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Stinging Caterpillars Identification and Guide
Stinging Caterpillars: Identification and Distribution
Can caterpillars sting you? The answer is YES, some can. These species use sharp spines or stiff hairs to sting as a means of self-defense. Most caterpillars are copletely harmless. Many have spines or fur, and even then most of the time they are completely harmless. There are a few species of stinging caterpillars, however. They use stinging spines or hairs as protection against predators such as lizards and mammals. Your reaction to these stinging substances may be as small as a minor rash to as serious as a trip to the emergency room.
How Can You Tell If It's a Stinging Caterpillar?
Although many caterpillars look alike, with a little practice you can learn to easily identify the most common stinging caterpillars. I have studied insects, including caterpillars, for nearly forty years. In this guide I will show you pictures and give you information so you can tell the stinging from the non-stinging caterpillars without too much trouble. Look here for photos and descriptions of some of the most common stinging caterpillars in North America.
While none of these caterpillars can kill you, some can give you a serious sting that can last for a week or more. If you're stung by a caterpillar and you feel short of breath or begin to experience swelling, call 911 immediately -- some people are allergic enough to require medical treatment, especially when stung by the Asp (see below).
It's always good to know as much about the natural world as you can, and some things, like stinging animals and insects, are a matter of personal safety! So while the vast majority of caterpillars are completely harmless (except to leaves), there are some, like the bad boys in this lens, that are definitely worth getting to know. For example, there's a caterpillar in the tropics that can and does kill people (for more about this insect, have a look at this article: A Caterpillar That Can Kill You.
Stinging Caterpillars? Caterpillars Can Sting?
Yes, Some Can!
Caterpillars, like all animals, are very interested in their own survival. Over millions of years, they have evolved an array of defensive techniques to give them a better chance of making it to adulthood. Most caterpillars are camouflaged to blend in with their environment, and that's why you don't see them every day, even though you walk right past them. Others have eye-spots to make them look like snakes or frogs, and still others are bad-tasting or even poisonous to birds and other predators. The caterpillars I'll be talking about here are the ones who have developed stinging spines or hairs. Most are merely irritating, but a few can really mess you up for a few days -- think burning pain and swelling. I hope that you never find out about these caterpillars the hard way, but if you do get stung by a caterpillar, I can at least help you figure out what it was.
Stinging Caterpillars: The Saddleback Caterpillar
I found a few of these once on my grandfather's apple tree when I was a kid. Being a kid, I had to see if it was true that they stung -- and I found out. My arm itched and burned for the rest of the afternoon, like a stinging nettle itch that doesn't fade away for several hours. These caterpillars, are in the family Limacodidae, which has a number of similar, slug-like caterpillars, many of which sting. You may well encounter one of these guys when you're gardening. Like a lot of stinging caterpillars, they are slug-like and slow. Getting them to move out of your way is probably pointless, so use a stick or leaf to roll them off, if need be, onto the ground. They'll find their way back to the food source eventually.
Stinging Caterpillars -- the Stinging Rose Caterpillar (Parasa indetermina)
This striking caterpillar can sometimes be common on rose bushes, where gardeners occasionally brush up against them and receive a sting. There are several species in the Parasa genus, all quite similar. The moth of this species is really attractive, often nearly completely a lovely shade of green. It's quite well camouflaged, though, so you'll probably never see one in real life.
Stinging Caterpillars: The Asp
This is the most common stinging caterpillar and also one of the most toxic. If you have ever been stung by an "asp," as they're known, you will likely remember it for a long time -- which, from the caterpillar's point of view, is the whole point.
These insects are technically in the family Megalopygidae, but the common name for these odd creatures, "asp," is more descriptive -- it refers to the snake-bite severity of their sting. For a caterpillar that looks a little like Elvis, it packs a fierce sting. Sources have described the bite of the asp as "often very severe, radiating up a limb and causing burning, swelling... with headache, abdominal pain, skin rashes and blisters, and even chest pain or difficulty breathing." (Eagleman 2008) Allergic reactions to asp "bites" can be scary but are not typically life-threatening. Still, if you or someone you know is stung by one of these bad boys, you should call your doctor right away.
Another Look at the Asp, or Puss Moth Caterpillar - Fresh from the hair stylist...
