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Thursday, 20 May 2021
Murder Hornets in Canada | Can Asian hornets kill you?

Murder Hornets in Canada | Can Asian hornets kill you?

As the giant insects begin to build nests this spring, scientists in the United States and Canada are opening new fronts in the fight against the so-called murder hornets.

The fight to prevent the apex predators from gaining a foothold in North America and the pacific northwest is being fought primarily in Whatcom County, Washington, and the surrounding Fraser Valley of British Columbia, where the hornets have been spotted in recent years, according to scientists.

What is a murder hornet?

Known as the world's largest hornet and a predator of honeybees and other insects, Asian giant hornets (vespa mandarinia) are an invasive species not native to Canada. 

The queens of this species grow to be over five centimetres tall, while the workers are only around four centimetres long. Giant hornets have an orange head and a dark thorax, with yellow, black, and brown bands on their abdomens.

Giant hornets can be found in Asia, from India to Japan. Their range also includes some areas of the Russian Far East in the south, as well as parts of Southeast Asia. Asian giant hornets live in colonies and are social wasps. They typically make their nests underground, such as in abandoned burrows or tree root cavities.  When they raise their nest above ground, it is normally no more than two metres.

The hornets, like other social wasps, construct a new nest every year. Asian giant hornets’ prey on a variety of insects, but honey bee attacks are the most common. When these wasps assault bees, they chew off the heads, abdomens, and legs before transporting the protein-rich thorax back to their nest, a behaviour seen in other hornet species.

Giant hornets, on the other hand, have a unique ability to consume honey bee broods. When hornets infiltrate a honeybee hive, they may go into a slaughter process where they destroy bee after bee. A small group of hornets can wipe out an entire honeybee colony in a matter of hours.

Life cycle of the deadly hornet

The hornets, like other social wasps, start a new nest each year after emerging from their winter dormancy, which is started by a single queen. The queen will raise broods of female workers, who will eventually take over foraging and nesting duties as the colony grows. 

New queens and males are created and mate before winter arrives to ensure the next generation. The current year's colony and the males die out, and the new queens find a safe place to spend the winter.

How do I recognize Asian giant hornets?

The following are distinguishable features of the Asian giant hornet that you should look out for:

  • The almost entirely dark belly, except for the fourth segment, which is yellow, is a distinguishing characteristic.?
  • Leg tips are bright yellow (native hornet dark)?
  • Thorax that is entirely brown or black (native hornet more orange)?
  • Workers can grow to be up to 25mm long?
  • European Hornets may be active at night, but Asian Hornets are not. The queen of the Median Wasp is smaller, has some yellow on the thorax (unlike the Asian Hornet), and lacks the Asian Hornet's characteristic feet and abdomen.?

As the insects made headlines, news of Asian giant hornet sightings poured in from all over North America. Many people are concerned about the 'murder hornet' craze, but there are a variety of wasps native to North America that could be mistaken for an Asian giant hornet.

Wasps that are mistaken for the Asian giant hornet

  • The bald-faced hornet (Dolichovespula maculata) is a North American native. This species is smaller than the Asian giant hornet, and its black and white coloration distinguishes it.?
  • Woodwasps (Siricidae), also known as horntails, are solitary wasps that resemble giant hornets in size. Horntails, on the other hand, have a much more cylindrical body and are totally harmless to humans. An ovipositor is a long, sting-like protrusion from their abdomen.?
  • Cicada killers (Sphecius) are similar in size to Asian giant hornets and are native to the United States. They are a solitary species that digs nests in open areas and use their stings to paralyse cicadas. These are put in their burrow on which they lay their eggs. The larvae feed on the cicada when the eggs hatch.?
  • In the eastern parts of North America, the European hornet (Vespa crabro) is well known. The Asian giant hornet is similar in size, shape, and colour, but the abdomen is mostly yellow with few dark bands and spots. European hornets typically build their nests in natural cavities such as hollow trees, about two metres above the ground.?

What do I do if I find an Asian giant hornet?

It is most likely to be seen near beehives, so beekeepers should be on the lookout. From February to November, they can be found in suburban areas.They generally nest in trees and man-made buildings, sometimes closer to the ground.

