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Invasive species

by Wyoming Livestock Roundup

Asian giant hornet found in western U.S. 

After monitoring multiple independent hives on the Canadian border, the Asian giant hornet has been reported in Washington State. 

Dubbed the “murder hornet” by U.S. popular media, the insect is native to Japan and has been known to kill due to its extremely potent venom, according to Washington State Department of Agriculture (WSDA). 

While American press is sharing the insect alone kills up to 50 people per year, Japanese sources cite only 12 people per year die of insect stings, which includes all wasps and bees.

WSDA believes the insects made their way to North America via cargo ships from China. At more than two inches long, the hornets are the largest in the world.

The hornets are particularly hard on bee colonies as they are able to decimate entire colonies to support their own colonies. They are known to decapitate honey bees and consume the remaining portion of the body.

However, the insect does not target honey 

bees. West Virginia University Entomologist Brian Lovett notes the creature will attack a variety of insects including caterpillars and other social insects.

According to Washington State University (WSU) Extension, samples of Asian giant hornet were positively identified after being found in Blaine, Wash. in December 2019. 

“This is the first confirmed U.S. sighting of this insect in the wild and only the third in North America, after specimens were found in Nanaimo and White Rock, British Columbia earlier in 2019,” WSU reports. “After the original detection, three more potential Asian giant hornet sightings were reported south of Blaine and in Bellingham in late April. Two of these reports were of Asian giant hornet attacking colonies of honey bees, with beekeepers observing potential hornet activity as far back as October.”

Likelihood of spread

Entomologists across the country have offered their expert opinions and advice on the discovery of the dangerous hornet. However, there seems to be a mixed bag of opinions on whether the insect will spread across the U.S.  

University of Wyoming (UW) Extension Entomologist Scott Schell notes producers in Wyoming are unlikely to see this pest anytime soon. 

“We have a lot more insects that will likely cause more damage than that beast ever will,” Schell says. 

Fellow UW Entomologist Randa Jabbour notes it is unlikely this will be a problem in Wyoming anytime soon, but beekeepers should be aware of the issue and be vigilant with their hives. 

Colorado State University Entomologist Whitney Crenshaw believes the media coverage of the insect is “sensationalist” and is confident the creature will be eradicated in Washington State before it is able to travel further east. 

“This is a sensational story, but here are a couple of things to keep in mind,” Crenshaw says. “First of all, within the United States the Asian giant hornet is presently found in only a small area of northeast Washington State and, perhaps an adjacent area of British Columbia.” 

He continues, “There are efforts to try and eradicate it, but it is still too early to know if that is possible. A variety of traps and controls have been developed for this in Asia and these can be adapted to try and use here.”

Crenshaw notes this insect is adapted to low-elevation woodland areas, which are not present in Colorado. The wasp is also not a good “hitchhiker” like the European wasp, and therefore is less likely to spread. 

Some entomologists are less confident the wasp will be eradicated before spreading. University of Arizona Entomologist Katy Prudic notes there are a lot of factors that could influence the insects’ spread.

“It depends on how many have been introduced, when they were introduced and where they were introduced. It also depends on how well we can detect them in the landscape and remove them,” Prudic explains. “All of those factors are quickly changing, which is why reporting observations to local officials is important.” 

“Because some people may not know the difference between an Asian giant hornet and a tarantula hawk, I recommend using a smartphone application like Seek to help identify the hornet,” Prudic says. “This will help local officials from becoming overwhelmed with false observations of an Asian giant hornet.”

The Entomological Society of America notes the appearance of the Asian giant hornet should be a reminder of the ongoing challenge to prevent and respond to invasive insect and anthropoid species.

About the hornet 

North Carolina State University Extension Entomologist Michael Waldvogel notes the hornets somewhat resemble a common yellowjacket but much bigger. 

“Queens of the Asian giant hornet are more than two-inches long, while the workers are about an inch and a half long,” he says. “The Asian giant hornets have an almost entirely yellow-orange colored head. They have a dark thorax, the body section where the wings and legs attach, and the abdomen has dark brown and black bands.”

Purdue University Extension reports the insect is five times the size of a honey bee and 20 times the weight, with a large adult being able to kill as many as 40 honey bees per minute using its large mandible.

“Asian giant hornets create nests in the ground, taking advantage of existing structures such as hollow trees or rodent tunnels,” WSU says. “They aggressively attack honey bees and a small group of them can destroy an entire colony, and as such are a serious concern for beehives and native pollinators. Asian giant hornets can be confused with other species in the same genus, so positive identification is needed to confirm their presence.”

WSU notes the Asian giant hornet is also a potential human health concern as their venom is very toxic and they will attack humans if threatened.

Callie Hanson is the managing editor of the Wyoming Livestock Roundup. Send comments on this article to

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