Are they really that bad?

Murder hornets…just the name implies that these are something that should be feared and this has led to many people panicking. In truth, if you see one, their size would probably scare you, but are they really a threat? Can they kill you? Why should you be concerned about them?

On May 2nd, The New York Times reported that “murder hornets” were recently discovered in Washington state. This created such a sensation that within a few days there were memes flooding the internet about them. In reality, the Vespa mandarinia, is very common in many parts of Asia, which is why it’s more often known as the Asian giant hornet. However, it does have several other names, just in Japan, it’s known as the big hornet, the yellow hornet, the great whale bee and the giant sparrow hornet (even though they really aren’t as big as sparrows). The giant hornets do have relatively toxic venom, which can cause a significant amount pain and, occasionally, death.

It’s the largest hornet in the world. It can grow between 1.5 – 2 inches long with a 3-inch wingspan. It has a distinctive yellow-orange heads with prominent eyes and large mandibles, a black thorax and yellowish/orangeish stripes on its rear end, which is pointed with a big, curved, smooth stinger. The stingers are long enough that they’re capable of piercing the protective gear normally worn by beekeepers. It also doesn’t break off when they sting, which enables them to repeatedly attack its victims. The hornet’s life cycle begins in April. This is when the queen wakes up from hibernation and looks for a spot to build a nest. She can fly up to 20 miles per hour. The hornets have the tendency to nest in hidden places, like the hollows of trees, ground burrows and cavities left behind by decaying plant roots. The nests can be large, with over 1,000 workers, but usually has only several hundred workers. All the workers are female. The queens create their first nests by themselves feeding their larvae until they hatch and become a work force. After the work force is able to collect food and maintain the nest, the queen just lays eggs. It’s important to note that her early eggs are sterile, which means that she can’t create new queens until the fall. The giant hornets feed on many different kinds of insects and they bring dead prey back to the hive to feed to their young. They’re also attracted to tree sap. They’re foraging range is only about 2,300 feet from their nest. The hornets are native to the mountainous regions of Asia because they can’t tolerate extremely hot or cold temperatures. They’re more active when the temperature reaches the upper 70s. This is most likely because they’re bigger than bees and smaller wasps, which means they’ve got a bigger mass to preheat for flight.

According to people who have been stung by the giant hornet, the sensation is like being stabbed by a red-hot needle with pain that lingers. The affected area swells severely and continues aching for a few days. The acetylcholine and histamine within the venom causes the pain and swelling. A different chemical, called kinin, dilate blood vessels. Another substance called mastoparan, which isn’t found in bee venom, and phospholipase act together to breakdown immune cells and create widespread inflammation. When combined with kinins, these destroy blood and muscle cells, which leads to the release of large molecules, like hemoglobin, that the kidneys must filter out. Unfortunately, there are several chemicals within the venom that are toxic to the kidneys specifically, which is why giant hornet attacks can lead to renal failure. The venom also contains a unique neurotoxin that blocks nerve impulses. The toxicity of the venom is substantial. According to researchers, it’s greater than the toxicity of most other stinging insects. In order to determine this, a measure called the LD50 is used. This is also known as the median lethal dose or the quantity necessary to kill 50% of test subjects (usually small animals, like mice). The less venom that is needed for a lethal dose means the more dangerous the substance is. In the 1980s, scientists found that giant hornet venom has an LD50 of 4.1 milligrams per kilogram. This is a level similar to other closely related hornets. For comparison’s sake, the LD50 of honeybee venom is 2.8 mg/kg, which means that it’s more toxic than giant hornets, but bees can sting only once. Giant hornets can sting repeatedly, which means they’re able to deliver about 10 times more venom. Per their findings, scientists stated for the venom to reach life-threatening levels, a person would have to be stung by a couple hundred giant hornets compared with about a thousand honeybees. While the giant hornet does cause between 30 to 50 deaths per year in Japan, most of them are related to allergic anaphylactic reactions rather than acute toxicity. Giant hornets, like other wasps, generally don’t attack unless bothered, especially when they’re out foraging. Most deaths occur because people seriously disturb the insects’ nests. It’s important to note that giant hornets do give a warning before they sting by flying back and forth snapping their mandibles. It’s designed to be intimidating and get your attention. They’re the only species that does this.

