- Author: Kathy Keatley Garvey
Remember the massive media frenzy earlier this year when "the murder hornet" became a household word? The media labeled it that, but let's call it AGH. It's a hornet, not some weaponized insect with super powers that belongs in a B-rated movie seen at a Saturday matinee. Drop the drink! Hold the popcorn!
The peer-reviewed publication is the work of two former UC Davis entomologists now with WSU: honey bee geneticist-researcher Susan Cobey, research associate, Department of Entomology, and Timothy Lawrence, associate professor and Island County Extension director (they are a husband-wife team), along with Michael Jensen, associate professor and Pend Oreille County Extension director.
The first four paragraphs zero in on what this is all about:
"The Asian giant hornet (AGH) or Japanese giant hornet, Vespa mandarinia, recently found in British Columbia, Canada, (B. C. Ministry of Agriculture 2019) and in Washington State (McGann 2019), poses a significant threat to European honey bee (EHB), Apis mellifera, colonies and is a public health issue. The AGH is the world's largest species of hornet (Figure 1; Ono et al. 2003), native to temperate and tropical low mountains and forests of eastern Asia (Matsuura 1991). It appears the hornet is well adapted to conditions in the Pacific Northwest.
"If this hornet becomes established, it will have a severe and damaging impact on the honey bee population, the beekeeping industry, the environment, public health, and the economy. It is critical that we identify, trap, and attempt to eliminate this new pest before it becomes established and widespread. Attempts to contain the spread and eradication of this invasive insect will be most effective by trapping queens during early spring before their nests become established. Another strategy is to locate and destroy nests prior to development of virgin queens and drones in the late summer and fall.
"It is critical that surveying and trapping occur before the fall reproductive and dispersal phase of the hornet. Beekeepers in the field are a crucial line of defense in locating, identifying, and trapping the hornets. Yet, everyone should be on the lookout and report any sightings to local authorities and the Washington State Department of Agriculture.
"Here, we will cover how the AGH will impact the honey bee, give the reader a better understanding of the hornet, outline precautions to take, and first aid if attacked by the hornet."
The fact sheet provides crucial information, including what the public and beekeepers need to know, how to trap the hornets, where to report sightings, and information about the life cycle, the stinger, avoidance, and first aid. It details the public health issue and defines "What is a hornet?"
We've heard folks argue that AGH is a "hornet, not a wasp." Noted hymenopterist Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis, points out that hornets ARE wasps.
WSU Extension defines a hornet this way:
"A hornet is simply a large wasp. Generally, wasps of the class or genus known as Vespa are considered hornets. Interestingly, there are no true hornets (Vespa) native to North America. The European hornet (Vespa crabro) is well established in much of the eastern half of the United States. The European hornet is not a major threat to honey bees."
"Hornets are part of a large order of insects known as Hymenoptera that include bees, wasps, ants, and sawflies. Worldwide, there are more than 115,000 species belonging to the order Hymenoptera (Hunt and Toth 2017). Most of this group of insects are beneficial for pollination and pest control. There are two types of hornets, solitary and social (Lee et al. 2016). Solitary hornets hunt various insects and spiders. Their 'stinger' is primarily used to paralyze their prey. They often lay an egg on the immobilized victim, and when the egg hatches, the larvae consume the still-living host. Solitary wasps generally do not sting humans and usually are not aggressive unless provoked."
"Social wasps, on the other hand, do use their stingers to defend their nests and can be very aggressive and will readily sting. The most common social wasp in the United States is the yellowjacket. The four most common yellowjacket species in Washington are the western yellowjacket (Paravespula pensylvanica), the common yellowjacket (Paravespula vulgaris), the aerial yellowjacket (Dolichovespula arenaria), and the German yellowjacket (Paravespula germanica) (Berry and Mooney 1998; Landolt and Antonelli 2003)."
"The recently introduced Asian giant hornet (AGH) is also a social wasp. When foraging for food in spring, the AGH ;is not highly aggressive—unless its nest is disturbed. Late summer and fall, with the high demand for protein, they become very aggressive when attacking or occupying a honey bee colony."
