How should we react to the arrival of the "murder hornet?"

How should we react to the arrival of the "murder hornet?"

They can grow to be about two inches in length. Their stings have been likened to “having red-hot thumbtacks being driven into [the] flesh.” Their stingers are long enough to pierce the standard beekeeping suit. And, they’ve just arrived in the United States.

Does the region have to worry about the Asian giant hornet? We talk to our favorite bug expert, Mike Raupp, about the origins of the murder hornet, their environmental benefits and how we should react to their arrival.

Produced by Richard Cunningham


  • Michael Raupp "Bug Guy" and Professor of Entomology, University of Maryland; @BugoftheWeek


  • 12:00:04

    KOJO NNAMDIYou're tuned in to "The Kojo Nnamdi Show" on WAMU 88.5. I'm broadcasting from home, so welcome. Later in the broadcast, we'll be joined by Joe Galloway to talk about his latest book "They Were Soldiers," along with three veterans who will share how their experiences in Vietnam have shaped their lives. But first, the Asian giant hornet, known commonly as the murder hornet, was found in Washington State earlier this month. They can grow up to two inches long, and their stingers are long enough to pierce through the standard beekeeping suit. The bugs have received a lot of attention on social media. But they do they warrant all of the hysteria? How did these hornets reach the United States? And how panicked should we be about them in this region? Joining us now is Michael Raupp. He's a Professor of Entomology at the University of Maryland, also known as the "Bug Guy." Michael Raupp, welcome. Thank you for joining us.

  • 12:00:54

    MICHAEL RAUPPKojo, it's delightful to be with you today. This is going to be one crazy ride here this morning, I think, or this afternoon.

  • 12:01:04

    NNAMDIWell, first things first. What's most important is that I am not seeing you right now, and I've always seen you when we talking together. So, happy birthday.

  • 12:01:14

    RAUPPWell, Kojo, thank you so much. And, you know, what could be better than to share my birthday with Kojo and all the folks here in the DMV? Now, Kojo, I don't want this to sound too much like a bromance, but I always enjoy being on the show. And I do miss you.

  • 12:01:32

    NNAMDIAnd you did share a birthday with me, my birthday with me on this show one year.

  • 12:01:36

    RAUPPYes, we did.

  • 12:01:36

    NNAMDIOnto the issue. Why are they called murder hornets?

  • 12:01:39

    RAUPPOkay. Well, murder hornets is a bit of a misnomer. I think more correctly they should called slaughter hornets. Well, this is a little more friendly than murder, maybe slaughter. I don't know. But, fundamentally, what here is there was a Japanese scientist that studied in great detail the life history of these particular insects. And what he found is they have this very bizarre behavior. It's very unique. These are specialists on our social bees. In other words, things like honeybees. Now, normally, these wasps and many wasps and hornets -- hornets are simply a large social wasp -- their typical behavior is to go out and hunt prey. And those prey can be things like caterpillars or beetles on our plants. So, in some regard, they're enormously beneficial. These particular ones, these Asian giants have a very different behavior.

  • 12:02:39

    RAUPPAt first, they will start to hunt honeybees, pick them off. What they do is they chew them into a meatball. They take them home and feed their babies back in their nest. With the Asian giant, what will happen in the autumn, particularly, is they will switch from a hunting phase into what the scientists call the slaughter phase. And during the slaughter phase, they will find a bee colony, focus their attention on a single beehive. And as the honeybee soldiers come out to defend their nest, the giant Asian hornets will decapitate them and throw their corpses down in front of the hive, on the ground. In other words, they're not chewing them up and taking them back to feed the babies. They are simply slaughtering those bee defenders.

  • 12:03:35

    RAUPPOnce they've killed the defenders, they will then enter what we call the occupation phase, where they enter the beehive. They will post guards at the entry, and if any animal or a human being should come, those wasp hornet defenders will come and drive an invader away. The other hornets will then proceed to rob all the larvae and the brood of the honeybees, capture them, turn them into meatballs, fly them back to the hornet colony to feed their brood. And scientists have found that 20 to 30 of these hornets can eliminate 25,000 honeybees in the span of about three to four hours. So, this is incredibly problematic for beekeepers. And I think that's where they get the name murder hornets, because of this very unusual behavior, this slaughter phase of the attack.

