Tarantula Hawks Are Neither Tarantulas nor Hawks

Tarantula Hawk Wasp
The tarantula hawk wasp immobilizes a tarantula with a sting, then uses it as a living host in which to lay her fertilized egg. Alice Cahill/Getty Images

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Wherever you find tarantulas on this planet — or baboon spiders, the Old World equivalent of the tarantula — you will also find tarantula hawks. From the name, you might be picturing a bird of prey, but a tarantula hawk is actually an insect — a wasp of prey. And if you guessed they eat tarantulas, you'd be right — well, at least partly right.

Tarantulas are, of course, the largest of the spiders, so it would make sense that there would be an insect out there that has, at some point over the past 300 million years, looked at one of these husky arachnids and seen what amounts to an Angus heifer — enough meat to feed the family. And so, over time, tarantula wasps suited up with a long stinger — some of them are around half an inch (1.3 centimeters) long — and set out to conquer the tarantula.

"They're big, they're impressive, they're beautiful, they're strong, they're long-lived and nobody eats them," says entomologist Justin O. Schmidt, author of "The Sting of the Wild" and the creator of the Schmidt sting pain index, wherein Schmidt, who has endured around 1,000 arthropod bites and stings over the course of his career, rates the relative pain of each on what amounts to a 4-star scale.

In the United States, you can find tarantula hawks west of the Mississippi River, through Texas to California and up to Wyoming — again, tarantula hawks can be found anywhere tarantulas live. There are fewer than 20 tarantula hawk species in North America, but South America is home to around 250 species. And though you don't want to tangle with one of these big wasps — they can grow up to 2 inches (5 centimeters) long, which is the size of a small hummingbird — they are objectively gorgeous, with metallic blue-green bodies and many with iridescent orange wings. Their beauty, however, is in the eye of the beholder, and if you happen to be a tarantula, the sight of a female tarantula hawk headed your way is more appalling than dazzling.

Tarantula hawks are nectivorous — strictly vegetarian — once they pupate into adults, but before that time, the larvae are carnivorous. After mating, the female tarantula hawk needs a safe place to store and nourish her growing baby, which is why some ancient spider wasp millions of years ago, at a loss for what to do with her fertilized egg, set her sights on the tarantula — so nutritious and meaty! These days she has it all dialed in: She stings the tarantula, paralyzing it forever without killing it, and lays a single egg on its abdomen. When the baby hatches, it starts sucking the innards out of the living, paralyzed spider. When it's big enough, it burrows into the tarantula and really chows down.

It's gruesome, it's horrifying, but such is the nature of the female tarantula hawk. Because males don't need to paralyze a giant arachnid, they can't sting and are harmless. The sting of a female tarantula hawk, on the other hand, sounds like a living nightmare. On the Schmidt Insect Sting Pain Index, the tarantula wasp sting receives the most painful rating: a FOUR.

"I've had three or four stings," says Schmidt. "I've never actually let one sting me — I'm not that foolish. They're basically electrifying. If you get stung by one, it's like getting hit by 20,000 volts — you might think you'll be able to handle it, but don't believe for a minute that you can. So, my advice is to just lie down. If you're stumbling around, you may trip in a hole or hit your head on a rock or fall into a barbed wire fence, which could really do damage. I say the safest thing is to lie down and scream. People ask me, why scream? Well, it gives you something to do while you're distracting yourself from thinking about the pain. If you can scream for two minutes, by the time you've done that, it feels better and you can go about your business."

Tarantula Hawk Venom Isn't Dangerous to Humans

Strangely enough, aside from the pain, which lasts for five minutes, max, the sting of a tarantula hawk causes no reaction at all. While the venom of some insects actually destroys tissue and causes inflammation, this isn't the case for a tarantula hawk sting.

"There might be a tiny bit of white around it, but it certainly doesn't swell up the way a wasp or a honeybee sting swells, with a big white wheel around the sting site and a big red flare that's hot, achy, itchy and painful," says Schmidt.

The reason has to do with the chemistry and function of the venom. A honeybee's venom has two purposes: to be painful to animals attacking the hive, and to actually injure — maybe even kill — the intruder. For instance, if a mouse gets into a honeybee colony, it could wreak havoc on the entire nest — especially in the winter when they're sluggish. Of course, mice are much smaller than we are, but just a handful of bee stings can kill a mouse — at the very least, bees have a way of getting it out of the nest.

Tarantula hawk venom has two functions as well: the first one is to inflict pain on anybody messing with them, and their venom does a superb job of that. The other purpose is to cause permanent, total paralysis in the tarantula.

"People have kept paralyzed tarantulas in the lab for months, making sure they keep them hydrated and all that," says Schmidt. "The tarantula will die six months or so later — they starve to death and can never accomplish more movement than just a little flick of the limb."

But what makes the sting of a tarantula hawk so incapacitating to a tarantula and not to us (other than the few minutes of unmanageable pain)?

"We suspect that the pain inducing factor is different from the one that causes paralysis in the tarantula," says Schmidt. "The paralysis factor probably affects the neuromuscular joint of the tarantula, which is run by glutamate — a neurotransmitter — whereas our neuromuscular junction is run by acetylcholine. We don't have any glutamate receptors in our skin — only in our brain — so their venom can't paralyze us the way it does an insect or another spider. If you artificially inject their venom into a cockroach or a cricket, it will paralyze it, but if you inject it into a mouse, it will run around and squeak because it hurts them just like it hurts us, but they recover in a couple of minutes just like we do."

Overall, Schmidt doesn't recommend being stung by a tarantula hawk, but he says there are some upsides to the experience:

"When you get stung it doesn't seem worth it, but in my opinion it's better than getting stung by a honeybee on the eyebrow — your whole eye swells up and you can't see for a day or two," he says. "The only long-lasting thing about a tarantula hawk sting is you will get to tell the story about how you survived a tarantula hawk sting. The story will survive two or three generations."