AGH appeared in the news last month when the Washington State Department of Agriculture announced it had trapped aVespa mandarinia near Birch Bay in Whatcom County. It was trapped July 14 and 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," according to the news release.
"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," the news release related. "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. You can visit WSDA's website at agr.wa.gov/hornets to learn more about Asian giant hornets. You can also submit questions the WSDA Pest Program at hornets@agr.wa.gov or 1-800-443-6684."
At least we never saw a 64-point bold, all-capped, World War II-sized newspaper headline that screamed "MURDER HORNET TRAPPED!"
But some of the misidentifications of Vespa mandarinia flowing in are incredible. Check out Stephane de Greef's Facebook page on "Is This a Murder Hornet?" The latest one spotlighted is a...wait for it...beetle.
- Author: Kathy Keatley Garvey
Which one is the most popular? Initially, it was the tropical milkweed, A. curassavica. We collected the first five caterpillars there. The A. fascicularis yielded the rest.
So, the count: narrowleaf milkweed, 11; tropical, 5; and showy, a no-show.
To date this year, we have released six monarchs back into the garden. The others went for university research. Elizabeth Pringle's laboratory at the University of Nevada, Reno, needed male and female monarchs to rear a colony, and the UC Davis laboratory of Louie Yang needed some tachinid flies.
Unfortunately for us--and fortunately for the Yang lab--tachinid flies infested two of our "11-piece collection." The adult flies are parasitoids that lay their eggs in immature monarchs (among other hosts). The fly larvae hatch and eat their host from the inside out. In a chrysalid, you can tell a tachnid fly infestation by the large tell-tale "dented" brown spot, it looks somewhat like a rotten spot on an apple. In a caterpillar? Think withered and discolored. Then a bungee-like white string appears, and the larvae (maggots) slide down--probably gleefully--like a kid on a Goliath Slide at the county fair.
Tachinids, however, are considered beneficial insects. They lay their eggs in or on such pests as cabbage loopers, cutworms, cabbage worms, gypsy moths, hornworms, harlequin bugs, lygus bugs, cucumber beetles, earwigs and the like. (See Bug Squad blog for close-up images of the tachinid larvae and pupae.)
2016: A Very Good Monarch Year
The year 2016 was a very good year for monarchs in our pollinator garden; we reared and released 60-plus. Sadly, the numbers fell drastically in 2017, 2018 and 2019. Last year, no eggs, no caterpillars and no chrysalids, and only a few monarchs passed through. In fact, in 2019 we did not see our first monarch until Aug. 9.
This year we're noticing a comeback of sorts. We spotted the first monarch on May 24. We now see:
- Males patrolling our yard and chasing the females--morning, noon and evening
- Females laying their eggs on the narrowleaf milkweed that's beneath the honeysuckle vine or the tropical milkweed that's beneath the roses
- Both males and females nectaring on milkweed, butterfly bush (Buddleia davidii), and Mexican sunflower (Tithonia rotundifolia), napping in the branches of the cherry laurels, and greeting any guests with flutter fanfare.
Life is good.
Sometimes the Gulf Fritillaries, Agraulis vanillae, that are hanging out on their host plant, the passionflower vine, mistake them for one of their own species and a pursuit begins.
Yes, the predators are out there: the California scrub jays, praying mantids, spiders, European paper wasps and yellow jackets. So are the tachinid flies and parasitoid wasps.
Would it be too much to ask them to...um....leave our monarchs alone? Yes.
Everybody eats in the garden. The menu choice is theirs.
- 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).
More information:
- Visit the WSDA website at agr.wa.gov/hornets to learn more about Asian giant hornets.
- Submit questions to the WSDA Pest Program at hornets@agr.wa.gov or 1-800-443-6684.
- View the WSDA press conference on YouTube.
- Author: Kathy Keatley Garvey
No, they're not back, but they are in the news.
Or specifically, in a podcast.
Noted hymenopterist Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology, UC Davis Department of Entomology and Nematology, shed light on the giant insect in an interview 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.
