Updated date:

Stinging Caterpillars Identification and Guide

GreenMind creates authoritative and detailed guides to the things you're curious about.

The buck moth caterpillar has one of the most severe stings of any North American species.

The buck moth caterpillar has one of the most severe stings of any North American species.

Stinging Caterpillar Identification

Can caterpillars sting? Yes, some can. Most caterpillars are completely harmless and rely on camouflage to avoid being eaten by a predator. A few of them, however, have evolved stinging spines and hairs. If you handle one of these stinging larvae, there's a chance you could wind up with a painful sting.

This guide presents a complete guide to the most-commonly encountered stinging caterpillars in North America. It will help you tell the stinging caterpillars from the harmless ones. Many caterpillars that have fur and spines look like they can sting, but can't. Other caterpillars, like the dangerous species known in southern states as "the asp," hide sharp stinging spines under harmless-looking fur.

It's important to be able to tell whether the caterpillar you find is able to sting you. Your reaction to these stinging substances may be as small as a minor rash to as serious as a trip to the emergency room. 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.

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 that are definitely worth getting to know.

My Experience With Insects

I became fascinated with insects when I was five; 50 years later, and I'm still just as fascinated. I have worked in the field in various capacities for 30 years, and today I'm a dedicated citizen scientist with an ongoing project to catalog the night-flying insects of Bocas del Toro, a small island in Panama. For this project, I'm working with a permit from the Smithsonian Institution, and hundreds of my finds are in the permanent collection at the Universidad de Panama. Images and descriptions of the species I have found in the course of this project are published at panamainsects.org.

Other than my guides here on HubPages, I maintain a Facebook page, Caterpillar Identification, that has several thousand followers. On this site I frequently identify caterpillars posted by people around the world.

The caterpillar known as "the asp" hides a powerful sting under fluffy-looking fur.

The caterpillar known as "the asp" hides a powerful sting under fluffy-looking fur.

The Asp: Megalopyge opercularis

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. The sting of this species has been described 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 caterpillars, you should call your doctor right away.

The Basics:

Scientific name: Megalopyge opercularis

Food Plant: oak, elm, wild plum, and other plants

Range: Southeastern US, but occasionally found farther north

Adult Moth: Called "flannel moths," they are medium-sized moths with thickly scaled wings.

Severity of Sting: Can be very painful and long-lasting; the most potent of North American caterpillar stings


Another Asp "Hairstyle"

stinging-caterpillars

The Asp's "Fur" Comes in Several Colors

Sometimes called the Elvis caterpillar, stinging asp caterpillars come in a variety of "hairstyles." The 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.

Saddleback Caterpillar

stinging-caterpillars

The Saddleback Caterpillar: Acharia stimulea

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 caterpillars when you're gardening. Like a lot of stinging caterpillars, they are slug-like and slow. Waiting them to move out of your way is time-consuming, 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.

The Basics

Scientific name: Acharia stimulea

Food Plant: a very wide variety of plants, including maple, dogwood, pecan, and crepe myrtle

Range: Southeastern US

Adult Moth: The adult is small and stout with dark-brown wings

Severity of Sting: This caterpillar has a sharp, painful sting, similar to a honeybee

A Group of Saddleback Caterpillars

Immature saddleback caterpillars tend to feed in groups, while older caterpillars feed singly.

Immature saddleback caterpillars tend to feed in groups, while older caterpillars feed singly.

A Lifetime Chasing Caterpillars

My career as a citizen scientist spans four decades. My paternal grandfather, Arthur Cushman, was an artist who worked for the USDA and The Smithsonian Institution. On occasion he would send me cast-off specimens from the museum collection, and I was a devoted entomologist by the time I was seven years old. As an adult, I have taken my obsession to the next level: I camp alone in jungles and deserts, seeking insects tp photograph, collect, and record; I donate specimens to museums and studies; and as I mentioned above, 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

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, a rich chestnut brown with deep green markings. It's quite well camouflaged, though, so you'll probably never see one in real life.

The Basics

Scientific name: Parasa indetermina

Food Plant: Many pants, including apple, dogwood, hickory, maples, oaks, poplars, and rose bushes.

Range: Southeastern US

Adult Moth: The adult moth has extensive green markings

Severity of Sting: This caterpillar has a nettle-like sting

stinging-caterpillars

The Spiny Oak Slug: Euclea delphinii

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.

