- Author: Kathy Keatley Garvey
Should we now worry about those Asian giant hornets becoming residents of our Golden State?
Kimsey, a global authority on wasps, bees and other insects, is a two-term past president of the International Society of Hymenopterists. She recently co-authored “The Diversity of Hornets in the Genus Vespa (Hymenoptera: Vespidae; Vespinae); Their Importance and Interceptions in the United States” in the journal Insect Systematics and Diversity with two other entomologists: lead author Allan Smith-Pardo, U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS); and James Carpenter of the American Museum of Natural History's Division of Invertebrate Zoology.
The latest news: the Washington State Department of Agriculture (WSDA) announced Oct. 24 that a nest was discovered and destroyed in a tree cavity near Blaine, Wash. This marked Washington's first known nest of Vespa mandarinia. North America's first detected colony of the giant hornets was destroyed in September 2019 on Vancouver Island, British Columbia. A single V. mandarinia was found dead in Blaine, Wash., in December 2019.
But to worry. The hornet won't like California's hot, dry summers and lack of rainfall.
As Kimsey told reporter Kellie Hwang of the San Francisco Chronicle: "It is exceedingly unlikely that these hornets can establish in California. If you look at where they're found in their native range in southern Asia, this region has summer rain. I think California is too dry, except perhaps along the far northern coast.”
Washington State University (WSU) entomologists and their colleagues agree. They recently "examined more than 200 records from the hornet's native range in Japan, South Korea, and Taiwan, then used a set of ecological models incorporating climate data to predict likely global habitat across six continents," according to a WSU news release.
They found that "Asian giant hornets are most likely to thrive in places with warm summers, mild winters, and high rainfall. Extreme heat is lethal, so their most suitable habitats are in regions with a maximum temperature of 102 degrees Fahrenheit. Based on those factors, suitable habitat for the giant hornet exists along much of the U.S. west and east coasts, adjacent parts of Canada, much of Europe, northwestern and southeastern South America, central Africa, eastern Australia, and most parts of New Zealand."
"Much of the interior of the U.S. is inhospitable to the hornet due to extremes of heat, cold, and low rainfall," the news release related. "This includes the eastern parts of Washington state and British Columbia, as well as California's Central Valley, all of which have major fruit and nut crops that rely on honey bee pollination."
Scientists dislike the sensationalized name "murder hornets" (so named because insects can quickly destroy a honey bee colony). The insects defend their colony when it is threatened, but generally will not attack people or pets, according to WSDA. The fear is there, though. "Their stinger is longer than that of a honeybee and their venom is more toxic," WSDA says. "They can also sting repeatedly."
But "murder hornets?"
Maybe we should just call them "giant hornets," you think?
- Author: Kathy Keatley Garvey
Just when folks were beginning to think "it may be over and done" regarding Asian giant hornet sightings, it's not.
The Washington State Department of Agriculture (WSDA) has just trapped its first Asian giant hornet, Vespa mandarinia, which the news media dubbed "the murder hornet." (It's a name that makes entomologists cringe.)
In a news release published July 31, officials announced that they found a hornet in a WSDA trap set near Birch Bay in Whatcom County. "WSDA trappers checked the bottle trap on July 14 and submitted the contents for processing at WSDA's entomology lab. The hornet was identified during processing on July 29. This was the first hornet to be detected in a trap, rather than found in the environment as the state's five previous confirmed sightings were."
Sven Spichiger, managing entomologist for the department, said: “This is encouraging because it means we know that the traps work. But it also means we have work to do."
So WSDA will now use infrared cameras and place additional traps in the area. These are special traps to catch them alive. From the press release: "If they catch live hornets, the department will attempt to tag and track them back to their colony. Once located, the agency will eradicate the colony."
"WSDA hopes to find and destroy the nest by mid-September before the colony would begin creating new reproducing queens and drones. Until that time, the colony will only contain the queen and worker Asian giant hornets. Destroying the nest before new queens emerge and mate will prevent the spread of this invasive pest."
All in all, WSDA, citizen scientists and others have set out more than 1300 traps in Washington state.
"Those interested in trapping can still build and set traps on their own property," according to the news release. "Traps require weekly bait replacement and a commitment to mail the trap contents to WSDA if bees or wasps are collected. If a citizen scientist traps a live Asian giant hornet, they should call the WSDA Pest Program hotline at 1-800-443-6684."
"Because the number of Asian giant hornet workers increases as a colony develops, residents should be most likely to see an Asian giant hornet in August and September. If you think you have seen one, report it at agr.wa.gov/hornets. Provide as much detail as you can about what you saw and where. Also, include a photo if you can safely obtain one, and if you come across a dead specimen keep it for potential testing."
Noted hymenopterist Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis, has been following the confirmed and unconfirmed sightings and recently talked about the Asian giant hornets on a podcast with urban entomologist Michael Bentley on his BugBytes podcast. Click here to listen.
Bentley serves as the director of training and education for the National Pest Management Association (NPMA), headquartered in Fairfax, Va., and hosts NPMA's BugBytes. Kimsey, a global authority on wasps, bees and other insects, is a two-term past president of the International Society of Hymenopterists.
They talked about the history of the hornet, its biology, its range, its behavior, its stings, and the news media frenzy.
What was known then: two incidents occurred in North America last year. A single colony of the Asian giant hornet was found and destroyed Sept. 18, 2019 in Nanaimo, Vancouver Island, Canada, and a single dead hornet was found Dec. 8, 2019 in nearby Blaine, Wash. Kimsey says they probably hitchhiked on a cargo ship,
Asian giant hornets, originating from Asia, can decimate a honey bee colony, and the Washington beekeeping industry is concerned that these invasive pests may become established here.
Meanwhile, many so-called "murder hornets" have turned out to be yellow jackets, European paper wasps, hover flies, hoverflies, moths, circadas and even a Jerusalem cricket (potato bug). Stephane De Greef, a Belgium-born entomology advocate, traveler, field guide, and photographer, earlier called the frenzy "a bloody dumpster fire." He launched a fun (and informative) Facebook page, Is This a Murder Hornet?" In a Facebook comment today, he pointed out that the findings are all within a 10-mile radius (see the map he posted below).