Butterfly Larva (Caterpillar)
Larva, also known as a caterpillar, is the stage of the butterfly’s life cycle for growth. The larva spends its time eating, growing, and resting. The caterpillars feed on their host plants, which can range from a single species to many different species.
As caterpillars grow, they shed their exoskeleton, because the skin does not grow with the caterpillar. The exoskeleton is their support and protective structure on outside of their body. This process is called molting. Each stage between molts is called an instar. Caterpillars usually have five instars before pupating.
Caterpillars have evolved to have some interesting techniques to protect themselves. A common characteristic is camouflaging. Many caterpillars resemble plant parts, bird droppings, or may just look frightening to scare off predators. An example is many of the swallowtail caterpillars. Early in their life, they resemble bird droppings, and as they grow larger, their color changes to they develop huge ‘eye spots’ on their thorax regions so that they appear snake-like.
Swallowtail caterpillars also have an osmeterium, which is an interesting looking defensive organ that protrudes out from above their head when threatened, producing a smelly scent.
A few caterpillars are brightly colored and they usually are able to save plant toxin in their bodies, making them poisonous to predators. They may be able to mimic other poisonous caterpillars while being completely harmless, or may be covered in body hairs – some have stinging body hairs to prevent getting eaten. As the caterpillar reaches the final instar, the wing pads have already been formed. This is why you can see the shape of the wings on the chrysalis.
As the caterpillar reaches the final instar, the wing pads have already been formed. This is why you can see the shape of the wings on the chrysalis.