Caterpillars' Diet

All caterpillars turn into butterflies or moths, but in order to reach that pinnacle of development, the caterpillar must strengthen itself by eating, so it can survive the cocoon stage of its development. Because of their voracious appetites, caterpillars are considered by some to be pests capable of major crop and plant devastation.

Diet

Most caterpillars are herbivorous, which means they only eat plants. Leaves tend to be the most popular part of the plant for most caterpillars but some will eat flowers and berries as well. Some species even restrict themselves to one particular species of plant or another. In cases such these, the caterpillars sometimes choose to lay their eggs on the leaves of plants they spent their lives devouring. Other caterpillars are more predatory and choose to eat the eggs or larvae of other insects. And in rarer cases, caterpillars are known to eat others of their own species.

Behavior

Caterpillars are built to eat and because of this, their bodies grow at an amazing rate. Most caterpillars shed their skin four or five times during their life to accommodate their growing mass. In one amazing instance, the tobacco hornworm increases its weight 10,000 fold in just around 20 days. Caterpillars have very poor eyesight and rely on side to side head movement and short antennae to find potential food and potential dangers. They also tend to be nocturnal, sleeping at the base of their chosen plant and emerging at night to eat.

Defense Mechanisms

This caterpillar uses camouflage as a defense.

Because caterpillars are fairly slow moving and very rich in protein, they can be a very easy and desirable prey. On the most basic level, their markings and coloring serve to confuse or dissuade potential predators. Some caterpillars are the same color as the plants on which they feast making them practically invisible. On the flip side, some are so brightly colored that they are easily visible but predators assume them to be poisonous. Others have protruding but harmless hairs that resemble thorns of the plant on which they're feeding and others are made to resemble other natural but undesirable elements in the environment such as bird poop or twigs. In addition, caterpillars are known to hide underneath and between other leaves as they eat. Some spin silk nets around themselves to create a barrier between them and the outside world.

Some caterpillars have more proactive defense mechanisms such as poisonous or detachable, irritating hairs. In a strange twist, particular plants have developed poisons meant as a defense against the caterpillars and other plant eating insects. The caterpillars have adapted to these poisons so that they can not only still eat the plants, but can internalize the plant's poison which then becomes very detrimental to any predator trying to, in turn, eat the caterpillar.

Other caterpillars actually regurgitate acid onto attackers and some simply attach a silk line their leaf and drop to the ground to avoid dangerous situations.

Caterpillars as Pests

A colony of tent worms

Caterpillars remain caterpillars for two to four weeks. Considering the amount and rate at which they eat, they can cause massive destruction to crops and trees. Because of this, pesticides and other chemical warfare have been developed to try and eradicate the problem, but caterpillars evolve at a very rapid pace and quickly become resistant to chemicals used against them. Larger infestations of caterpillars such as tent worms are sometime dealt with by simple removal. The branches on which the caterpillars have made their home are cut from the tree and removed along with the caterpillars.

Benefits

While most view caterpillars as pests, they all eventually turn into butterflies. Besides being beautiful, butterflies help pollinate plants and are a very important part of our ecosystem.

Silk worms bred and farmed for their silk in places such as China, Korea, Russia and Japan. The silk gathered from these caterpillars makes beautiful fabrics and garments and is an important economic element in these countries.

Some types of caterpillars are also enjoyed as food. Silk worms are a common snack food in China and Japan and in Southern Africa, a particular kind of caterpillar, the mopani, is an important source of protein.

References

• Backyardnature.net: Caterpillar
• University of Arizona Center for Insect Science: Silkworm Information