Caterpillar Advice for Parents

Mom, he followed me home! Or, what to do when your child brings home a caterpillar to raise.
Children frequently bring home creatures of all sorts and expect their parent to be able to magically care for them. Tragically, most of these creatures end up dead. This is frequently true for caterpillars, but can perhaps be avoided with a few pointers.
1. Some caterpillars have stinging hairs and are painful or cause itchy rashes if handled. Be wary of handling the fuzzy, spiky ones unless you have identified them.
2. There are many ways to identify your caterpillar. “Caterpillars of Eastern North America” by David Wagner is especially good. www.bugguide.net is also a great resource.
3. Most caterpillars are very picky about their food, and will only eat leaves off of one or just a few “host” plants. These are almost always native plants, and may be trees, weeds, grasses, low growing plants, etc. They cannot be coaxed into eating the lettuce from your refrigerator.
4. Because the caterpillar is a picky eater, it is very important to take note of where it was found. Identify the plant it was taken from, or those plants around where it was crawling. You may need to offer it a “mixed salad” of leaves from that area and take note of what it eats for the next time you have to gather leaves. You must continue to feed it the same kind of leaves until it pupates (becomes a chrysalis or cocoon). You also must make sure that the leaves come from somewhere with no insecticides.
5. Caterpillars eat a lot. They also poop a lot; their poop is called “frass”. Depending on the age and size of your caterpillar, you may be gathering a lot of leaves, and cleaning the enclosure more than daily to keep it clean. The leaves need to be fresh; putting them on a damp paper towel will work for a day, especially if the caterpillar is very small. Poking a twig with several leaves on it into a water vessel with a really tight top (such as a water bottle with a hole in the lid) will keep the leaves fresh longer while also preventing the caterpillar from drowning. This works well when the caterpillar is larger.
6. Caterpillars like to wander. You must keep your caterpillar in an enclosure that is well sealed but allows air flow. If it is small, a Tupperware with holes in the lid works well. When the caterpillar becomes larger, a mesh enclosure such as are sold as “butterfly houses” works, or a small terrarium with netting over the top. Keep your pets away from your caterpillar, and don't allow the children to handle it directly if you want your caterpillar to survive to adulthood.
7. If kept inside the house, the dry air from air conditioning will dry out the leaves and the caterpillar; either keep the enclosure outside or mist it frequently. But beware; if you mist it too often, mold will grow and the caterpillar will die.
8. Caterpillars molt – shed their skin – five times between hatching and pupating; when they are about to molt, they go through a time when they stay very still and can appear dead. Do not bother them during this time as you can easily harm them. They have to molt in order to grow, since their skeleton, like that of all insects, is on the outside and cannot expand; each time they molt they will not only get larger but will often change appearance slightly, changing color a bit or becoming more or less hairy.
9. When your caterpillar gets large – often several inches, but size depends on the species, you need to provide it a place to make a chrysalis. Put in some sticks, some leaf litter and consider a small tub with loose dirt (some caterpillars, particularly hornworms, burrow in the ground to pupate). It is easier to know what you need to put in if you have identified the caterpillar.

An example of a relatively easy caterpillar to raise is the yellow bear caterpillar, a frequent denizen of gardens in the southeast. It will eat a wide variety of plants, is relatively sturdy to be handled, and will cocoon in any enclosure. It emerges in the spring as the Virginia tiger moth.

A monarch caterpillar is of intermediate difficulty – everyone knows they eat milkweed, so that part is easy, but one mature caterpillar can strip a milkweed plant before it is ready to form a chrysalis. Keeping it fed can be a real chore!

Finally, the third is an example of a difficult caterpillar to raise, the silver-spotted skipper, who spends its days wrapped within a structure of leaves of its host plant, Amorpha fruticosa. Providing it with sufficient host plant not only to eat but to form its leaf structure would not be easy.

If this is sounding like a lot of work, it is. It would be much better for the caterpillar to take it back to where your child found it and release it back into the wild. Explain that it needs to be with its family, eating its healthy, natural foods and to grow up in a normal, healthy environment.
After all, butterflies should be free!