Beware of the World’s Most Dangerous Insects

We recommend you get to know these most dangerous insects in an effort to stay safe.

While insects serve a crucial role in our ecosystem, several people find them terrifying. Not only do they look scary, but a sting or bite from one of the dangerous insects on this list can also result in extreme pain and even fatality in some cases. Needless to say, we don’t blame you for wanting to avoid them.

Luckily, some are very easy to avoid, as they live in far-flung locales, but we can encounter others like ants, bees and wasps at any time. So, we recommend you get to know these most dangerous insects in an effort to stay safe.

Note: If you believe you have an infestation of any of these insects, contact your local pest control company to remove them safely.

25. Harvester Ants

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Where they can be found: The southwestern U.S. and Mexico, Canada and parts of South America.

Notable features: Red, brown and black in color, harvester ants are about a half-inch long and sometimes mistaken for fire ants.

What to Know About Harvester Ants

Red fire ant worker on tree. focus on head.

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Harvester ants live around homes but do not usually come inside. They destroy grass and vegetation to build substantial ant hills. They stay out of sight during the hottest hours of the day and only attack when their nests are disturbed. But be forewarned — their stings are said to be more painful than those by fire ants.

They are capable of stinging more than once and will do so repeatedly. These aggressive ants can kill small animals but not necessarily humans. However, the pain from their sting can last several hours and can cause severe allergic reactions.

24. Brazilian Wandering Spiders

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Where they can be found: Costa Rica, Colombia, Peru, Brazil and Paraguay.

Notable features: Hairy and brown with a black spot on their bellies, they are large, with a 2-inch body and 6-inch leg span.

What to Know About Brazilian Wandering Spiders

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The Brazilian wandering spider is one of the most venomous spiders on Earth. They don’t weave webs as spiders usually do — instead, they travel to seek out their prey. Luckily, your chances of running into one are pretty slim, but they have been found in shipments of bananas (hence the name “banana spider”) to the U.K.

Their venom is not only painful, but it can also cause chills, fever, blood pressure fluctuations, nausea, hypothermia and convulsions. It can also cause an uncomfortable erection, which is sometimes how doctors can tell someone has been bitten. Their venom is currently being studied by scientists for use in erectile dysfunction medications.

23. Deathstalker Scorpions

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Where they can be found: North Africa and the Middle East.

Notable features: Pale yellow-brown with light-brown spots.

What to Know About Deathstalker Scorpions

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With a name like “deathstalker,” you know this scorpion means business. It probably won’t kill a healthy adult, but for children, seniors and those with compromised immune systems, it can be fatal. Its venom consists of neurotoxins and cardiotoxins — its sting causes severe pain with a possible allergic reaction to follow.

Victims are known to develop pancreatitis after getting stung. For those whom the sting proves fatal, their cause of death is usually pulmonary edema — a build-up of fluid in the lungs. The deathstalker’s venom is also sometimes resistant to antivenom treatment.

22. Arizona Bark Scorpions

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Where they can be found: The southwestern U.S. and northern Mexico.

Notable features: They are tan and blend in with their desert surroundings; however, under UV light, they glow a bright blue color.

What to Know About Arizona Bark Scorpions

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All scorpions are dangerous to some degree, but the Arizona bark scorpion holds the distinction of being the only scorpion in the U.S. that can be lethal. Known for its painful, venomous sting, they are occasionally kept as pets. They can kill people with compromised immune systems, children and the elderly.

The bark scorpion is not aggressive; however, when threatened, it will sting. Outside of severe pain, victims can experience convulsions, respiratory issues, muscle twitching and numbness and death.

21. Saddleback Caterpillars

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Where they can be found: Eastern North America and parts of Mexico.

Notable features: Furry green in the middle with brown at its ends and a brown dot in the center, resembling a saddle.

What to Know About Saddleback Caterpillars

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You may want to touch this adorable, odd-looking caterpillar, but don’t — its spines pack quite a painful punch, as they are connected directly to its poison glands. People who have been stung say the pain from the saddleback rivals or surpasses that of a bee sting.

This caterpillar stings by embedding its spines in the skin, and the burning pain they cause can last for several hours. It is possible to remove them with tape, but if you have a greater reaction due to allergies, you should contact a doctor immediately. Symptoms include migraines, gastrointestinal issues, asthma anaphylactic shock and hemorrhaging.

20. Wheel Bugs

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Where they can be found: North America, Mexico and Central America.