Basically, two incidents occurred in North America last year. A single colony of the Asian giant hornet (AGH), Vespa mandarinia, 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. “There is no evidence that there are any more hornets in the vicinity of Vancouver or anywhere else on the West Coast," Kimsey told us in a BugSquad piece published on May 5.
Concerned beekeepers, however, worried that the hornets could become established and decimate their hives. Subsequently, entomologists from the Department of Agriculture and Washington State University urged folks to be on the alert and report any sightings.
Suddenly, citizens throughout the country reported seeing scores of "murder hornets," which turned out to be yellow jackets, European paper wasps, hover flies, hoverflies, moths and even a Jerusalem cricket (potato bug). Entomologists fielded all kinds of questions--and still are. Stephane De Greef, a Belgium-born entomology advocate, traveler, field guide, and photographer, called the frenzy "a bloody dumpster fire." He launched a fun (and informative) Facebook page, Is This a Murder Hornet?"
In the podcast, Kimsey relates that the Asian giant hornets are native to Asia, where the residents tolerate them. The beekeeping industry in Washington state, however, was "convinced that they are killing our honey bees," Kimsey told Bentley. "There's no basis in reality as far as I can tell," she said.
The Asian giant hornet is "one of about a dozen or so species in this genus," Kimsey said. She described them as "comically large and menacing looking."
The specimens in the Bohart Museum of Entomology are about 1.5 inches long. "I've never seen one two inches long. But it's a big animal--no question about it."
Bentley also discussed entomologist Justin Schmidt's Sting Pain Index, which rates the painful stings of some 83 hymenopteran species.
Kimsey agreed that the Asian giant hornet "can deliver a lot of venom" and "can sting repeatedly." But in her opinion, "the honey bee sting is the worst."
Other points Kimsey brought out included:
- The Asian giant hornets probably arrived here in cargo ships
- The larvae and pupae are restaurant-fare in some parts of Asia and are quite the delicacy
- The coronavirus pandemic has resulted in fewer cargo ships arriving in the United States from Asia, and thus fewer opportunities for hitchhikers.
Be sure to listen to the educational and entertaining podcast for the details. Or as NPMA wrote: "Where did the Asian giant hornet come from, has it become established in North America, and what threat could it pose to the U.S.? Get answers to these and many more questions in this episode featuring famed hymenopterist, Dr. Lynn Kimsey, as she dispels myths and rumors about this interesting insect."
Related Bug Squad blogs:
- About Those Asian Hornets (May 4, 2020)
- The Hornet Wars: 'A Bloody Dumpster Fire" (May 5, 2020)
- How Do You Say Murder Hornets? Delicious (May 8, 2020)
Matan Shelomi, former graduate student of Lynn Kimsey's and now an assistant professor of entomology at the National Taiwan University in Taipei, Taiwan, enjoys them. - Incredible Work, and Timely, on 22 Species of Hornets (May 12, 2020)
- Author: Kathy Keatley Garvey
The Western corn rootworm is called that because its larvae ravage America's corn crops to the economic tune of $1 billion a year.
Enter a team of nine researchers, including UC Davis biologist Scott Carroll. They analyzed data over a six-year period and concluded that crop rotation works well in battling the notorious pest that annually causes $800 million in yield loss and $200 million in treatment costs.
“Answering this question was important not only to grower success but the agricultural economy, said Carroll, an associate of the UC Davis Department of Entomology and Nematology and owner of the Davis-based Institute for Contemporary Evolution. “Bt crops are far-and-away the single most important factor reducing soil and crop insecticide applications in the United States at present.”
When Bacillus thuringiensis (Bt) corn was introduced in 2003, the pest seemed under control. The genetically engineered corn is a transgenic, insecticidal crop that kills rootworm larvae but is harmless to humans.
However, when the pest began developing resistance to the Bt corn toxins, the U.S. Department of Agriculture recommended crop rotation as a method of control. Crop rotation, an age-old agricultural tactic, is a consistent and economical means of controlling rootworms the season following an outbreak. It reduces rootworm densities, and is considered more effective than insecticides.
