The Wonderous Caterpillar (Science sains)

Caterpillar colors and body shapes are as diverse as the butterflies that they will eventually become. They range from small brown almost maggot-like larvas to huge, fat, alien-like creatures that can reach over 4 inches in length.

The anatomy of a caterpillar is comprised of jointed body segments like that of the common earthworm. They have three sets of legs (true legs) used for walking and also posses fleshly appendages called pro-legs that end in tiny hooks that allow them to grasp the edges of leaves. Like all other butterfly catepillars, beathing is accomplished by intaking air through small openings located between segments of the catepillars body. They have the highest number of muscles in their small body of any animal on the planet. Comparative studies show that humans only have 792 distinct muscles, whereas grasshoppers have 900, and caterpillars may have as many as 4,000 separate muscles.

Most are vegetarians and usually eat only a small number of plants called their host plants where they will later after metamorphosis lay eggs as an adult butterfly if female. Caterpillars are voracious eaters. One species, the Polyphemus larva, also the worlds largest at nearly 4 inches in length, can eat over 86,000 times its body weight in less than 2 months before pupating. They have strong jaws and eat leaves in a top-down fashion usually going from left to right along the leaf edge and working its way down to the stem.

Not the push-overs that they would seem to be adult caterpillars have an arsenal to help protect them from preditors. Some have poisonous spike-like appendages on the top of their segments that when touched produce a irritating toxin that can cause major irritation of the skin when handled. Others rely on the production of toxins built-up from the plants that they consume to dissuade enemies from eating them. The toxins, although not usually fatal, will give pause to birds that are thinking of eating another of the species after their first experience. Members of the swallowtail family have another weapon at their disposal. Theses caterpillars posses two long horn like structures, called an Osmeterium that they can extend from the top of the head that emit a noxious odor that gives the impression to preditors that they will get a very bad taste in their mouth if they try for a quick snack.

Some moths and butterflies remain caterpillars for two or three months, others for about 10 months, hibernating through the winter in this stage. In the Arctic are some forms that require two or three years to develop from egg to adult.

by Tim Willbanks