The Basics

Scientific name: Euclea delphinii

Food Plant: Many trees and plants, including apple, ash, basswood, beech, birch, blueberry, cherry, chestnut, hackberry, hickory, maple, oak

Range: Across the eastern US

Adult Moth: The adult moth is small to medium sized, with brown and green markings

Severity of Sting: Like the stinging rose caterpillar, the sting of this species is similar to that of a nettle.


This caterpillar has inconspicuous stinging hairs.

This caterpillar has inconspicuous stinging hairs.

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.

The Basics

Scientific name: Norape ovina

Food Plant: Willows and other plants

Range: Across eastern US

Adult Moth: The adult moths are small, inconspicuous moths

Severity of Sting: Tend to occur in groups, which means you often get stung by more than one caterpillar

Monkey Slug

This odd caterpillar hides stinging spines on fleshy appendages.

This odd caterpillar hides stinging spines on fleshy appendages.

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."

The Basics

Scientific name: Phobetron pithecium

Food Plant: Several plants, including apple, ash, birch, cherry, and chestnut

Range: Most of the eastern US

Adult Moth: The day-flying adult moth is small and brown and may mimic a bee.

Severity of Sting: This caterpillar has a sting like a bee.

A Very Cool Video of Stinging Monkey Slug Caterpillars

While not toxic, this caterpillar has extremely sharp and stiff spines.

While not toxic, this caterpillar has extremely sharp and stiff spines.

Giant Leopard Moth Caterpillar: Hypercompe scribonia

This large caterpillar can sometimes be found curled up under stones or logs, where it overwinters. The spines of this species do not contain and toxins, but they are extraordinarily sharp and stiff, and could cause some slight damage if handled carelessly.

The Basics

Scientific name: Hypercompe scribonia

Food Plant: Many low plants, including plantain

Range: Ranges across the US and into Canada; similar species south into Mexico

Adult Moth: The adult moths are large, beautiful insects

Severity of Sting: Does not sting, but the spines are surprisingly stiff and sharp

stinging-caterpillars

Isa textula: Crowned Slug Moth

Another caterpillar in the Limacodidae family, Isa textual is known as the "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.

The Basics

Scientific name: Isa textula

Food Plant: Mostly oaks and maples

Range: Several similar species, ranging across the US and into Canada and Mexico

Adult Moth: The adult moths are small and densely furred

Severity of Sting: Can be painful, comparable to a small bee sting

Io Moth Caterpillar

The io moth caterpillar is large and capable of giving you a very sharp sting.

The io moth caterpillar is large and capable of giving you a very sharp sting.

The Io Giant Silk Moth Caterpillar: Automeris io

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.

The Basics

Scientific name: Automeris io; there are related species across the US

Food Plant: Many plants, including redbud, willow, maple, and ash.

Range: Automeris species range across the US

Adult Moth: Very beautiful moths with striking false eyespots on the hindwings

Severity of Sting: Can be painful; comparable to a bee sting

Another view of the Io moth caterpillar:

stinging-caterpillars

Caterpillar Basics

Caterpillars are the immature form of butterflies and moths. They hatch from eggs laid by a fertilized female, and quickly begin eating and growing. In the cycle of forms that every butterfly and moth undergo (known as "complete metamorphosis"), the caterpillar is the phase that accumulates and stores fat and energy. The adult moth or butterfly eats relatively little; their task is to reproduce and lay fertilized eggs.

The caterpillar will shed its skin several times as it grows. Finally it becomes a pupa, during which time it does not move but changes radically inside the pupal shell. Moth caterpillars spin a cocoon around the pupa. The pupa of a butterfly usually hangs from the food plant and is called a "chrysalis."

Complete metamorphosis occurs in many other kinds of insects, including beetles, bees, cicadas, and dragonflies.

This species is related to the io moth. Its sting can be quite painful.

This species is related to the io moth. Its sting can be quite painful.

Buck Moths; Genus Hemileuca

There are several closely related moths in the genus Hemileuca, and the larvae of all of them can sting. The buck moth species you are most likely to encounter is H. maia, the Eastern buck moth; at times, the caterpillars experience a population explosion, and can appear in large numbers seemingly overnight. At these times, your chances of being stung rise exponentially.

Buck moths are related to the io moth, which also has a number of less-well-known species and sub-species. In general, it's best to be cautious around caterpillars with bright colors and multiple sets of rosette spines.

The Basics

Scientific name: Hemileuca species

Food Plant: Mostly oaks

Range: Several species, ranging across the US and into Canada and Mexico

Adult Moth: The adult moths are large, beautiful insects

Severity of Sting: Can be very painful, especially if you come into contact with a group of the caterpillars.

