Caterpillars, butterfly larvae, and moths come in a variety of shapes and sizes. Although most are harmless, stinging caterpillars let you know that they don’t like to be touched. Stinging caterpillars have the same defense strategy to deter predators. They all have stinging hairs, thorns, or barbed wire—each hollow fungus channels venom from a particular glandular cell. The spines stick to your finger, then pass through the caterpillar’s body and release toxins into its skin.
What happens if you touch a stinging caterpillar? It hurts! You will feel a slight sting, itching, or burning. You may get a rash, even pustules or unpleasant lesions. In some cases, the area may become larger or numb, or you may feel nauseated and vomit. Itchy caterpillars are very serious. Below we’ve jotted down 10 caterpillars you should not touch!
#1. Crowned Slug Caterpillar
Here is a beauty of a caterpillar. The crowned slug shows its spines like the feathered helmet of a Las Vegas showgirl. The stinging mushroom line perimeter of the crowned slug, decorating its flattened, green body. Later instars may also be marked with colored red or yellow dots along the caterpillar’s back.
#2. Io Moth Caterpillar
With many-branched spines full of venom, this io moth caterpillar is ready for a fight. The eggs are laid in groups so that the first instar caterpillars will be seen in clusters. Larvae start life dark brown, gradually molting from brown to orange, then tan, and finally to this green color.
#3. Hag Moth Caterpillar
The hag moth caterpillar bite is sometimes called the monkey slug, which seems appropriate when you see what it looks like. It’s hard to believe it’s still a caterpillar, frankly. The monkey slug is instantly recognizable by its hairy “arms” that sometimes fall off. But beware, this adorable caterpillar is tiny and covered with stinging hairs.
#4. The Caterpillar Cat
This pus caterpillar looks like it could reach out and pet it, but appearances are deceptive. Beneath that long, blond hair, poisonous bristles hide. Even shedding skin can cause a serious skin reaction, so don’t touch anything that looks like this caterpillar. At its largest, the pus caterpillar grows to a single inch long. The Cat caterpillars are the larvae of the southern flannel moth.
#5. Prickly Elm Caterpillar
Although most stinging caterpillars turn into moths, this spiny larva will be a magnificent mourning moth one day. Spiny elm caterpillars usually live and forage in groups.
#6. Rose Caterpillar Bite
The bite rose caterpillar does precisely that – it stings. The color can vary from yellow to red with this caterpillar. Look for the unique pinstripes to identify four dark stripes along the back, with cream-colored stripes between them.
#7. Spread Dagger Moth Caterpillar
Here’s another stinging caterpillar that varies in color. Look for yellow spots along each side and raised red bumps on the back. The dagger-spotted moth caterpillar also goes by the caterpillar named smartweed, for one of its preferred host plants.
#8. Buck Moth Caterpillar
These black and white caterpillars use branching spines to defend themselves against predators. Like the io moth caterpillars, these buck moth caterpillars live gregariously in their early stages. David L. Wagner, the author of Eastern North America Caterpillars, points out that a bite he received from a money moth caterpillar was still visible ten days later, with bleeding where the spines had penetrated the skin.
#9. Spiny Oak Slug Caterpillar
The spiny oak slug comes in a rainbow of colors; it turns green. Even if you do find a rose, it can be recognized by the four darkest groups of thorns near the rear end.
#10. White Spot Caterpillar Tuft Moth
The caterpillar tuft of the white-marked moth is easy to identify. Note the redhead, black back, and yellow stripes on the sides, and you will be able to recognize this caterpillar from stinging. Many caterpillars of the tuft moth, including this one, are considered forest pests because of their voracious and indiscriminate taste for woody plants.