Mosquitoes, Spiders And More Of The Most Dangerous Bugs In The World

Warm summer weather means more insects — along with more people trying to enjoy the outdoors while avoiding pesky pests. However, some are more than a mere nuisance. Although bugs are a crucial part of the ecosystem, some small creepy crawlers pose big threats to humans and animals. From having poisonous venom to carrying deadly diseases and more, these bugs are some of the most dangerous in the world.

Sydney funnel-web spiders

Sydney, Australia, may be one of the safest cities in the world, but that's no thanks to the funnel-web spider, which has sharp fangs and a bite that can kill. The Sydney funnel-web spider is native to eastern Australia and prefers a cool, covered habitat. While its bite can be deadly, an antivenom was created in 1981, and since then only one person has died from the spider's bite.

Bullet ants

While some ants will only spoil your backyard campout, the bullet ant is known to have the most painful sting of any insect. Bullet ants are commonly found in parts of South America. When the nest of a bullet ant is disturbed, they swarm out and relentlessly sting their intruder.

Kissing bugs

Kissing bugs, also known as "cone-nose bugs," are slightly larger than the size of a penny. They are often infected with the parasite that causes Chagas disease, which can be life-threatening. In the United States, kissing bugs can be found in 28 states, including Texas, New Mexico and Arizona.

Deer ticks

When warm weather rolls around, so do ticks. But, the most dangerous tick to animals and humans is the deer tick, which carries a few diseases including Lyme disease, anaplasmosis, and babesiosis. While the severity of tick-borne illnesses varies, the Centers for Disease Control and Prevention has reported a steady increase in Lyme disease cases in the U.S.

Africanized honey bees

Africanized honey bees, also referred to as "killer bees," are a hybrid between the African honey bee and one of several European honey bee subspecies. The Africanized honey bee, which can be found in the Americas, is a threat because of how fast and how furiously it attacks intruders. Since their arrival in Brazil, Africanized honey bees have killed around 1,000 people. They have continued to spread throughout South America, Central America and Mexico at a rate of about 200 miles per year.

Black widow spiders

Black widow spiders, which are found in every U.S. state except Alaska, are about the size of a half-dollar and typically have a red hourglass shape on their backs. While the black widow spider usually only bites if it feels threatened, its bites are painful and can even require a trip to the hospital. Black widow spiders can be found around gardening tools or gloves, sheds, corners of garages and other dark, undisturbed areas.

Fire ants

Using the word "fire" when talking about insects already makes them sound quite scary. And red imported fire ants are certainly not something to mess with as they got their name from their painful sting, which injects their victims with toxic venom. Fire ants were introduced to the U.S. in the 1930s from Brazil. And they're quite resourceful. In fact, during floods, fire ants will connect, form into a ball and float until they reach dry land.

Asian giant hornets

While recently this insect has been referred to as a "murder hornet," their official name is Asian giant hornets and they live up to their name as the largest wasps in the world. The hornet is native to East Asia and Japan, and while no one knows how they arrived in the U.S., they can be very detrimental to honeybee populations and their stings kill 30 to 50 people each year in Japan.

Bed bugs

Bed bugs are masters at hiding — there's evidence they've plagued humans around the world for thousands of years — and infestations of these critters should be taken seriously. Bed bugs can be found in hotels, on your luggage, and even in folded clothes. And while they aren't known to carry diseases, bed bugs can cause loss of sleep and even secondary skin infections brought on by itching.

Brown recluse spiders

Kentucky may be home to some places you didn't know were haunted, but the spookiest part about the state is definitely the brown recluse spider, which is found throughout the south-central and Midwestern United States. While the brown recluse is not known to be aggressive, their bites can become swollen, red and last for about three weeks. However, children, the elderly and patients in poor health can have more severe reactions to brown recluse spider venom such as fever, chills, dizziness, rash or vomiting.

Baboon spiders

Similar to their relatives tarantulas, African baboon spiders are large and hairy with prominent fangs. The pain that their bite inflicts can last for about a day or two and, when threatened, the spider will not hesitate to bite.


While your children play outside this summer, make sure you check them for head lice afterward. Head lice are found worldwide, but in the United States, there are an estimated 6 million to 12 million infestations each year among children 3 to 11 years of age. While the bugs themselves aren't dangerous, they are hard to get rid of, can spread easily and can cause secondary infections brought on by itching.

