No horror of 2020 could top COVID-19. But “murder hornets” came close.
The Asian giant hornet—a nearly 2-inch hornet native to Asia, scientifically known as the Vespa mandarinia and terrifyingly known as the “murder hornet”—was found in the U.S. for the first time in late 2019, with scientists finding the dreaded insect scattered throughout Washington’s Whatcom County last year, including a large nest. It became an icon of a hellscape time, with people across the U.S. wondering if the hornets might find them next.
That continued in June this year when a dead hornet was found in Washington’s Snohomish County. Officials classified that hornet as one from last season (the season starts in July through at least late November), but it still managed to kickstart fears as another season looms.
A year after their emergence, there is still uncertainty as to how Asian giant hornets entered the U.S. But researchers at the Washington State Department of Agriculture, along with the U.S. Department of Agriculture, are developing a better understanding of what they do and don’t know about the hornets—and how to combat them.
“It’s not like there’s a playbook for this,” said Karla Salp, a public engagement specialist with the Washington State Department of Agriculture. “There’s no science to pull from to say ‘This is how fast they spread’ or ‘You’re beyond the point of no return.’”
The state has launched an outreach program to educate residents on the hornets and how to get involved in eradicating them. Its work is partly funded through the USDA’s Animal and Plant Inspection Service, which has provided $1,126,183, while the state has provided $188,000.
That includes the state’s “Citizen Scientists” program, where residents lay traps in hopes of catching one of the killer insects.
“We have a very engaged public that’s giving us a leg up on our way to eradicating Asian giant hornets,” Salp said. But citizen scientists have set 587 traps as of Friday, far short of last year’s 1,500. The state attributes that to the lack of interest from the public this year, though it expects to see more as the season progresses.
Much of the state’s focus centers on eight “target counties” where hornets have been detected, are adjacent to, or where it’s had suspicious reports that it could not rule out. Those counties are Whatcom, Island, Skagit, San Juan, Snohomish, King, Clallam, and Jefferson.
The state set up 737 traps between Whatcom and Snohomish counties as of Friday, with at least 1,100 traps expected to be placed in those two counties alone.
Jacqueline Serrano, a research entomologist with the USDA’s Agricultural Research Service, is part of a team developing traps for the Asian giant hornet. They’re using hornet samples and a gas chromatograph, a machine that measures the content levels of chemical components, to determine what the Asian giant hornet may be attracted to.
The process will allow them to create synthetic versions of the hornet’s attractants to lure–and snuff—them out. The issue, paradoxically, is the lack of live hornets to test them on this year, as most sightings were between August and September last year.
“It’s sort of a needle-in-a-haystack kind of approach,” Serrano, who is based in Washington state, said. “We’re trying a bunch of different things hoping that one thing is going to work.”
The biggest worry of the hornets isn’t the danger they pose to humans but instead their threat to honeybees and crops. Hornets tend to pulverize honeybee nests, beheading the bees and transporting their newfound food back to their nests to feed their young.
That’s led researchers within the ARS to break down the hornet’s genome, or its genetic composition. Doing so could help create forensic tools to determine if dead honeybees hives were caused by hornets, like CSI for insects, ARS computational biologist Anna Childers said.
“By having a genome assembly, we’re going to have a much more accurate method of identifying this hornet versus other closely related wasps,” like the regular Asian or European hornet, Childers told The Daily Beast.
She leads the Ag100Pest Initiative, which analyzes genomes of invasive pests. She has spent the last year breaking down the genome and comparing the hornet to other subpopulations in Asia.
Childers said the hornet’s genome will help pinpoint how likely it is to adapt to the state—and whether there is even a population large enough to become a permanent fixture.
“Some insects in general have genome features that allow them to more rapidly diversify, which allows them to more quickly adapt to new environments,” she said. “So we’re interested in seeing if this is true in Asian giant hornet.”
To aid this work, Childers wants to get samples of other Asian giant hornets found throughout Asia so researchers can determine which ones are most similar to those found in the U.S.. Despite sharing common traits, an Asian giant hornet found in one country in Asia could be different than one found in another. Further complicating this effort is the fact that people ship the insect between countries for food or therapeutics.
“Relying on a single piece of data could be dangerous, because if you collect a single hornet from an area where there may be shipping of this format, then your piece of information could be incorrect,” Childers said.
As ARS builds the genome profiles of the different Asian samples, Childers said, it can analyze where the hornets in the U.S. originated from, see how big their U.S. population is, and examine and compare their genetic functions to those from Asia. That includes what makes their nests so large, what makes them so aggressive, and how their immune systems compare to each other. A report on that is expected later this year.
Another goal is to help develop potential pesticides to specifically target Asian giant hornets.
Michelle Heck, a research molecular biologist with the USDA, is studying the hornet’s venom to examine its proteins. One of the goals is to see whether the fairly toxic venom could be repurposed into a pesticide against Asian giant hornets and other insects.
“Insect venom toxins are very useful for the development of novel insecticides,” Heck said. “Understanding what peptides are using the venom to immobilize their prey could be useful for developing new types of insecticides.”
Heck’s research is also looking into how the hornet manages environmental pathogens like fungi and bacteria. As she looks into what pathogens latch on to the hornet, she hopes to see whether they can also be used to fight them.
Despite progress on control measures, the objective is complete eradication, Salp, from Washington’s Department of Agriculture, said.
However, state officials recognize the challenge that presents. Asian giant hornets tend to nest in areas often undisturbed by people, like ground and tree cavities, making them harder to detect, Salp said.
“There’s so much habitat for them there, so much of it that is not readily visited by humans,” she said. “There’s many places they could thrive. It’s going to be very challenging to eradicate them, but we are hopeful.”
One thing unanimously agreed upon by experts: they hate the name “murder hornets.”
“Even when they’re preying on honeybees or other insects, they’re not murdering them,” Heck, the molecular biologist, said. “They’re turning them into food for their young. That’s not to downplay the seriousness of it, but I don’t think murder is the right term.”