The (Not) Invasion of the Asian Giant Hornet

We Can Stop Panicking about Murder Hornets

The (Not) Invasion of the Asian Giant Hornet

When you hear a term such as “murder hornet” naturally you will be intrigued and wary. The Asian Giant Hornet is taking over headlines recently with a lot of fear and even misleading information. Please allow us to dispel a few myths and help calm nerves of beekeepers across the United States. Granted, these Asian Giant Hornets are large, scary-looking, and pack a pretty bad sting. They aren’t something to discount if you are face-to-face with one. However, the odds of you coming in contact with the infamous “murder hornet,” Vespa mandarinia, are incredibly low.

Vespa mandarinia, or Asian Giant Hornet

A few confirmed specimens of the Vespa mandarinia were found in Northwestern Washington, very near the border with Canada in late 2019. A few months earlier, a nest of Vespa mandarinia was found and destroyed in British Columbia, just a few miles north of the border with the U.S. Now, the thoughts of a nest are worrisome and make you want to think that if there is one nest, then there must be multiple. Perhaps, but even though people are actively looking, no more have been found. You see, these particular hornets have a very specific way of reproducing. A queen is typically mated very early in her lifespan but then hibernates through the winter with her fertilized eggs inside of her. In the early spring, she emerges, begins a nest, and raises her first workers from her eggs. Once they are mature, she can spend much more time laying eggs as they take over the care of the larvae. It isn’t until late summer to fall that she begins laying eggs that will become either males or queens. This is also near the end of her lifespan. It is only the new queens that will survive the winter to build new nests.

Cicada killer, may be confused with AGH

The nest in British Columbia was found and destroyed in September, so it is very likely that no new queens could have hatched and reached a viable stage before the nest was destroyed. Also, these are such a conspicuous insect; it is highly unlikely that they would go unnoticed for long. Sloan Tomlinson, an entomologist known as “The Wasp Guy,” says,

“Given that last summer was the first ever sighting of these wasps, I would believe that there was likely a queen that came over on a shipment, perhaps even one that came over in winter, meaning she would have been in torpor and when warm weather came she left, found the burrow in Nanaimo, and built her nest. Even if they did establish, these are large wasps that need huge amounts of protein to feed their larvae and eventually produce new queens. It would be difficult for them to establish in a manner that would allow their populations to grow to a level where they would become a serious threat to the beekeepers of the nation. They would be found and destroyed.”

Sloan Tomlinson

Washington State Department of Agriculture has asked for the help of beekeepers in the Northwestern Washington area, specifically Whatcom County to be on the lookout for more possible Asian Giant Hornets. They have even specified how to create a trap using a clear jug and fresh orange juice mixed in equal parts with rice wine. While this will be helpful in case of the possibility of there being more of these Asian Giant Hornets, beekeepers outside of this area do not need to participate in setting traps. In fact, it may be quite detrimental to your local native pollinator populations to do so. According to Tomlinson, “The alcohol mixed with orange juice causes the sugars in the juice [to] amplify their scent, making them highly attractive to any insect seeking a heavy nectar meal. Also, know that the traps will have a lot of bycatch. The traps will kill a wide variety of nectar-feeding insects from bees to wasps, to ants and beetles. Since the WSDR isn’t really caring about that fact, if you do put up a trap it would be helpful to [identify] bycatch and give that info for entomologists to help assess native nectar feeder populations, instead of just throwing it away.” Apparently, the rice wine will not deter the beneficial bees from being drowned in the trap, and many native species will be killed as well.

European hornet (Vespa crabro) is about 1 inch long, they are also an invasive species

The killing of native species is another concern among entomologists with the fear being caused concerning the Asian Giant Hornets. They are seeing a large rise in people asking if a certain insect (usually already dead) was one of the “murder hornets.” These have included many beneficial insects such as bumblebees and cicada killers that also happen to be larger. Asian Giant Hornets are much larger than most of these other insects. The workers are typically 1.5-2 inches in length. Queens can be up to 2.16 inches. That is about the size of your thumb. They also have a very distinctive yellow-orange head that is disproportionately large to their body compared with most other wasp species.

Bald-faced Hornet, Much smaller than the AGH.

While Vespa mandarinia is a threat to honeybee populations, they may not quite be the threat to humans that some reports are making them out to be. With fear-inducing reports of up to 50 people in Japan being killed each year by the Asian Giant Hornet, remember that people also die here of bee, wasp, and hornet stings. The Asian Giant Hornet typically only attacks humans when they feel that their nest (usually well-hidden underground) is threatened.

Image courtesy of the Washington State Department of Agriculture.

Scientists and entomologists are working very hard to make sure that the Asian Giant Hornet does not establish itself in North America. There is no evidence to suggest that it has. With the exception of beekeepers in the very northwestern part of Washington State, there is nothing we can do to help combat the possibility of “murder hornets” in the United States. So please stop killing every large flying insect that you see.

What North American insects look like the Asian Giant Hornet? Click here for a list!

Resources

Asian Giant Hornet. (n.d.). Retrieved May 6, 2020, from Washington Department of Agriculture

Asian Giant Hornet with WSDA’s Sven-Erik Spichiger (S2,E23). (2020, April 3). Retrieved May 4, 2020, from Beekeeping Today Podcast

Fox, A. (2020, May 5). Smart News-No, Americans Do Not Need to Panic About ‘Murder Hornets’. Retrieved May 5, 2020, from Smithsonian Magazine

Tomlinson, S. (2020, May 4). (R. Sanderson, Interviewer)

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