Velvet ants

Commonly referred to as "cow killers," velvet ants are actually a type of wingless wasp. Found throughout the U.S., they can be identified by their red-orange and black markings. The female velvet ants are the ones to be wary of due to their highly potent sting.

German yellowjackets

The German yellowjacket arrived in the U.S. in the 1970s and is very prevalent in parts of California. The reason they're a threat is due to their tendency to create nests in attics and walls of buildings in close proximity to people. German yellowjackets will start new colonies in the spring, and by July, there can be over 4,000 wasps living in a single nest in your house.

Indian red scorpions

India may be one of the most relaxing places to visit after retirement, but the Indian red scorpion is certainly not the reason why. The Indian red scorpion is considered the most lethal scorpion in the world. The primitive creature is small, often lives near people and has potent venom in its sting that can kill someone in less than 72 hours if left untreated.


While cockroaches may not seem threatening compared to stinging or biting bugs, these nuisances pose a health risk due to the allergens they possess, which can trigger allergic reactions or asthma symptoms, especially in children. Likely to be found in populated cities like New York City, these pests can spread dozens of other bacteria from E.coli to salmonella.

Wolf spiders

Hate to break it to you, but it's likely you've come in contact with a wolf spider in your lifetime. Found worldwide, there are over 200 different species of wolf spiders native to North America. Their bites contain venom, but they're not lethal. The main reason you should fear these critters is because of the way the females carry their eggs — in a sac on their backs. If you squish a female wolf spider, hundreds of spiderlings can be released.


While you likely find houseflies to be a nuisance at backyard barbecues and house parties, they shouldn't be ignored. Houseflies can actually spread diseases because they feed freely on anything from human food to dead animals. When a fly picks up bacteria, it can survive on the outside of the fly for a few hours. But when disease-causing organisms are ingested by the fly, they can survive in the fly's gut for days.

Saddleback caterpillars

Some caterpillars may look adorable, but others are not to be messed with. The saddleback caterpillar can be found in the eastern United States and is recognizable because of its bright colors and poisonous spines. Its venom can cause erucism, a condition associated with headaches, hemorrhaging and anaphylactic shock.

Tarantula hawks

While the desert might make for a cool photo spot, you should avoid any blue, iridescent bugs while you're there — it could be a tarantula hawk. In the United States, this wasp is typically found in the deserts of the Southwest, but it also lives in many places around the world. A female tarantula hawk, which hunts tarantulas to feed its larvae, has one of the most painful insect stings in the world.

Harvester ants

While Florida and California may seem like nice places to vacation, they're two states where you're likely to find harvester ants. These ants, found west of the Mississippi River and in Florida, can sting and bite. On top of being painful, harvester ant stings inject venom into the skin that can potentially cause a life-threatening allergic reaction.

Tsetse flies

If you thought the housefly was bad, try encountering a tsetse fly. These critters are found in sub-Saharan Africa and can transmit African trypanosomiasis, known as "sleeping sickness" among humans. Some parts of Africa are uninhabitable because of the tsetse fly.


Termites are a pest found in every U.S. state except Alaska, though they are more common in the South, Southeast, West and Southwest United States. While termites may not be poisonous creatures like some of the other insects and arachnids on this list, they are still dangerous. Termites can cause damage in your home that enables mold issues, which can lead to various health problems. If someone in your home is exhibiting chronic symptoms of the common cold, you could have a mold problem caused by a termite problem.

Southern flannel moths

The Southern flannel moth, which can be found from New Jersey to Florida but is most abundant in Texas, is a fuzzy little critter with a wingspan of about 1 inch. However, it's not the moth form you need to watch out for. The spines of its larva, known as puss caterpillars, are venomous and the severity of the sting depends on the thickness of your skin where you're stung. Immediately following the sting, burning pain and swelling occur.


According to the CDC, mosquitoes are the world's deadliest animal. The insect is responsible for killing more people than all of the wars in history combined. Why? Because of the diseases it carries. Aside from malaria, mosquitoes are also responsible for infecting people with West Nile virus, dengue and yellow fever. Mosquitoes can be found all over the country so make sure to stay safe and wear repellant when spending time outdoors, including visiting the most beautiful places in America's state and national parks.