Caterpillar – Anatomy

Caterpillars come in a wide variety of colors, shapes, and sizes. Some are quite hairy, while others have smooth bodies. Despite these differences, all caterpillars share certain key morphological features. Their segmented bodies consist of a head, a thorax (with three pairs of jointed legs equipped with hooks), and an abdomen (typically with five pairs of legs). The head contains the eyes, mouthparts, small antennae, and spinnerets, which produce silk. Caterpillars have six pairs of simple eyes that can detect changes in light intensity but cannot form clear images. The maxillae contain taste cells that help the caterpillar identify suitable food, prompting it to eat when appropriate. Near the mouthparts, the small antennae detect smells. The legs are primarily used to hold and manipulate leaves for feeding. However, not all caterpillars have the same leg distribution. Caterpillars breathe through oval spiracles that open and close to allow gas exchange with the atmosphere. Each body segment typically has two spiracles, one on each side, to facilitate breathing.