Vespid-19: the Asian giant hornet in North America

How I wish I could claim credit for the phrase Vespid-19. But, alas, I cannot. It was suggested to me by Nancy Partlow of OlyPollinators and it perfectly describes the current situation. An exotic vespid wasp, Vespa mandarinia, was first discovered in the Pacific Northwest in late 2019 and has since spread further and faster than originally anticipated. The phrase and the events bear a certain familiarity, no?

But there it ends. Although I wrote about these creatures briefly last fall, I wanted to spend a few minutes trying to restore reason and good judgment into the narrative.

What is murder?

Let’s start with the nickname “murder hornet.” Murder is a human word for a human deed. The word implies evil-doing with premeditation. Since murder is something to be reviled, the word raises fear.

But wait! The Asian giant hornet is just a bug. And when it kills things—or entire hives of things—it’s just doing what good moms do: providing for its young. Feeding the young is exceptionally common in the animal kingdom. Birds do it, mammals do it, and even bugs do it.  Even though moms of social animals like wasps and honey bees have help in the form of non-reproductive workers, it amounts to the same thing. Those marauding hornets are just tripping to the local food bank for supplies.

Doing the most damage

So when I read that people all over the country were stocking up on insecticide to protect themselves from a pest they will probably never see in their entire lives, I began to worry. How many innocent bugs will die in the process? And how many vitally important pollinators? Who can do more damage, Asian giant hornets or humans armed with cans of bug spray?

One report said people were confusing cicada killers, European hornets, yellowjackets, and even bumble bees with Asian giant hornets. Bumble bees? Can you imagine spraying bumble bees to save your honey bees from hornets? How is that a win for pollinators?

What many people don’t realize is that bees, wasps, and hornets are all closely related. Any pesticide that kills one will most likely kill the others, so there is no easy way to exterminate just one in the group. Separating the species is usually done in more complex ways, such as mechanical trapping or using scent lures that are attractive to certain species.

Fearing the obscure

In addition, fear of the hornets is totally out of line. So far this year, one Asian giant hornet has been found near Custer, Washington and another in Langley, B.C. Yes, this is a greater spread than entomologists predicted for the first year, but the numbers are extremely low. Although others will certainly be found, the incidence is not high enough to warrant killing everything that flies.

Beekeepers have a greater risk of hornet problems than others, yet most of the panicked public are not beekeepers but people who fear getting stung. Yes, the hornet is capable of inflicting a powerful sting, but they are not out to “murder” humans or their pets. In fact, you have no idea how uninteresting you are.

To a hornet, you are simply an impediment, something to be dealt with like a roadblock. The easiest thing for them to do is avoid you—fly around—which they will do if you leave them alone. Your biggest risk of stings comes from annoying or interfering with them. But if you never see one in your entire life—which is likely—you have an extremely small chance of getting stung by one.

Save the pollinators

I go back to the same thing every time. If you want to save the bees, plant flowers, conserve pollinator habitat, and eschew the poisons and ‘cides. As far as Asian giant hornets are concerned, report them if you see them but otherwise leave them alone.

Honey Bee Suite

The Asian giant hornet. Photo taken by chapeng and posted to iNaturalist.
The Asian giant hornet. Photo taken by chapeng and posted to iNaturalist.


    • Liz,

      Indeed they do. That’s about the same number of deaths we have in the US from honey bees each year. Perhaps we should get rid of all of them?

  • This was my submission beginning of May to the Washington State Department of Agriculture, Comments and Questions:

    No response yet. Does it make sense?

    Asian Giant Hornets, from the NYT:

    “… Scientists have since embarked on a full-scale hunt for the hornets, worried that the invaders could decimate bee populations in the United States and establish such a deep presence that all hope for eradication could be lost …”

    Being a beekeeper myself I was aware of research going on in NZ whereby 6,000 bees were equipped with RFID chips. My suggestion 3 or 4 years ago, when these hornets were first spotted in France and the Southern UK, was to catch and equip a hornet with a RFID chip which I thought would lead to the hornet’s nest. What I did not understand back then is that these chips were “passive”, only collecting data but in need of an external reading device.

    Maybe technology has advanced to have chips small enough to be mounted on hornets that collect data and transmit them.

    Alternatively, a drone capable of carrying heavier equipment can follow the hornet in a safe distance and read the RFID Chip in real-time and transmit it back. Once a nest has been identified it can be destroyed. In the UK they apparently used flamethrowers something you may not want to during fire season. Liquid CO2 may be as effective with fewer “side effects”.

    I read that in China they attach a silk thread to a hornet and follow it to the nest. So my idea may not be as novel just higher tech. If applied w/o delay and coordinated with Canada the hornet may well be eradicated.

    While most domestic bee species limit their range to a few hundred metres or one kilometre around their nest honey bees have been reported to fly distances in excess of 12 km if need be. What is the range of these hornets?

