Question: Which caterpillars can sting me?
Answer: I will start by saying that unless you are 100% certain you know the insect you are seeing is safe to touch, you should not pick it up with your bare hands and expect leave the encounter unharmed. You should not be fearful of caterpillars, but always use caution when you encounter a species with horns or hairs. Most stings produced by these larvae are mild and symptoms go away quickly.
Caterpillars are the larval form of insects in the order Lepidoptera.
There are several thousand species of caterpillars in the Eastern United States and it is estimated that they make up around 10% of the existing described species in the world.
These insects are usually described as having an easily distinguished head and 13 body segments, which have six legs in the front and most of the time have fleshy false legs in the back (the number of these can vary). They come in a huge variety of colors, shapes, and sizes, but the caterpillars I want to talk about today are the most feared – the ones that sting!
Caterpillars that sting are not using the same apparatus as a bee or ant that stings. Caterpillars that can sting have hollow projections called setae that grow from poisonous glands on their skin. People usually say these caterpillars look “hairy” or “spiky”. Not all caterpillars with setae are venomous, and some are simply trying to appear like a similar more dangerous species. This can make differentiating them a little difficult. Stinging caterpillars do not actively try to sting predators; but when they are touched, their hairy setae break off on the attacker and the poison is released.
The most common family of stinging caterpillars in Alabama are the slug caterpillars. This family includes the saddleback caterpillar, the stinging rose caterpillar, the hag moth caterpillar, and the spiny oak slug. Most of these caterpillars are solitary and can be found from summer to late fall. Almost all the caterpillars in this family have large, easy-to-see projections that bear setae. They are often brightly colored and look quite unique. The saddleback’s sting is the most painful of this group, while the others are described as being relatively mild.
Another group of stinging caterpillars is the giant silkworm. In Alabama, we often see the Io moth caterpillar and the buck moth. Both of these bear short spiny setae all over their bodies and they are some of the largest stinging caterpillars in the state.
The puss caterpillar is another common stinging larvae. It has a unique appearance, in that it is covered in a coat of long fine tan hairs. This furry creature can produce severe reactions (some have required medical attention) and has a fairly wide variety of hosts. Though petting this larvae may seem tempting, stay away!
There are several common species of caterpillars in the state that look dangerous, but are completely harmless to humans. The hickory horned devil, spiny oak worm, and hornworms all have spiky looking horns that can be scary to see, but are not venomous. There are also several hairy species, namely the walnut caterpillar, fall webworm, and sycamore tussock, which are also harmless and commonly found.
I hope that this information can be helpful to you in differentiating between the stinging and non-stinging caterpillars of Alabama, and if you are ever in doubt, don’t touch!
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