Notable features: Brownish-gray “armor” — the largest of the “assassin” bugs at 1.25-inches long.

What to Know About Wheel Bugs

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Found in any garden or yard, the wheel bug only bites in self-defense; however, when it does, it is immediately noticeable and severely painful. It can also cause numbness at the site of the bite, which can last for days.

Usually, no treatment other than an antiseptic, aspirin or ibuprofen is needed. However, if swelling, itching, hives or respiratory issues occur, seek medical help immediately.

19. Yellow Sac Spiders

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Where they can be found: North, South and Central America.

Notable features: They look yellow-green but have dark-colored feet.

What to Know About Yellow Sac Spiders

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The yellow sac spider is venomous to humans and is quite often mistaken for the brown recluse. It lives indoors and can produce necrotizing lesions, as its venom is a cytotoxin, which destroys cells.

The most common symptoms of a bite are redness, swelling and pain at the site; however, people with allergies can also suffer anaphylactic shock.

18. Cockroaches

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Where they can be found: On every continent, except Antarctica.

Notable features: Brown with flat, oval-shaped bodies that look like a shield. They can get big!

What to Know About Cockroaches

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We’ve all had a run-in with a cockroach at least once in our lives, and while they do give off an “ick” factor, they usually scatter when the lights go on. They are not inherently dangerous to humans; however, they will bite in certain circumstances. These omnivores have been known to eat human flesh (of the living and dead!) when they’re desperate for food.

Their bites can cause swelling and infection, and they carry bacteria, including salmonella, staphylococcus and streptococcus. The World Health Organization (WHO) has also declared the cockroach to be a carrier of intestinal diseases, including dysentery, cholera and typhoid fever.

17. Indian Red Scorpions

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Where they can be found: India, Eastern Nepal, Eastern Pakistan and Sri Lanka.

Notable features: Up to 3.5-inches long, they are reddish-orange or dull brown with a large stinger.

What to Know About Indian Red Scorpions

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The most lethal scorpion in the world, the Indian Red Scorpion is not a hunter, but it will sting to defend itself if it feels threatened. Believe it or not, this scorpion is often kept as a pet and can be used for medical purposes in dermatology or cancer treatment.

They usually kill small children; however, a 54-year-old woman died from a stroke as the result of a sting in 2017. Symptoms of a sting include extreme pain, vomiting, anaphylaxis, blood pressure fluctuations and heartbeat, and pulmonary edema.

16. German Yellowjackets

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Where they can be found: Europe, Chile, Argentina, New Zealand, Australia and parts of the U.S.

Notable features: Black bodies with yellow- or white-striped markings — they look like wasps but are a bit thicker.

What to Know About German Yellowjackets

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Said to be more aggressive than American yellowjackets, German yellowjackets are an invasive species in the U.S. They build their nests indoors by burrowing in walls, which makes their encounters with humans more likely.

If a human stumbles upon a nest, these yellowjackets will do anything to protect it. They sting repeatedly and will chase any animal or human for long distances. They have extremely painful stings, which can result in death for people who are allergic.

15. Velvet Ants

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Where they can be found: The eastern and southern U.S.

Notable features: They look like ants with a fur coat of red, orange or gold stripes against black.

What to Know About Velvet Ants

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“Velvet ant” is a misnomer — these insects are actually wasps. Also called “cow killers,” they don’t actually kill bovines, but their sting is so painful it feels strong enough to kill a cow. This wasp is a ground dweller that usually keeps to itself but will strike if it is disturbed.

Those who are allergic can go into anaphylactic shock. The intense pain from the sting, even for those who are not allergic, can last up to 30 minutes. These wasps are solitary creatures — should you run into one, there won’t be dozens swarming you, which is a good thing considering how painful their sting is.

14. Bed Bugs

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Where they can be found: North and South America, Africa, Asia and Europe.

Notable features: Small, oval, brown bugs that are so small you may not even know you have them.

What to Know About Bed Bugs

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Bed bugs have been around a long time; however, their numbers decreased in the 20th century, as vacuum cleaners and pesticides were introduced. But they’ve become resistant to pesticides over the decades and are once again increasing in numbers. They are everywhere (from apartments to cruise ships), are active only at night and make their home usually in the areas people sleep.

Bed bugs do not spread disease, but their bites are itchy and can sometimes cause a secondary skin infection. In some instances, people can have an allergic reaction and may need medical treatment.

13. Black Widows

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Where they can be found: The U.S., southern Europe and Asia, Australia, Africa and South America.

