Caterpillars in Your Garden!

Lepidoptera is the second largest class of insects, consisting of butterflies and moths. Caterpillars are the larval form of butterflies and moths, which is the stage they are in before undergoing metamorphosis.

Caterpillars are often looked at as agriculture pests. They have an extremely ravenous diet, which makes them want to eat anything and everything in sight. This could mean great danger for the flowers, food, and other plants in your garden.

Anatomy

Caterpillars are made up of three body parts: the head, the thorax, and the abdomen. They have six legs that stem from their thorax. These are jointed legs with hooks that are used to pick up their food. Caterpillars also have prolegs, stumpy little bits that come out of the abdomen to help them climb, especially on vertical surfaces. These are not considered to be true legs.

Caterpillars breathe through their spiracles, which are small openings on the sides of their thorax and abdomen. A few types of caterpillars are even considered to be aquatic because they possess gills, which allow them to breathe underwater.

Humans are made up of 629 muscles, while caterpillars have more than six times that amount, at 4,000. They have 248 muscles just in their head.

Senses

Caterpillars lack a good sense of vision. Instead of actual eyes, they have six stemmata (small eyelets) on each side of their head. With these, the resolution of images is compromised. As for hearing, some caterpillars can pick up vibrations if they are at a specific frequency, but it's unclear how well they can hear sounds.

Classification

Caterpillars' bodies are constantly changing between moults. Their bodies are soft with the exception of their head, making these changes possible. Caterpillars also have hard mandibles for chewing leaves, and behind that are the spinnerets, where they extrude their silk from.

Defenses

Caterpillars have a very high protein content, and this makes them an easy target for other animals to feed on. To protect themselves against other animals, they have developed various defenses. Some have bristles that can irritate the skin of predators, and a few even have urticating hairs, stinging barbs connected to venom glands. To escape their predators, caterpillars have also been known to use their silk to drop from where they are located for a quick escape.

Appearance

A caterpillar's appearance plays a key role in defending itself. Caterpillars' coloring often resembles the plants that they feed on to act as camouflage for when predators are near. Sometimes, they will even have aspects of plants as part of their appearance, such as thorns.

Behavior

Caterpillars have a gigantic appetite. Their bodies grow quickly, and they frequently shed their skin. Most caterpillars are herbivores, which means they only eat plants. Some eat only one specific type of plant, while others can eat many different kinds. Some of the more aggressive caterpillars eat the eggs of other insects. Most caterpillars are nocturnal, hiding out in plants during the day and going out to feed at night.

Economic Effects

Caterpillars can be a danger to agriculture because they tend to feed on the leaves of plants. Many people involved in gardening have made caterpillars a primary focus of pest control efforts. Techniques such as pesticides, biological control, and agronomic practices have all been tried to eliminate them from getting into and destroying crops. Over the years, many caterpillars have become resistant to pesticides, making them ineffective.

Human Health

The hair on caterpillars can actually be a health risk for humans. Some caterpillars have hair that contains dangerous venom that can cause a wide variety of injuries including dermatitis, asthma, renal failure, and hemorrhaging. While skin rashes are the most common injury, there have been fatalities caused by caterpillars. However, this extreme reaction is very rare.

Additional Resources on Caterpillars

Written By Ava Rose.