These stinging caterpillars come in a variety of shades and "hairstyles." This brown version is more common in the southeast. Sometimes these caterpillars will drop out of trees on their way to burrowing into the ground to pupate. Occasionally they'll land on a person, on the back of a neck or an arm, and that's when most stings occur.
This is NOT a Monarch Butterfly
Stinging Caterpillars: The Spiny Oak Slug
One of the most gorgeous caterpillars out there, in my opinion, but still capable of giving you a sting. It's not super-poisonous, but you'll definitely feel the burn. All of those little spines on the insect's back contain an irritating venom, and if you brush against it you'll get stung. The bright colors, as with many stinging caterpillars, are probably a way of warning predators, and people, from even getting close enough to find out how poisonous this animal really is.
This Stinging Caterpillar Can Kill You.
The larva of Lonomia obliqua
Stinging Caterpillars: Norape ovina
Another seldom-encountered but venomous caterpillar is the larva of Norape ovine, a Limacodid that occurs in much of the eastern United States. These caterpillars are small but easy to spot, with their bright white markings on a dark background. The venom is conveyed by special hairs that are hard to see, but when they brush your skin, you'll feel a sting. I have found the adult moths to be not uncommon, but I've never seen the caterpillar in nature.
Stinging Caterpillars: The Monkey Slug Caterpillar (Phobetron pithecium)
Truly a weird critter, even in the company of other weird critters. The monkey slug bears stinging hairs on its "arms," which are not really arms but just fleshy appendages sticking out from the animal's sides. These caterpillars are not terribly common, but if you come across one handle with care, because the hairs can give you a wasp-like sting. They become an inconspicuous moth called the "hag moth." For more photos of the adult insects these stinging larvae become, check out the photo gallery near the end of this lens.
What Do I Know About Insects?
My relationship with insects goes way beyond a passing interest. I am truly bug-obsessed: I camp alone in jungles and deserts, seeking insects tp photograph and record; I donate specimens to museums and studies; I am in the process of building an online database of all the insects on a small island in Panama. I also draw insects, and I currently have an exhibit of original pen-and-ink artwork on display at the local nature center.
Stinging Caterpillars: Isa textula
Another caterpillar in the Limacodidae family, Isa textual is sometimes known as a "crown" caterpillar due to its nearly spherical shape and spiky edges. The moth doesn't have a common name and is relatively uncommon, but it's a pretty faun color with furry legs. You will on occasion find these larvae on maple trees in early fall, and if you do you should treat it with respect.
Stinging Caterpillars: The Io Silk Moth
These caterpillars eat the leaves of roses and related plants, and often stay together in groups of a dozen or more. I have raised these caterpillars from egg to adult, and of course had to see if they really sting. I can safely report that they do. My arm was red and burning for about an hour. It wasn't intense, but it definitely made me give these big, showy caterpillar a little more respect.
Another view of the Io moth caterpillar:
Stinging Caterpillars: The Buck Moth Caterpillar
These insects are not particularly common, but once in a while they'll undergo a population explosion and you'll find them munching away on your backyard oak tree. They travel in big groups, and when you find one you usually find a bunch. The spines are extraordinarily sharp and a bad sting can linger for more than a week. These guys are related to the io moth.
Stinging Caterpillars: The White-Marked Tussock Moth
In my experience these caterpillars do not sting, and I have handled tons of them, because they're among the most common caterpillars in North America. But they do have irritating spines, and if you're sensitive to insect bites and skin irritations in general, you should probably steer clear of these amazing-looking caterpillars. They tend to have population explosions on a wide variety of trees, including ornamental varieties planted along parkways and in public plazas.
And Here's a Stinging Caterpillar That Can Actually Kill You: Lonomia obliqua (Saturniidae)
This South American species is related to the stinging io and buck moth caterpillars described on this lens. Unfortunately for its victims, the sting possessed by this caterpillar can lead to uncontrolled internal bleeding and death. In rural areas of South and Central America, Lonomia oblique caterpillars often rest on tree trunks, where they are very well camouflaged. Farmers and other people working outside sometimes brush up against them, and in severe cases the sting can be fatal.
Please note that there are no caterpillars in North America, Europe, or other temperate parts of the world that are similarly toxic!