North America, honey bees in Asia have developed their own defenses against the Asian giant hornet as they have evolved, Professor Berenbaum said.

“When a hornet gets into the nest, they mob the hornet and generate enough body heat to kill it,” she said.

In 2014, she wrote an essay titled “Spirits of the Hive” for the American Entomologist, the journal of the Entomological Society of America, about how Asian giant hornets are steeped in liquor by distillers in Asia. A Taiwanese graduate student once presented her with a bottle of Asian hornet wine.

The professor also keeps a specimen of the Asian giant hornet.

“I have a Lucite paperweight with one in there,” she said. “It kind of showcases how enormous they are.”