5 of the Deadliest Insects to Humans

You can make the case that insects get something of a bad rap. After all, on the whole they're hugely beneficial to humans. They kill pests (including other insects), pollinate our crops, and are even an important food source in many cultures.

But on the downside, they kill us. In great numbers. Sometimes in really painful and unpleasant ways.

Here are five particularly noteworthy such killers. (Consider this a sequel, and homage, to the classic 1978 Saturday Night Live sketch "More Insects to Worry About.")

1. Bees, hornets, and wasps

There are about 20,000 species of bees and the same of wasps. (Hornets are best thought of as a subset of wasps, though outside of a scientific context the terms are fuzzy.)

Allergies to bee and wasp stings are among the most common of human allergies. People with severe allergies can go into anaphylactic shock and die from even a single sting.

Non-allergic people usually will just have a little pain to deal with if they get stung, unless they somehow set off a swarm, in which case, allergic or not, the accumulated damage can result in serious injury or death.

Bees can only sting once, so at least if a bee nails you, you'll have the satisfaction of knowing it'll die from doing so. A wasp, though, can sting repeatedly.

It's often said of bees and wasps (not to mention various other nasty and dangerous creatures) that "If you don't bother them, they won't bother you." There's some truth to this, but only as a rule of thumb. Not every bee or wasp you cross paths with is aware of this rule, plus you may provoke them utterly unintentionally, for instance by getting too close to a hive or nest you didn't even know was there.

Not to mention there are some species of these insects that are more aggressive than others, with a very low threshold of what constitutes "bothering" them. The so-called "killer bees" of South and Central America and now parts of the United States were intentionally bred from African and indigenous South American bees in the 1950s to get a better honey producer, and instead have already killed an estimated 1,000 people.

Oh, and you'll also probably want to avoid the three inch long giant Japanese hornet. It stings repeatedly with a venom that is more toxic than that of other wasps and bees, and contains a chemical to make it extra painful, making sure that whatever damage it does to you, you'll suffer as much as possible in the process. Plus the venom releases a scent that attracts other giant Japanese hornets to sting whatever the first one thought was worth stinging. About seventy people get stung to death this way each year in Japan alone.

2. Fleas

Mostly fleas are just annoying tiny little insects that pester our pets more than us. They live solely on the blood of mammals and birds; thankfully most prefer species other than us.

However, those that do bite humans can carry deadly diseases. How deadly? Bubonic plague, which has multiple times been a worldwide pandemic, including arguably the worst pandemic in history-the "Black Death" of the 14th century that killed roughly half of the population of Europe-is spread by fleas who feed on diseased rodents and then humans.

3. Flies

Different flies cause trouble in different ways, with the lowly common housefly responsible for spreading over 200 pathogens and parasites to humans.

But the most notable killer fly is the tsetse fly of Africa. Tsetse flies are biting insects that live off the blood of vertebrates, including humans. They spread trypanosomes, which are single-celled parasites.

These parasites cause diseases in people and livestock. The human disease is sleeping sickness, an infection that starts in the blood, moves into the nervous system and then brain, and causes extreme lethargy and eventually death if not treated in time.

Tsetse flies kill an estimated 250,000-300,000 people this way each year.

4. Grasshoppers and locusts

Locusts were once thought to be distinct from grasshoppers, but are now understood to be a certain phase of some grasshopper species.

Regular grasshoppers can be pests of a sort and do some damage to crops here and there, but it's when they become Incredible Hulkized into locusts that things get really scary.

When certain grasshoppers are in a state of overpopulation, the increased tactile contact of the crowded conditions releases serotonin which encourages them to eat and breed even more, hence making the overpopulation situation worse. Eventually a tipping point is reached, and they form a nomadic swarm that sets off in search of food.

Thankfully the six inch long locusts are extinct, but even the typically two inch long ones that remain can form swarms that extend for miles, darkening the sky, interfering with air and land travel. Carried by wind currents, swarms can even cross oceans to different continents.

Few grasshoppers and locusts are carnivorous, and the ones that are mostly just eat insects, so you don't have to worry so much about them attacking and killing you.

Not directly, that is. But they kill massive numbers of people indirectly. A locust swarm consumes every edible plant in its path. The consequences are clearly devastating to agriculture. Whole harvests can be wiped out, leading to widespread famine.

5. Mosquitoes

Mosquitoes would be decidedly annoying and unpleasant even if they didn't carry disease. The bites of these bloodsuckers can itch like crazy, and the humming of their wings can keep us awake at night.

But obviously what makes them so bad for humans is their role in spreading disease.

The diseases carried by mosquitoes to humans include dengue fever, elephantiasis, encephalitis, West Nile fever, and yellow fever.

But worst of all is malaria, carried by the anopheles mosquito. Malaria strikes hundreds of millions of people per year, killing one to three million of them.

There are other insects that make their share of trouble, but these are enough to worry about for now. Pleasant dreams.

Sources:

David Johnson, "Most Dangerous Insects: Mosquitoes, Flies, Bees and Wasps, and Other Insects." Fact Monster.
"Locust Plagues." Essortment.
"Top Ten Deadliest Insects." Crunkish.