The giant hornet is a bigger threat to honeybees than to humans. This is why scientists and beekeepers in the Pacific Northwest are concerned. Bees are vital for agriculture due to their pollinating abilities. It’s estimated that they provide $15 billion each year to the US economy through their pollination services. According the US Department of Agriculture, bees pollinate approximately 75% of the fruits, nuts and vegetables grown throughout the country. What we know as the honeybee (Apis mellifera) was brought to North America from Europe by early colonists. Most US bees are descended from an Italian subspecies, which is known for its gentleness and honey-making ability. Unfortunately, these bees are also lack resistance to some common honeybee problems, such as parasites (varroa mites), over 20 viral and other diseases and pesticides on the food they eat. Since 2012, beekeepers say they’ve seen annual losses in hives ranging from 29 – 45% due to these problems. If the giant hornet becomes established in the US, it’ll add another stressor to vital honeybee populations. The hornets are usually solitary hunters, but between late summer and fall, the workers band together to conduct mass attacks on nests of other social insects, like honeybees. This behavior even has a name: the slaughter and occupation phase. The phase begins when a worker hornet spots a bee colony, marks it with a pheromone and then brings a backup crew of between two and 50 others. The hornets crawl into the bee hives and rips off the bees’ heads in large numbers. The large biting mouthparts enable the hornets to decapitate their victims quickly and efficiently. Within in a couple of hours, just a few of the hornets can completely decimate a hive, wiping out the whole population. During one recorded slaughter, researchers found that each hornet killed one bee every 14 seconds. Once this is completed, the hornets now have a large food source for their young.

The Asian honeybee (Apis cerana) has developed defenses against giant hornet’s slaughter-and-occupy efforts. When a hornet places her pheromonal mark on an Asian honeybee hive, all the bees stay inside the hive. If a hornet does get into the nest, nearly 400 worker bees will quickly surround it. This forms a ball of buzzing insects that vibrate their flight muscles, which raises the temperature within the ball to around 122 degrees F and increases carbon dioxide levels too. The bees can handle the conditions, but the hornet dies. However, if enough hornets attack the nest, they can overwhelm the bee defenses. Our honeybees don’t have the same instinct to respond to the scent marker or know how to form bee balls. Instead, they try to defend against a hornet attack by fighting the invaders outside the hive and stinging them, but giant hornets have rigid exoskeleton that makes bee stings ineffective. This means our honeybees are at the mercy of the giant hornet unless humans step in to help them.

Many experts were surprised that the hornets have appeared in North America. They were first discovered last fall in British Columbia and were seen in the US for the first time in December. The Washington State Department of Agriculture verified four reports of sightings between the mainland and Vancouver Island. However, genetic tests of the specimens from Canada and those in Washington state indicate that they’re not related. It’s important to note that the results have not been published or peer reviewed yet. Most likely, fertile queen hornets entered the areas via shipping packaging and created a colony. This isn’t an uncommon way for invasive species to travel this way since more than 19,000 cargo containers arrive daily at US ports and inspectors only have time to do random searches. One estimate calculates that this means just 2% of shipments are searched for evidence of harmful organisms. Even though this might not seem like a large number of containers are searched, many invasive species are intercepted. However, some do get through. As far as anyone knows, the giant hornet hasn’t appeared anywhere else in the US. Given the hornets climate preferences, they’re unlikely to spread to very hot or cold areas across North America. The Pacific Northwest has a more temperate climate, so it’s possible that they could spread there, but it’s improbable for this to happen quickly given the hornets lifecycle.