With crop rotation, “the frequency of problem fields declined by 92 percent in 2014 to 2016 relative to 2011 to 2013,” the nine-member team wrote in the research article, “Crop Rotation Mitigates Impacts of Corn Rootworm Resistance to Transgenic BT Corn,” in the current edition of the Proceedings of the National Academy of Sciences.
“Corn rootworm is one of the nation's most devastating pests, giving a sense of urgency to protecting the efficacy of industrial pest control approaches with reduced non-target effects,” said Carroll, who studies basic and applied aspects of evolutionary biology. “Transgenic insecticidal Bt crops in the United States are cultivated under a very interesting socio-evolutionary model of resistance management that is mandated by the U.S. Environmental Protection Agency. Individual growers must implement resistance management--usually by devoting a small acreage to planting a 'refuge' of non-Bt crops in order to nurture a local reservoir population of Bt-susceptible pest insects.”
Carroll pointed out that the “outstanding productivity of Bt corn has led a portion of growers to reduce or eliminate their required refuge planting. Moreover, many time-tested practices for integrated pest management have fallen by the wayside as growers have found they could rely solely on the genetics of the seemingly invulnerable Bt varieties.”
“As predicted, Bt resistance evolution in corn rootworm has accelerated. In response to this dire risk, in 2016 EPA began mandating crop rotation as a complementary means of reducing the damage to Bt corn fields caused by resistant corn rootworms. Our working group analyzed the success of this traditional agricultural tactic to help sustain the efficacy of the high-tech Bt tactic.”
Carroll said that under the leadership of his colleague Yves Carrière at the University of Arizona, “our team analyzed six years of field data from 25 crop reporting districts in Illinois, Iowa and Minnesota—three states facing some of the most severe rootworm damage to Bt cornfields.
“The answer we found is that traditional crop rotation is working to protect the Bt corn fields from rootworm damage, including in areas that have seen the evolution of behavioral resistance to crop-rotation by rootworms.”
The bottom line, said Carrière, is this: "Farmers have to diversify their Bt crops and rotate. Diversify the landscape and the use of pest control methods. No one technology is the silver bullet.”
The project also included scientists from North Carolina State and McGill University, along with Carroll's colleague, Peter Jørgensen of the Stockholm Resistance Center.
While Jorgensen was pursuing his master's degree program at the University of Copenhagen and studying at UC Davis, he worked with Carroll and Sharon Strauss of the Department of Evolution and Ecology.
“This PNAS paper,” Carroll said, “is one of several that have developed from a pursuit Peter and I organized on 'Living with Resistance' at the National Socio-Environmental Synthesis Center in Annapolis, with the aim to explore more sustainable approaches to managing evolutionary challenges to health and food security.”
The abstract:
"Transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt) can suppress pests and reduce insecticide sprays, but their efficacy is reduced when pests evolve resistance. Although farmers plant refuges of non-Bt host plants to delay pest resistance, this tactic has not been sufficient against the western corn rootworm, Diabrotica virgifera virgifera. In the United States, some populations of this devastating pest have rapidly evolved practical resistance to Cry3 toxins and Cry34/35Ab, the only Bt toxins in commercially available corn that kill rootworms. Here, we analyzed data from 2011 to 2016 on Bt corn fields producing Cry3Bb alone that were severely damaged by this pest in 25 crop reporting districts of Illinois, Iowa, and Minnesota. The annual mean frequency of these problem fields was 29 fields (range 7 to 70) per million acres of Cry3Bb corn in 2011 to 2013, with a cost of $163 to $227 per damaged acre. The frequency of problem fields declined by 92% in 2014 to 2016 relative to 2011 to 2013 and was negatively associated with rotation of corn with soybean. The effectiveness of corn rotation for mitigating Bt resistance problems did not differ significantly between crop-reporting districts with versus without prevalent rotation-resistant rootworm populations. In some analyses, the frequency of problem fields was positively associated with planting of Cry3 corn and negatively associated with planting of Bt corn producing both a Cry3 toxin and Cry34/35Ab. The results highlight the central role of crop rotation for mitigating impacts of D. v. virgifera resistance to Bt corn."