    I would appreciate your thoughts,

    Dr. Dieter Remppel, Canmore, AB. CDN

    • Dieter,

      It makes sense to me, but I think the biggest deterrent would be cost. Our state in particular seems to be cash-strapped, as are many others, so where would the money come from? And how would we determine the cost/benefit ratio?

  • There does not appear to be any spread at all this year. We are told genetic analysis of the Nanaimo nest that was destroyed and the specimen caught in Blaine/White Rock last year were unrelated and were from separate introductions.

    That means the specimens collected this year in Custer and Langley are probably from either that nest last year near Blaine/White Rock (they may be unmated queens of that colony, now at the end of their lifetime, analysis is in progress). Or possibly they are from daughter queens of that 2019 nest who have now established their own colonies in 2020. Either way, they have not gone far at all.

  • Good article to remind people to be cautious w/pesticides. Over Memorial weekend some idiot sprayed somewhere around us and four beehives of mine were just devastated by losses. For four days now they have been dying and bringing out the dead. Now we have to worry if they stored or fed any pesticide to the larvae for another loss when they start emerging. I wish people were not so dimwitted and full of fear and panic when it comes to insects. They do such great things for the world, yet they are decimated by humans. Thanks again for the article Rusty. It’s up to beekeepers to educate the public in the right ways and not create such panic with regard to one little insect.

  • Pure hysteria…something modern humans thrive on. The beekeeping establishment has said that the European hornets that are in abundance here in Maryland would decimate hives, they don’t. I am watching Euro hornet queens flying all around my bee yards this time of year. Later in the season, from experience during past years, I have seen these rather large hornets attempt to enter our colonies, only to be picked apart, balled, and cooked by fierce honeybees. I have even found them mummified by layers of propolis inside colonies. My bet is that Asian hornets will get a foothold due to our careless globalization behavior, but our bees will meet their intrusion with fierce opposition. Japanese honeybees have this very same trait and often keep Asian hornets at bay. Certainly a handful of bees will be picked off, but overall honeybees still thrive in Japan and other Asian countries just fine despite the presence of hornets.

  • When Asian hornets were first seen in the UK all beekeepers were urged ,and still are, to putt out hornet traps. Of course I did too in the first year but all I caught were various pollinators and European hornets. I decided this was not right ,why should I kill all these innocent critters in order to trap something that will probably never come near my apiary in 1m years? I’ve never used them since.

  • I think it’s a mistake to be cavalier about Vespa mandarinia or Vespa velutina or mistake the two for each other as I have seen done in some news commentary. The introduced Eurasian wasps/hornets and our own honey bees dominate already and they, in turn, are dominated by the above two species. I can see the eventuality of dealing with the 2 new introductions being a challenge for commercial beekeepers.

  • Rusty,

    I’m glad you wrote this article to clarify this for everyone. You prompted me to ask your opinion about a European hornet nest I am contemplating the outcome for. The queen is building a house inside one of my swarm traps that is in storage in an open barn area. I check on the nest every so often and it’s right now about the size of an orange. I can see capped brood and large larvae inside the nest when I flip over the lid on the swarm trap.

    I’ve done some research using credible sources on European hornets and I know that’s what she is. However, the resources are vague about how good or bad European hornets are for the environment and for honey bees. The consensus seems to be that European hornets eat a lot of flies and other less desirable bugs and will occasionally prey on a weak honey bee hive especially in late summer when they are raising brood. I do have about 17 hives within about a mile of this European hornet nest. This European hornet nest is not bothering me and is not in a heavily accessed area of my farm so it can stay. Or I can crush it…

    What do you know of this and what would you do? 🙂

    Theresa Martin

    • Well, I’m inclined to let things live if there’s a choice, and I also agree that the European hornets are only incidental predators on honey bees, so I don’t see a problem with leaving it.

      • I’m new to this site, but I’m familiar with a German website on hornets. This may seem like a crazy question, but could European hornets and bald-faced wasps paradoxically be protecting bees by preying on yellowjackets? According to vespa-crabro.de some beekeepers will actually encourage hornets to build nests because they prey on wax moths.

        • Robert,

          Well, each place has a different set of predators, so perhaps that would work in some places. Here, I see bald-faced hornets picking off honey bees even faster than the yellowjackets do.

  • Looks like a worker was found in Whatcom county, there’s a news release below:


    Hopefully, they find the nest for this one and the others that are probably out there before they become established. I guess we’ll know in the next couple of months as the queens from last year’s nest are probably established in their nest by now and producing workers. I listened to the news conference link they had and apparently a reproducing nest will kick out around 200 or so queens at the end of the year. I’m guessing only a tiny fraction get established but it looks like at least one and likely more are established. There’s some cool technology they are using involving rf id tags and GPS tags and beelining that they are planning to do, some of which has already been used to deal with the Asian hornet, although unsuccessfully in mainland Europe. I understand those hornets are tree nesters and give off a good signal whereas the Asian giants are ground nesters so they will need to capture the position before they head underground.

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