Washington State Dept of Agriculture Bee & Wasp ChartScientists are working hard trying to locate and eliminate any giant hornet populations in northwest Washington. The goal is to eradicate the hornets before they become entrenched. According to experts, this is the window to keep them from establishing a foothold and if it can’t be done in the next couple of years, the hornets will be here to stay. Finding and destroying nests is the key, but removing, or even simply approaching, the hives is dangerous work. Due to the stingers ability to penetrate standard beekeeping suits, it means that thick protective gear must be worn and specialized equipment, like vacuums help to suck the creatures out of the air. In order to find nests, Washington State officials are setting up traps in hopes of catching hornets, so they can place tracking devices on them to follow them back to their nests. They’re using clear jugs made into makeshift traps since typical wasp and bee traps have holes too small for the hornet. The devices are filled with mixtures that should attract the hornets, like orange juice mixed with rice wine. The traps are hung from trees and geo-tagged so each location is recorded. If a hornet does get caught in a trap, the plan is to use radio-frequency identification tags or attaching a small streamer to the hornet and then following it as it goes back to its nest. Another option that officials are looking into is thermal imaging. Since the buzz of activity inside a giant hornet nest keeps the inside temperature close to 86 degrees F, it would should be easy to distinguish on the forest floors. They’re also looking at tools that could track the distinct hum the hornets make in flight. In the meantime, beekeepers are looking to what the Japanese do to protect their bees. One option is to install entrance traps over the doorways of managed hives that have holes large enough for a bee to pass through but not a hornet. In Japan, they also use special traps placed in front of a beehive, which are designed to catch giant hornets before they mark the hive with their pheromone. Another possibility is using baited traps to entice the hornets to their death.

Despite the limited range that the giant hornets have been found, the media coverage has caused a national panic surrounding the hornets. This has led to the needless killing of native wasps and bees. Many people across the US have started putting out traps, but the bait in those traps is appealing to all kinds of native insects that are needed to help complete the local ecosystems. Some people might not think that killing bees or wasps of any kinds is a bad thing, but they provide many significant benefits, like eating several times their weight in caterpillars from people’s vegetable gardens and ornamental plants. This means that indiscriminately killing them does much more harm than good. The only people who should be concerned about identifying wasps are those living in the northwest quadrant of Washington state. If you do live in this area, officials want you to know that cutting down trees to prevent nesting sites is unnecessary. Also, don’t try to remove nests yourself or spray hornets with pesticides. The Washington State Department of Agriculture has a website for reporting possible sightings and sharing photos of giant hornets. In addition, they provide images of similar-looking insects native to the area. If you’re unsure if you found a giant hornet, take a photo from a distance and report it to the Washington State Department of Agriculture. You can also upload your images to iNaturalist, which is one of the main sources for evidence on tracking wildlife. Since the images are archived and carry data, like location, time of observance and the insect’s features, scientists can use them for research.

Despite their painful sting, giant hornets don’t murder people. So, where did the term “murder hornets” come from? Most likely from an improper translation. The Japanese word satsujin is written with the characters for “kill” and “person,” but doesn’t clearly distinguish between “murdered” or “killed.” This means that if you look up satsujin in a Japanese-English dictionary, there will be a list of options that include the words “murder,” “manslaughter” and “killer.” It’s up to the translator to select the appropriate word based on context. In this regard, unless you’re a honey bee, the giant hornets aren’t “murder hornets,” they’re just hornets and like any other animal protecting itself and their home will attack when provoked. While they do have special adaptations that allow them to sting repeatedly, the likelihood of dying from an attack is slim unless you have an allergic reaction to the venom or are stung by several hundred hornets. Considering that they area that they’re found in the US is limited to Washington state, most of use don’t have to worry about dealing with them. If you do live in Washington state, be on the lookout, avoid the hornets if you see them and report any sightings to officials.