Notable features: Females are black with red marks on their abdomens and are considerably bigger (and more dangerous) than males.

What to Know About Black Widows

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Black widows are some of the most venomous spiders in the world. In fact, their venom is 15 times stronger than that of a rattlesnake. Much like the brown recluse, they keep to themselves and only lash out when they are disturbed, and it’s only the female that can really do some damage.

When someone is bitten, they’ll feel a pinprick at the site, and pain will move throughout the body within a few minutes. Nausea, sweating, muscle aches, hypertension and difficulty breathing can occur. These symptoms can last several days, but luckily, there is an antivenom available. While they can make someone extremely sick, they rarely cause death.

12. Deer Ticks

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Where they can be found: North America, Europe and parts of Asia.

Notable features: Flat, oval, reddish-brown bodies.

What to Know About Deer Ticks

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Not everyone who gets bitten by a deer tick will get Lyme disease, but deer ticks do spread it. According to the Centers for Disease Control and Prevention, 300,000 people are diagnosed with it in the U.S. every year. That said, it is hard to diagnose, as it mimics the symptoms of other diseases, including fibromyalgia, meningitis and multiple sclerosis.

Sometimes, the symptoms appear to be like a cold or flu, and the only way a proper diagnosis occurs is when a tick is found on the skin or a red “bullseye” rash appears. If left untreated, Lyme disease can indeed be fatal.

11. Botflies

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Where they can be found: Mostly in Mexico, Central and South America.

Notable features: Hairy and looks like a cross between a bee and housefly with maggot-like larvae.

What to Know About Botflies

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When it comes to the botfly, there’s good news and bad news. The good news — unlike other flies, they don’t carry parasites. Now for the bad news — their larvae burrow into human skin. As matter of fact, they need a mammalian host to survive. In 2018, a Florida woman who went on her honeymoon in Belize had a mysterious itching and hole in her groin area, which was later discovered to be a baby fly that had made its home in her skin.

Once botfly eggs are in the human body, its heat allows them to hatch. This can last anywhere from 27 to 128 days. While the fly is growing, it causes painful, oozing pustules, and some people can actually feel it moving. While the botfly doesn’t have a big body count in terms of fatalities, its host’s skin can become infected, which can lead to death if untreated.

10. TseTse Flies

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Where they can be found: Sub-Saharan Africa.

Notable features: A large “nose” that extends forward and is attached to their heads by a distinct bulb.

What to Know About TseTse Flies

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A tsetse fly bite can occur without you noticing. Its mouth has tiny knife-like serrations that allow it to “saw” into your skin to draw blood. The tsetse can transmit diseases to humans, one of which is human African trypanosomiasis or “sleeping sickness.”

Victims begin experiencing minor symptoms such as fever, rash, irritability, fatigue, swollen lymph nodes, and muscle and joint aches one to three weeks after they are bitten. If left untreated, it will develop into neurologic problems and eventually death.

9. Africanized Honeybees

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Where they can be found: North and South America.

Notable features: They look almost like average honeybees, which makes them tricky to spot; however, they are a little smaller.

What to Know About Africanized Honeybees

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“Killer bees” began populating the Western Hemisphere in the 1950s. They are a cross between European and African honeybees and are more aggressive than your average bee. In fact, a loud noise is enough to send them swarming.

This bee will attack in larger numbers for a longer period, dispensing a significant amount of venom into its victims. They have been known to give chase for a quarter of a mile, and their stings can cause everything from pain to a severe allergic reaction, which can be fatal.

8. Asian Giant Hornets (aka, Murder Hornets)

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Where they can be found: Asia and the U.S.

Notable features: A black and white variation of the yellowjacket wasp and twice the length, at about 2-inches long.

What to Know About Asian Giant Hornets

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While its sting has been described as the feeling of being stuck with a hot pin, the Asian giant hornet’s sting subsides within days, but an allergic reaction can close a victim’s airways. However, as menacing as these bees are, humans are of no real interest to them.

Its “murder hornet” nickname comes from its decimation of the honeybee population. In fact, it has been known to crawl into hives and decapitate them by the thousands.

7. Fleas

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Where they can be found: On every continent, including Antarctica.

Notable features: The flea needs a living host to feed on to survive. They are tiny — about 1/8th of an inch long, reddish-brown and thin.