The white-marked tussock moth caterpillar doesn't sting, but the fur can cause irritation in some people.

The white-marked tussock moth caterpillar doesn't sting, but the fur can cause irritation in some people.

The White-Marked Tussock Moth: Orgyia leucostygma

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.

The Basics

Scientific name: Orgyia leucostigma

Food Plant: Many plants and trees, including ornamentals

Range: Ranges across the US; there are several related species

Adult Moth: The adult moths are small, gray insects; females are wingless

Severity of Sting: Does not sting, but hairs can be irritating

This interesting caterpillar is reportedly able to spray irritating acid from a gland near its head.

This interesting caterpillar is reportedly able to spray irritating acid from a gland near its head.

Variable Oakleaf Caterpillar Lochmaeus manteo

This caterpillar comes in a bewildering array of colors and patterns -- some individuals don't even look like they belong to the same species. There are reports that this insect possesses a gland near the head that can spray formic acid if the caterpillar is disturbed. Formic acid is also used by ants and some other insects for protection, and it can cause a burning sensation. While not dangerous, this unique form of protection makes this caterpillar one to watch out for.

While it is, as the name suggests, quite variable, this description of Lochmaeus manteo from Alabama University is useful:

"The head is greenish with a vertical black stripe on each side, bordered on the outside by a cream to white stripe. The base color of the body is green. There is a narrow yellowish, cream, or white line down the midline of the back, and wider cream or white lines along the edges of the back. Coloration of this back area is highly variable (thus the common name), and ranges from green to reddish brown with gradations between."

The Basics

Scientific name: Lochmaeus manteo

Food Plant: Mostly oaks

Range: Several similar species, ranging across the US and into Canada and Mexico

Adult Moth: The adults are medium-sized, gray-brown moths

Severity of Sting: Does not sting; can emit irritating fluids from near the head

Found in South America, this species is extremely venomous.

Found in South America, this species is extremely venomous.

This South American Caterpillar Can Actually Kill You: Lonomia obliqua

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 obliqua 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!

Resources

The following sources were used in the production of this guide:

https://entomology.ca.uky.edu/ef003

http://enpp.auburn.edu/outreach/web-publications/stinging-caterpillars/

Thanks for Reading!

Raymond James Wagner on November 25, 2019:

I got stung by a catipillar the redness is going to my chest

None ya beeswax on July 21, 2019:

What about a yellow black and purple caterpillars Ive even catching them and handling them with glovesthey have 2 to 3 purple stripes occasionally 1 anyone know?

Grace on July 11, 2019:

Hi, we have many caterpillars in our garden that have soft rows of hairs

along their sides, a few lines along their back and a purple tuft of hair at the end of their back.

Do they sting, or is it safe to handle them?

Thank you.

Chuck Smith on May 31, 2019:

Great pictures The history you attached to each very interesting.

Ray on May 17, 2019:

A green fuzzy Caterpillar landed on my neck a week and a 1/2 ago I knocked it off and and about an hour I had a really badd rash all over my neck and it's been a week and a 1/2 and it is finally starting to go away still itches a little bit.

Virginia Allain from Central Florida on June 04, 2018:

I've seen a few of these in NH. I'll be careful of them in future.

Audrey Rater on August 27, 2016:

I was stung by a caterpillar today. It was a very light and bright green in color. So far, I have not ID'd it.

Birthday Wishes from Here on September 09, 2013:

Very nice lens! I have learned a lot. Thanks a lot for sharing.

anonymous on August 28, 2013:

ive just seen a long grey caterpiller while out walking in a park it had a long bright blue spike at the end, i tried to move it out of the pathway by using a leaf it flipped its body into a u shape trying to sting me, would like to know which caterpiller it is ive just seen, can anyone help me?

mel-kav on August 19, 2013:

Thanks for this informative lens. There are some really strange looking caterpillars.

RANADEEP on August 14, 2013:

Good info but I think there is more out there,right?I will surely check this lense later for your updates!!

OILDALE1 on August 12, 2013:

omg!i didn't know caterpillars can sting!!!good lense...

SusanAston on July 27, 2013:

Nature is wondrous. Thank you for this great lens.

Tom Maybrier on July 09, 2013:

Wow these are bizarre looking! Great lens.

angelinaward lm on July 05, 2013:

This is a great lens! Hairy creatures aren't they!

srsddn lm on January 10, 2013:

Quite interesting and well presented lens.

Related Articles