  • 12:04:37

    NNAMDIWhat threat do they pose to humans, Mike?

  • 12:04:40

    RAUPPWell, you know, to humans, this is no joke. Again, understand that anytime we have a foreign protein introduced into the human body, we can have an allergic reaction. Many of us have simple allergies to cat dander to things like pollen. But, in certain cases -- and particularly with these wasps, hornets and bees that have venom -- that can cause a severe allergic reaction, which, of course, we call anaphylaxis. Anaphylaxis, in and above itself, can be a life threatening situation to someone that has that severe allergic reaction. But beyond that, the venom of the Asian giant hornet, it actually turns out to be only about half as toxic as honeybee venom. But by virtue of their very, very large size, they're delivering a very large dose.

  • 12:05:43

    RAUPPAnd there are records now coming from Asia where people who are stung several times by several of these hornets can find they actually will be intoxicated and have very severe reactions, and may be actually killed beyond that anaphylaxis phenomenon. That venom is a variable witch's brew of toxicants. It contains what we call a cytolytic venom. What that does is it breaks down tissue, cell membranes. And it also contains a neurotoxin that can affect organ function and muscle function. So, this is kind of a double whammy, and this is the threat they pose to humans.

  • 12:06:32

    NNAMDIMike, it is the Asian giant hornet. How did they get to the U.S.?

  • 12:06:37

    RAUPPGood question, Kojo. I think we have to understand, in every single day here in the United States, there are literally thousands and thousands of containers that enter our ports. A very insignificant number, a tiny number of those containers are actually inspected before they leave that country and arrive at our shore. So, much the same way, we had the emerald ash borer show up here in the late 1990s. The brown marmorated stink bug, one we visited with several times, and everybody hates that stinky guy. Hey, that showed up in Allentown, Pennsylvania in the mid-'90s as well. We think these things are probably coming in with containerships. I'm guessing that it was a simple matter of a containership porting perhaps in SeaTac or somewhere in the Pacific Northwest. Somebody opened up a container, and there inside was an impregnated Asian giant hornet.

  • 12:07:40

    RAUPPIt will only take one of these queen hornets that's been impregnated to be able to found and establish a new colony once they hit the shore. So, I believe this is how that particular hornet arrived, was through global transit of goods.

  • 12:08:00

    NNAMDIMike Raupp, what should we do? Are they a threat to us here in the Washington region?

  • 12:08:07

    RAUPPWell, Kojo, there's some good news in all this. And I want to talk briefly about invasion biology. What we know historically, this is called Williamson's Rule of Tens, that of new creatures, new invasive species that might arrive at our shores, it's a very insignificant portion that can actually survive and establish populations. We think it's about 10 percent of newcomers actually can get a toehold. And of that 10 percent, it's only about 10 percent of that that actually will become pests. So, now let's backtrack to 2019, to Vancouver Island, when they actually found a nest in September of these Asian giant hornets and they exterminated that nest.

  • 12:08:57

    RAUPPSince that point in time, there have been a couple of other detections. Again, about 10 to 15 miles south, right across the U.S. border in Washington State, apparently some beekeepers found their hives had been raided, and that's a sure signature. Hey, when you see hundreds or thousands of dead decapitated honeybees in front of your hive that's a pretty good clue that you have the Asian giant hornet. So, again, right now we know we've had one established colony. We've had other detections in Washington State. Now, the bad news, here, Kojo, is genetic trace-backs would indicate that those two distinct discoveries, the one in British Columbia and the one in Washington State, that the hornets they found were genetically distinct.

