Do Caterpillars Bite or Sting?

Caterpillars, the larvae of butterflies and moths, come in many shapes and sizes. Though most are harmless, the stinging caterpillars let you know they don't like to be touched.

Stinging caterpillars share a common defensive strategy to dissuade predators. All have urticating setae, which are barbed spines or hairs. Each hollow setae funnels poison from a special glandular cell. The spines stick in your finger, then break away from the caterpillar's body and release the toxins into your skin.

When you touch a stinging caterpillar, it hurts. The reaction depends on the caterpillar, the severity of the contact, and the person's own immune system. You'll feel some stinging, itching, or burning. You might get a rash, or even some nasty pustules or lesions. In some cases, the area will swell or become numb, or you'll get nauseated and vomit.

National Capitol Poison Center recommends using tape to remove a caterpillar and any hairs or spines from your skin once you've been exposed to avoid more contact with skin. Then wash gently with soap and water and apply baking soda and water paste or a hydrocortisone cream or antihistamine cream (if you aren't allergic.) If the condition is worse, see a doctor.

Stinging caterpillars mean business. Here are some nice, safe pictures to view, so you know what they look like.

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Saddleback Caterpillar

Though the bright green "saddle" makes you want to take a closer look at the saddleback caterpillar, don't be tempted to pick it up. The saddleback's spines protrude in nearly every direction. The caterpillar will arch its back to get as many spines into you as possible. The young caterpillars feed together in a group, but as they get larger they begin to disperse.

Species and Group

Sibine stimulea. Slug Caterpillars (Family Limacodidae)

Where It's Found

Fields, forests, and gardens from Texas to Florida, and north to Missouri and Massachusetts.

What It Eats

Just about anything: grasses, shrubs, trees, and even garden plants.

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Crowned Slug Caterpillar

Crowned slug caterpillar. Flickr user ()

Here's a beauty of a caterpillar. The crowned slug displays its spines like the feathered headpiece of a Vegas showgirl. The stinging setae line the crowned slug's perimeter, decorating its flattened, green body. Later instars (or phases between development) may also be marked with colorful red or yellow spots along the caterpillar's back.

Species and Group

Isa textula. Slug Caterpillars (Family Limacodidae)

Where It's Found

Woodlands, from Florida to Mississippi, north all the way to Minnesota, southern Ontario, and Massachusetts.

What It Eats

Mostly oak, but also elm, hickory, maple, and a few other woody plants.

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Io Moth Caterpillar

Io moth caterpillar. Getty Images/jamesbenet

With many-branched spines full of poison, this io moth caterpillar is ready for a fight. Eggs are laid in clusters, so earliest instar caterpillars will be seen in bunches. They start larval life a dark brown, and gradually molt from brown to orange, then tan, and finally to this green color.

Species and Group

Automeris io. Giant Silkworm and Royal Moths (Family Saturniidae).

Where It's Found

Fields and forests from southern Canada all the way to Florida and Texas

What It Eats

Quite a variety: sassafras, willow, aspen, cherry, elm, hackberry, poplar, and other trees; also clover, grasses, and other herbaceous plants

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Hag Moth Caterpillar

Hag moth caterpillar. Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org

The stinging hag moth caterpillar is sometimes called the monkey slug, which seems a suitable name when you see what it looks like. It's hard to believe this is even a caterpillar. The monkey slug can be identified instantly by its furry-looking "arms," which sometimes fall off. But beware: This cuddly caterpillar is really covered in tiny stinging setae.

Species and Group

Phobetron pithecium. Slug Caterpillars (Family Limacodidae).

Where It's Found

Fields and forests, from Florida to Arkansas, and north to Quebec and Maine.

What It Eats

Apple, cherry, persimmon, walnut, chestnut, hickory, oak, willow, birch, and other woody trees and shrubs.

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Puss Caterpillar

Flannel moth or puss caterpillar. Getty Images/Paul Starosta

This puss caterpillar looks like you could reach out and pet it, but looks can be deceiving. Underneath that long, blond hair, venomous bristles hide. Even a molted skin can cause a serious skin reaction, so don't touch anything that looks like this caterpillar. At its largest, the puss caterpillar grows to just one inch long. Puss caterpillars are larvae of the southern flannel moth.

Species and Group

Megalopyge opercularis. Flannel Moths (Family Megalopygidae).

Where It's Found

Forests from Maryland south to Florida, and west to Texas.

What It Eats

Leaves of many woody plants, including apple, birch, hackberry, oak, persimmon, almond, and pecan.

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Spiny Elm Caterpillar

Spiny elm caterpillar. Steven Katovich, USDA Forest Service, Bugwood.org

Though most stinging caterpillars become moths, this prickly larva will one day be a beautiful mourning cloak butterfly. Spiny elm caterpillars live and feed in groups.

Species and Group

Nymphalis antiopa. Brush-Footed Butterflies (Family Nymphalidae).

Where It's Found

Wetlands, forest edges, and even city parks from northern Florida over to Texas, and north well into Canada.

What It Eats:

Elm, birch, hackberry, willow, and poplar.

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White Flannel Moth Caterpillar

White flannel moth caterpillar. Lacy L. Hyche, Auburn University, Bugwood.org

The white flannel moth caterpillar feels like anything but flannel—it's prickly. Look closely, and you'll see long hairs extending from its sides. Clumps of shorter, stinging spines line its back and sides. The adult moth is white, as the name suggests, but this larva wears a color scheme of black, yellow, and orange.