What to Know About Fleas

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If you have pets, chances are good that you’re familiar with fleas. You know you’ve been bitten when small, itchy red bumps appear on your skin with a ring at the center. The itching can cause scratching, which can invite a bacterial infection. Fleas also carry tapeworms, and enough bites can bring anemia.

Fleas transmit the bubonic plague, which caused the deaths of 200 million people in just four years during the Middle Ages. The plague lasted on and off until the 19th century and sometimes springs up in developing nations. Today, it is treatable by antibiotics.

6. African Driver Ants

Driver ants or safari ants (Dorylus sp) in Zambia

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Where they can be found: Central, east and southern Africa and tropical Asia.

Notable features: At nearly 2.5 inches, they are the largest living ants on the planet.

What to Know About African Driver Ants

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Driver ants, also known as army ants, are carnivores. While they usually live off earthworms, they will eat any creature that stands in their way. These nomadic ants travel from place to place in search of food; when they deplete the area of nutrients, they move on.

Driver ants haven’t killed full-grown adults, but it is said they have killed infants, who have died from dehydration, starvation or infection. Their bites are so strong that some tribes use them to close wounds as a substitute for stitches.

5. Bullet Ants

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Where they can be found: Central and South America.

Notable features: They’re BIG — over an inch long with blunt horns.

What to Do About Bullet Ants

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The bullet ant mostly keeps to itself but will attack any animal or human that disturbs its colony. Plus, it has a sting that is considered to be one of the most painful of any animal. It can last up to 24 hours and cause a variety of ailments, including severe pain, cold sweats, nausea, vomiting, abnormal heart rhythms, paralysis and shaking in the affected area.

This insect isn’t much of a killer, however, unless victims are allergic. In fact, the Amazonian Sateré-Mawé tribe gets stung by a few hundred bullet ants for its coming-of-age ritual. Ouch!

4. Brown Recluse Spiders

Brown recluse spider watching over its eggs

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Where they can be found: The southern and central U.S.

Notable features: A violin-shaped pattern pointing toward the abdomen.

What to Know About Brown Recluse Spiders

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Brown recluse spiders generally don’t come looking for trouble — they stay in places they can remain unseen, like inside a shoe or box, and it’s only when they are disturbed that they bite.

Their bites take two or three hours to manifest and when they do, they result in everything from lesions, nausea and fever to severe allergic reactions, which occur mostly in children, seniors or people with pre-existing medical conditions.

3. Kissing Bugs

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Where they can be found: Mexico, Central America, South America and the southern U.S.

Notable features: These bugs can be up to an inch long and have wings of brown or black. They sometimes feature red, orange or yellow stripes.

What to Know About Kissing Bugs

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A kissing bug will use its mouth on its victims — but not for a smooch. They bite animals and people to feed on their blood, usually in their sleep. While most bites don’t cause any real problems, they can cause allergic reactions and disease to those who are immunocompromised.

Most bites are harmless, but sometimes they can spread disease, particularly Chagas disease, which comes from a parasite in their feces. Most people have minor symptoms, if any, but some contract serious heart disease as a result of a bite. While the bug kills just 50 people a year in the U.S., its population and its number of victims are growing due to climate change.

2. Fire Ants

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Where they can be found: South America, Australia, New Zealand, several Asian and Caribbean countries and the U.S.

Notable features: Small with copper-colored heads and reddish-brown or black bodies.

What to Know About Fire Ants

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These aggressive insects tend to swarm in large numbers, and despite how small they are, they do pack a big bite, particularly when their ant mounds are disturbed. Fire ants sink their teeth into victims and do not let go. Once attached, they use their stinger to inject venom into their prey and, with it, comes a painful, burning sensation.

These stings can kill small animals easily, and if a human is stung, their venom is strong enough to cause someone to go into anaphylactic shock.

1. Mosquitoes

Black and white spotted mosquito on the surface of liquid

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Where they can be found: Every continent except Antarctica.

Notable features: These insects are usually gray with scales of white, silver, green or blue. They have long legs and a long nose that they use to siphon blood from animals and humans.

What to Know About Mosquitoes

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The mosquito is not only the world’s deadliest insect, but it’s also the world’s most dangerous animal overall. That’s because it transmits a staggering amount of viruses and parasites to humans, which cause fatal diseases like Zika virus, West Nile virus, Chikungunya virus, dengue, yellow fever and malaria, among others.

While mosquitos are becoming resistant to pesticides, there are still repellents they cannot resist. In fact, the people who never seem to get bitten produce a natural chemical repellent in their sweat, which keeps the insects at bay.