Hobbies And Interests
Body Plan
Caterpillars have a segmented body plan that consists of its head, with mandibles; its thorax, divided into the thoracic segments, with three pairs of jointed legs that possess hooks also known as true legs, which are designed to hold onto food; an abdomen, divided into abdominal segments, which usually possesses four to five pairs of stumpy prolegs; and the anal prolegs at its back.
Growth Pattern
Caterpillars grow in spurts by shedding skin and expanding to a larger size. The process of a caterpillar's growth is called ecdysis, after the hormone ecdysone that controls molting. Each new stage of its growth is called a new instar. Most species of caterpillars molt four times, and their final stage of growth is their fifth instar.
Locomotion, Breathing and Sight
Caterpillars push blood into their front segments by contracting the muscles in rear segments, lengthening the front of their bodies and creating the characteristic rippling locomotion. The nine pairs of spiracles located along the thorax and abdomen function as breathing pores. Caterpillars possess six pairs of eyes, called ocelli, which are small, basic eyes that are able to detect changes in the intensity of light. They are composed of light-sensitive photosynthetic cells and pigments, and are commonly located in two groups of six eyes on the larva's head.
Silk Production, Touch and Lifespan
Caterpillars are able to produce silk by use of spinnerets, which are tube-like salivary glands. The silk is used to produce their cocoons and to support themselves. They use their small tactile hairs called setae to sense their surroundings. These are located all over the caterpillar's body and grow through holes in the pinaculum, which are small flat, dark plates on the caterpillar's exoskeleton. In general, caterpillars live between two weeks and a month -- often the longest part of the butterfly or moth's life cycle.