  • 12:09:54

    RAUPPWhat this implies is there may have actually been two introductions, two unique introductions. So, let's talk about the theory, now. So, in theory, in theory, we could have a ship arrived at Port of Baltimore, Norfolk. We could have a container in there with a queen who will make it out, who might establish, worst case scenario. But we also know that it takes a very long time for these particular invaders, once they establish, to actually spread. With the Asian giant hornet, it forages only about one to two kilometers a year, maybe as much as eight. So, if we run the math on this, that initial introduction 3,000 miles away is going to take certainly years or even decades to hit the East Coast and the DMV. Hey, it took brown marmorated stink bug more than a decade to go from Allentown, Pennsylvania to California.

  • 12:10:53

    RAUPPSo, we've got time. This is not something that we have to panic about right now here in the DMV.

  • 12:11:01

    NNAMDIHere is Kathy in Falls Church. Kathy, you're on the air. Go ahead, please.

  • 12:11:07

    KATHYThank you for taking my call. I'm actually calling to ask about if there's something someone can do who keeps bees, you know, in their yard. My brother does in Massachusetts. I don't. But I'm really more asking for him. Is there anything to do to prevent an infestation of these hornets? Thank you.

  • 12:11:25


  • 12:11:26

    RAUPPAbsolutely, Kathy. And before I go there, I just want to give a real shout-out to the dozens of viewers and listeners that have sent me images and descriptions of hornets they found in and around their homes over the past two weeks. By the way, all of these have turned out to be European hornets. That's an entirely different kettle of fish, here. So, we're not going to worry about that. But to address your point Kathy, absolutely. What your beekeeper, again, brother should be doing, and what all our commercial beekeepers should be doing right now is going to the websites, including my "But of the Week" website. I'm going to put in a shameful plug here for "Bug of the Week," Kojo, I apologize for that. But this is going to save me some time down the road. Go to those websites. Washington State University and Washington State Department of Agriculture have wonderful resources.

  • 12:12:24

    RAUPPSee what this thing looks like so you can recognize it. Learn what an attack looks like, so if you're beehives are attacked, you will be able to recognize. It's not time to panic. It's time to become educated. So, I urge everyone, beekeepers and citizens, to visit these educational websites. Calm your fears. But to learn what to look for.

  • 12:12:49

    NNAMDIHere's Tony, who identifies as President of D.C. Beekeepers. Tony, you're on the air. Go ahead, please.

  • 12:12:55

    TONYHey, there. I just wanted to respond to your request for local beekeeper opinion about how concerned we are directly about this. And the answer is, we're really not. We are far more concerned by the level of fear that it has aroused in our neighbors. Both beekeepers and the government officials we work with are being besieged with pictures of even bumblebees that people have found and killed, because they don't know what insects look like. And now they're basically afraid of everything. The way in which this has been talked about has really, to my mind, only served to damage the insect world and not make beekeeping safer. I have had people contact me and say they don't want to even think about becoming a beekeeper in a world with this hornet in it. And I think that's just extremely unfortunate.

  • 12:13:47

    NNAMDIMike Raupp?

  • 12:13:49

    RAUPPYeah. I totally agree with Tony, here. I mean, you know, frankly the moniker murder hornet, it sells newspapers. But, again, understand that this is simply another insect basically learning what Mother Nature's opportunities have presented in doing this. We have beekeepers, certainly, in invaded -- in the natural range throughout Asia. There are more than 10 nations where this insect is known. And beekeepers are just rolling along over there, just as they should and just as they will. Certainly, the important thing now I think to your point, Tony...

  • 12:14:35

    NNAMDIOnly got about 20 seconds left, Mike.

  • 12:14:36

    RAUPPOkay. The important piece here, again, is to become educated to learn what it looks like, but to put your fears at rest. Okay. It's not here. It would take a long time, but it's time to get educated.

  • 12:14:49

    NNAMDIMichael Raupp is a Professor of Entomology at the University of Maryland known as the "Bug Guy." Christine tweeted, "Great episode. My eight-year-old is obsessed with these hornets. Now I don't have to make up answers to all of her murder hornet questions." Mike Raupp, thank you so much for joining us. We're going to take short break. I'm Kojo Nnamdi.

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