The Asian Giant Hornet, nicknamed the ‘Murder Hornet’ is the largest hornet in the world. Vespa mandarinia, the scientific name for Murder Hornets, average between 1.5 inches to 2 inches in length. By comparison, honeybees are about 0.5 inches long.
They have a huge yellow-orange face, like something out of a monster cartoon, according to Susan Cobey, a bee breeder at Washington State University’s Department of Entomology.
Their eyes look like a leading quote mark (‘), giving their face their signature strange appearance. They have a yellow-and-black banded thorax, similar to a yellow jacket in the related genera Vespula, although their yellow is darker, almost orange.
Most of what we know about their social habits and biology comes from observations in Japan (based on Matsuura, 1984, 1988; Matsuura and Sakagami, 1973).
They are aggressive social hornets. Each colony is composed of a reproducing queen and numerous workers. In the early stages of the colony, from about late April to early July, the queen does all the work of foraging, building the nest, and caring for the young.
As the sterile workers mature, the queen retreats to the nest and doesn’t venture out anymore. The workers can fly up to two kilometres from the nest to forage, looking for oak sap and similar nectar to feed the colony.
Around September or October, the males are born and new queens are born in late October and November. Once one of the males mates with a queen, the colony dies off and the new queen(s) flies off to find a suitable site to overwinter.
The next spring, the queen will emerge to begin the cycle all over again.
The queen typically builds her nest underground, utilizing old gopher or mouse holes, although occasionally some will build inside hollow logs. Aerial nests are rare and the only three ever observed were in man-made structures (Matsuura and Sakagami, 1973).
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Where Do Murder Hornets Come From?
As the name indicates, Asian Giant Hornets are native to Asia. They are found in Bhutan, China, Japan, Korea, Laos, Malaysia, Myanmar, the lowlands of Nepal, Taiwan, and Thailand. They usually inhabit regions below 4,500 feet in altitude.
Temperate and tropical forests are their normal habitat. They feed on tree sap from oaks, elms, and similar trees. They also chew on the wood to gather material for building their underground nests. In Japan, the hornets are often harvested for food and medicine.
The larvae and pupae are gathered by hornet hunters then prepared in much the same way as seafood and other rare meats (Nakamura and Sonthichai, 2004). In Japan, they are considered a seasonal delicacy.
As late as 2008, nests containing larvae and pupae sold for as much as $100/kilogram in Japan, China, Thailand, and elsewhere in Asia, thus providing a source of income for poor villagers who were willing to risk harvesting them.
Are Murder Hornets In The US?
In a word, yes. The first confirmed sighting was in Blaine, Washington in December 2019. It was the third sighting in North America. Other specimens were discovered in Nanaimo and White Rock, British Columbia in Canada early that year.
Foreign species of insects often arrive in America on shipping crates, in potting soil, or large potted plants where a queen might be overwintering during the journey. Once in the United States, the queen emerges and flies off to begin starting a new colony.
This is unfortunate because there aren’t any natural predators for them here, allowing them to spread without limit if they begin reproducing before researchers can find and eradicate the existing nests.
Since each colony only has one reproductive queen at a time, if a hive can be found and the queen eliminated before more queens are born in November, their spread can be stopped.
Are Murder Hornets Deadly?
Asian Giant Hornets acquired the nickname ‘Murder Hornets’ because of their unsavory habit of slaughtering honeybees to feast on the young for protein during the October/November time frame when males and new queens are maturing.
This phase of their life cycle is known as the “Slaughter and Occupation” phase (Matsuura and Sakagami, 1973). A foraging worker will discover honeybee hives and leave a pheromone marker to alert others in the hive to their location.
The workers will gather nearby until 50 or more have arrived, then attack in a mass slaughter. Using their tremendous size and strength to their advantage, they will decapitate the adult honeybee population, slaughtering thousands of them at a time.
They’ll leave huge piles of dead bees on the ground outside the honeybee hives
The attack can take place over a period of several hours. Once all of the adult honeybees are dead, the murder hornets will occupy the conquered hive and feast on the developing larvae. They will also defend it against Vespa mandarinia from other hives.
