Caterpillars have soft bodies that can grow rapidly between moults. Their size varies between species and instars, from as small as 0.04 inch up to 5.5 inches.
Varies with the species. Some caterpillars can change colour as camouflage for defence.
Butterflies and moths spend their childhood as caterpillars, called the larval stage. They are members of the order Lepidoptera.
Caterpillars of most species are herbivorous and have been called “eating machines”, eating leaves voraciously. Many of them are among the most serious of agricultural pests. They are restricted to feeding on one species of plant, while others are polyphagous. Some (about 1%) are insectivorous, even cannibalistic. Some feed on other animal products; for example, clothes moths feed on wool and moths feed on the hooves and horns of dead ungulates. Many caterpillars are nocturnal. For example, cutworms hide at the base of plants during the day and only feed at night.
Most species shed their skin four or five times as their bodies grow and they eventually enter a pupal stage before becoming adults. Caterpillars grow very quickly; for instance, a tobacco hornworm will increase its weight ten thousand-fold in less than twenty days.
You can find caterpillars almost everywhere from sandy beaches to meadows to mountain forests, worldwide. There are even caterpillars in some Arctic areas.
The majority of caterpillars are herbivores and present in vegetated areas. They eat mostly leaves, though some species eat all plant parts, fungi and dead animal matter, including other caterpillars.
Tips for Control
Caterpillar hair can be a cause of human health problems. Caterpillar hairs sometimes have venoms in them and can inflict serious human injuries. Skin rashes are the most common, but there have been fatalities. The sharp barbs on the end of caterpillar hairs can get lodged in soft human tissues and mucous membranes such as the eyes. Once they enter such tissues, they can be difficult to extract, often exacerbating the problem as they migrate across the membrane.
This becomes a particular problem in an indoor setting. The hair easily enters buildings through ventilation systems and accumulate in indoor environments, because of their small size, which makes it difficult for them to be vented out. This accumulation increases the risk of human contact in indoor environments.
Find out what kind of caterpillars you have. Visit your library, bookstore or search online to be sure what type you are dealing with.
If you only have a few caterpillars here and there and you know what kind they are, pick them off your plants by hand and put them in a bag. If you have an infestation of pest caterpillars too numerous to pick by hand (bagworms and leaf rollers), take stronger action are call a pest control professional.
Before spraying any insect control product, always read the label to be sure your pest and plant are listed.