Species and Group

Norape ovina. Flannel Moths (Family Megalopygidae).

Where It's Found

Fields and forests from Virginia to Missouri, and south to Florida and Texas.

What It Eats

Redbud, hackberry, elm, black locust, oak, and some other woody plants. Also greenbrier.

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Stinging Rose Caterpillar

Stinging rose caterpillar. Getty Images/John Macgregor

The stinging rose caterpillar does just that—it stings. The color may vary from yellow to red with this caterpillar. Look for the unique pinstripes to identify it: four dark stripes along the back, with cream-colored stripes between them.

Species and Group

Parasa indetermina. Slug Caterpillars (Family Limacodidae).

Where It's Found

In barrens and scrubby coastland areas, stretching from Illinois to New York, and south to Texas and Florida.

What It Eats

A good variety of woody plants. Including dogwood, maple, oak, cherry, apple, poplar, and hickory.

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Nason's Slug Caterpillar

Nason's slug caterpillar. Lacy L. Hyche, Auburn University, Bugwood.org

Nason's slugs don't sport the biggest spines in the stinging caterpillar world, but they can still pack a mild punch. These small spines retract, but if the Nason's slug feels threatened, it can quickly extend the poisonous barbs. If you look at the caterpillar head-on, you'll notice its body is a trapezoidal shape (not obvious in this photo.)

Species and Group

Natada nasoni. Slug Caterpillars (Family Limacodidae).

Where It's Found

Forests from Florida to Mississippi, north to Missouri and New York.

What It Eats

Hornbeam, oak, chestnut, beech, hickory, and some other trees.

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Smeared Dagger Moth Caterpillar

Smeared dagger moth caterpillar. Flickr user Katja Schulz (CC by SA)

Here's another stinging caterpillar that varies in color. Look for the yellow patches along each side, and raised red spots on its back. The smeared dagger moth caterpillar also goes by the name smartweed caterpillar, for one of its preferred host plants.

Species and Group

Acronicta oblinita. Owlets, Cutworms, and Underwings (Family Noctuidae).

Where It's Found

Beaches, marshes, and barrens, with a range stretching from Florida and Texas all the way to southern Canada.

What It Eats

Broad-leaved herbaceous plants, as well as some woody trees and shrubs.

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Buck Moth Caterpillar

Buck moth caterpillar. Susan Ellis, Bugwood.org

These black and white caterpillars use branching spines to fend off predators. Like the io moth caterpillars, these buck moth caterpillars live gregariously in their early instars. David L. Wagner, author of Caterpillars of Eastern North America, notes that a sting he received from a buck moth caterpillar was still visible 10 days later, with hemorrhages at the sites where spines had penetrated his skin.

Species and Group

Hemileuca maia. Giant Silkworm and Royal Moths (Family Saturniidae).

Where It's Found

Oak forests from Florida to Louisiana, north through Missouri and all the way to Maine.

What It Eats

Oak in early instars; older caterpillars will chew on most any woody plant.

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Spiny Oak Slug Caterpillar

Spiny oak slug caterpillar. Wikimedia Commons/GothMoths (CC by SA)

The spiny oak slug comes in a rainbow of colors; this one happens to be green. Even if you find a pink one, you can recognize it by the four clusters of darker spines near the hind end.

Species and Group

Euclea delphinii. Slug Caterpillars (Family Limacodidae).

Where It's Found

Woodlands from southern Quebec to Maine, and south through Missouri to Texas and Florida.

What It Eats

Sycamore, willow, ash, oak, hackberry, chestnut, as well as many other trees and smaller woody plants.

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White Marked Tussock Moth Caterpillar

White marked tussock moth caterpillar. Getty Images/Kitchin and Hurst

The white-marked tussock moth caterpillar is easy to identify. Note the red head, black back, and yellow stripes down the sides, and you'll be able to recognize this stinging caterpillar. Many tussock moth caterpillars, including this one, are considered tree pests due to their ravenous and undiscriminating taste for woody plants.

Species and Group

Orgyia leucostigma. Tussock Caterpillars (Family Lymantriidae).

Where It's Found

Forests from southern Canada to Florida and Texas.

What It Eats

Just about any tree, both deciduous and evergreen.

Sources

“Stinging Caterpillars.” Auburn University Entomology and Plant Pathology.
Wagner, David L. Caterpillars of Eastern North America: A Guide to Identification and Natural History. Princeton University Press, 2005, Princeton, N.J.

13 Stinging Caterpillars

Saddleback Caterpillar

Species and Group

Where It's Found

What It Eats

Crowned Slug Caterpillar

Species and Group

Where It's Found

What It Eats

Io Moth Caterpillar

Species and Group

Where It's Found

What It Eats

Hag Moth Caterpillar

Species and Group

Where It's Found

What It Eats

Puss Caterpillar

Species and Group

Where It's Found

What It Eats

Spiny Elm Caterpillar

Species and Group

Where It's Found

What It Eats:

White Flannel Moth Caterpillar

Species and Group

Where It's Found

What It Eats

Stinging Rose Caterpillar

Species and Group

Where It's Found

What It Eats

Nason's Slug Caterpillar

Species and Group

Where It's Found

What It Eats

Smeared Dagger Moth Caterpillar

Species and Group

Where It's Found

What It Eats

Buck Moth Caterpillar

Species and Group

Where It's Found

What It Eats

Spiny Oak Slug Caterpillar

Species and Group

Where It's Found

What It Eats

White Marked Tussock Moth Caterpillar

Species and Group

Where It's Found

What It Eats

Sources

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