Despite anything you may hear from CNN, the New York Times, or any other media group, their nickname comes exclusively from this slaughter and occupation phase of their life cycle, not from any danger they present to human beings.
However, in Asia, Japanese honeybees have developed a method of combating their larger, stronger enemy. Asian Giant Hornets will die from heat in about 20 minutes or so when the temperature rises above 111ºF degrees.
The Japanese honeybees can survive until the temperature reaches 122ºF. They will surround an attacking V. mandarinia, packing nearly 1000 of themselves around their enemy until it dies from their body heat.
The European honeybees popular here in America, don’t have that defense. When a swarm of Murder Hornets attacks, they’re helpless. Since honeybees are important for the pollination of our crops, this represents a significant danger to our food supply.
What Happens If A Murder Hornet Stings A Human?
Can the world’s largest hornets kill a human being? The only honest answer is, yes but there are several caveats to go with that answer.
Whereas bees can only sting one time then lose their stingers, wasps and hornets have long, curved stingers with few barbs on them. This allows them to withdraw their stingers instead of leaving them stuck in their victim, so they can sting multiple times.
The venom in a honeybee is actually stronger, ounce for ounce than the venom in a murder hornet. However, because of their larger size, V. mandarinia can inject nearly seven times more venom with each sting. And remember, they can sting many times.
The larger quantity of venom injected with each sting, coupled with their ability to sting multiple times, does, in fact, make them deadly to human beings. How many stings are required for a lethal dose will depend on the size of the victim.
The venom from wasps and hornets is also much more painful than the venom from bees. The sensation from each one has been described as being akin to being jabbed with red-hot thumbtacks – each time you’re stung.
Anything more than four or five stings from them will not only create tremendous amounts of pain, it could be fatal as well. This brings up a secondary problem, ordinary beekeeping suits won’t protect you from their stings.
Specialized beekeeper suits with multiple layers of fabric are required to protect people from Murder Hornets. Their long, thin stingers will easily penetrate regular bee suits, which, basically, are nothing more than heavy coveralls with a helmet and gloves.
Therefore it’s lucky they aren’t particularly aggressive toward people, pets, or livestock. Their main prey is other insects, primarily honeybees, using their mandibles to decapitate and kill them.
However, if you disturb their nest, they will defend it, especially during the late summer and early fall when the colony is preparing for the birth of the males.
How To Get Rid of Murder Hornets If You See One?
Unless you’ve got a specialized beekeeper suit, you should note where you saw the hornets and report it. The government has created an Invasive Species app for your smartphone or you can use their web site to file the report.
It will ask you several questions about where and what day of the month you saw the hornet, what species you think it was, the state and county where the sighting took place, and – if you know it – the latitude and longitude where it occurred.
If you’re a beekeeper and you want to protect your beehives from depredation you can place robbing screens across the entrances to the hives. Most of the hive entrance is covered by #8 wire mesh, leaving only a narrow gap as the entrance to the hive.
This narrow gap is much easier for honeybees to defend than the entire entrance. The hive itself will still emit the odors that attract V. mandarinia in the first place, but at least your bees will have a fighting chance against their larger, stronger predators.
If you don’t have bees, your chances of being attacked by the hornets are slim. If you want to protect your family though, most any pesticide useful for stopping wasps will kill them as well. It might take a little longer because of their size but it will work.
- Delta Dust, used with a bulb duster, can be used around all the cracks and crevices of your house to prevent them from getting in.
- Talstar, in a handheld pump-up sprayer inside or a backpack sprayer outside, will kill them as well as creating a repellent barrier.
- Tempo Ultra SC, also in a handheld or backpack sprayer, can be used.
- Because Asian Giant Hornets prefer to nest underground, spreading Talstar Granules across the yard around your house will be an excellent way to kill them and keep them out. You’ll need to use a handheld spreader to broadcast the granules.
There are many other pesticides that can be used, either inside or outside, to kill these giant hornets.
Key Points About Murder Hornets
Remember these key points and you’ll be fine:
- Murder Hornets are more interested in attacking honeybees than you
- It takes multiple stings to be fatal
- Aside from their size, they’re just hornets
- They can be killed with ordinary pesticides