If you do happen to find a wasp or a nest, then it’s important to know the following information:

  • To avoid a group attack, stay away from their nests. They rarely sting without provocation.?
  • Do not flee. They can fly faster than you can run, and they are fascinated by moving targets, so running is considered a provocation. Crouch low to the ground, stop turning, and cover your head as best you can.?
  • Bright colours entice giant hornets, so dress in brown or black.?
  • Perfume and aftershave entice them.?
  • The scent of alcohol irritates them as well.?
  • Sightings should be reported to an extermination company who can provide tailored residential, commercial, and agricultural services to remove and control the wasps and nest.?
  • Under no conditions should you disrupt or provoke a live hornet nest.?

Is a hornet sting dangerous?

Although the venom of Asian giant hornets is less toxic than that of other insects, the wasps will inject more venom per sting. The stinger is long enough to penetrate heavy, protective clothing like those worn by beekeepers.

The nests of this species will be protected. They can be more aggressive than other hornet species because they strike in groups, recruiting other colony members to participate in the stinging. It's best to stay away from their nests, but hornets won't go out of their way to sting humans. When it comes to honeybees, however, they have more dangerous motives.

Effects on Humans

The sting is unpleasant, but the swelling and discomfort usually go away after a few days. An allergic reaction, also known as anaphylaxis, may send people to the hospital, much like honey bee stings. Extreme reactions can be fatal in very rare circumstances. 

They can be harmful to young children and people with chronic health conditions because of the amount of venom they can administer with multiple stings. In Japan, however, wasp and hornet stings killed less than 13 people per year in 2017 and 2018.

So, are they dangerous?

Their terrifying name stems from their violent and lethal behaviour against honeybees, not humans. Although honeybees can try to defend themselves by stinging their attackers, Asian giant hornets are armoured and much larger.

Are there Asian hornets in Canada?

In 2019, the Asian giant hornet was discovered in British Columbia for the first time. On Vancouver Island, a nest was destroyed in Nanaimo, and one hornet was discovered in White Rock. In December of this year, another individual hornet was discovered in Washington State.

It is unknown how the Asian giant hornet arrived in North America or how many times it has been introduced.

If you see an Asian giant hornet, call 1-877-424-1300 to report it to the Agricultural Information Contact Centre (AICC). You can submit a digital picture of a physical specimen you assume to be an Asian giant hornet to the AICC at, along with your location and postal code. For species confirmation in photos, a clear image of the specimen is needed. Follow the guidelines for sending photos below to aid in identification:

  • Ensure that all photographs are in colour and sharp.?
  • Please include photos of the following perspectives:?
    • The insect's back surface?
    • The insect's perspective?

Preventive tips to avoid hornet stings

If you find a wasp nest or live and work in an area where wasps are common, then you can do the following to ensure your safety and avoid being stung:

  • Perfumed soaps, shampoos, and deodorants should be avoided.?
  • Wearing cologne or perfume is not a good idea.?
  • Avoid bananas and toiletries with a banana smell.?
  • Wear clean clothes and shower at least once a day. ?
  • Cover as much of the body as possible with clothes.?
  • Maintain a safe and clean environment. Social wasps flourish in areas where people throw away food.?
  • If a single stinging insect is flying about, remain calm and quiet.?
  • If you are surrounded by a swarm of stinging insects at the same time, flee. When bees sting, they release a chemical that attracts other bees.?
  • Go inside.?
  • To avoid insects, a shaded environment is preferable to an open area.?
  • If you can physically get out of the field, do not try to leap into the water. Some insects are known to hover above the water and sting even after you have surfaced for air.?
  • If a bee enters your vehicle, slowly come to a stop and open all the windows.?
  • People who have had serious allergic reactions to insect bites or stings in the past should consider carrying an epinephrine auto injector (EpiPen) and wearing a medical identification bracelet or necklace that states their allergy.?

Treating a Sting

If you, or someone, is stung by a bee, wasp, or hornet, take the following steps:

  • Keep an eye on the person to make sure they are not having an allergic reaction.?
  • Soap and water should be used to clean the area.?
  • Using gauze wiped over the area or a fingernail scraped over the area, remove the stinger.?
  • Never use tweezers or squeeze the stinger.?
  • To minimize swelling, apply ice.?
  • Scratching the sting will only worsen the swelling and infection risk.?


Have a wasp infestation at home? 


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