Hymenopterist Lynn Kimsey, director of the Bohart Museum of Entomology, with a Asian giant hornet specimen from the Bohart collection

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)

Have are you faring during the COVID-19 crisis?

If you have a pollinator garden--or access to you--and a camera, you can step out of The Great Indoors and enjoy The Great Outdoors.

A newly eclosed Western Tiger Swallowtail, Papilio rutulus, however, can take your breath away.

This one recently visited our butterfly bush, Buddleia davidii, in our pollinator garden. It fluttered across the garden and headed straight toward one bush: the aptly named butterfly bush. 

Wikipedia tells us: "The genus is found in four continents. Over 60 species are native through the New World from the southern United States south to Chile, while many other species are found in the Old World, in Africa, and parts of Asia, but all are absent as natives from Europe and Australasia. The species are divided into three groups based on their floral type: those in the New World are mostly dioecious (occasionally hermaphrodite or trioecious), while those in the Old World are exclusively hermaphrodite with perfect flowers."

There's a movement afoot NOT to plant Buddleia davidii (see the North American Butterfly Association's "The Great Butterfly Bush Debate"), but we've had ours for a decade, we keep it under control, and we love it for its beauty, its aroma, and its ability to draw a wide variety of insects. 

Insects love it, too. 

Close-up of moth specimen preparation. (Photo by Kathy Keatley Garvey)

Are you counting down until the much-awaited Virtual Moth Open House, hosted by the UC Davis Bohart Museum of Entomology?

The free and family friendly-event is set from 1 to 2 p.m.,  on Saturday, July 25, coming to you live on the Bohart Museum's Facebook page. You don't have to have a Facebook account to watch the program.

Entomologist Jeff Smith, who curates the Bohart's Lepidoptera (moths and butterflies) collection, will display moths, talk about moths and answer your questions.

And it's all in keeping with National Moth Week.

Curious as to how he pins and spreads the moth and butterfly specimens? Be sure to check out Sarah Stinson's newly recorded video in which Smith demonstrates how to Pin and Spread Moths and Butterflies. The link is on the Bohart Museum's home page.

"I've been managing the butterfly moth collection for the last 32 years," he says. "And much of what I do has to do with spreading the wings of butterflies and moths so that they're ready and available to be identified."

You'll learn about spreading boards, pins, forceps, and yes, why you should use kitty litter. And you'll learn why you should keep "little bugs" away from your specimens  "before you get around to working on them."

"I've done these spreading demonstrations for many, many groups including the (UC Davis) entomology club," he relates. "And as I tell them as I start, I'm going to show you how simple this is. But the first time you do it, you're going to be very, very frustrated."

Smith, who was singled out for the prestigious Friend of the College Award in 2015 by the UC Davis College of Agricultural and Environmental Sciences, is in one word: "incredible."  (See news story)

He makes it look easy. It's not. 

"Personally, I am astounded by the thousands upon thousands of butterflies and moths that Jeff has prepared for display or scientific study," research entomologist Tom Zavorink, a Bohart Museum associate, told us. "This is no small task because butterfly and moth specimens are usually brought from the field in envelopes or boxes with their wings folded over their backs or around their bodies, and preparing them for display or scientific study involves relaxing them in a humid chamber so their wings and legs can be manipulated, carefully spreading open the wings, positioning them on a flat surface, and securing them in that position until the specimen dries again. This is an onerous task that many entomologists, myself included, shun because we don't have the time, manual dexterity, or patience it takes to prepare quality specimens."

At the Virtual Moth Open House, there's an extra bonus: learn how to set up a blacklighting trap to collect night-flying insects. (See previous Bug Squad blog)

The Bohart Museum is directed by Lynn Kimsey, professor of entomology at UC Davis, and is located in Room 1124 of the Academic Surge Building on Crocker Lane, UC Davis campus. It houses nearly 8 million insect specimens, and about 500,000 of them are butterflies and moths. The museum also houses a live petting zoo (Madagascar hissing cockroaches, stick insects and tarantulas) and an insect-themed gift shop, stocked with T-shirts,jewelry, books, stuffed animals, posters and insect-collecting equipment. Due to the coronavirus pandemic, however, the museum is temporarily closed until further notice.

Biologist Scott Carroll (Photo by Jenella Loye)

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."