Butterflies begin as eggs, transform into a larvae or caterpillar stage, then a pupa, and finally a winged adult. Adult females are careful to lay their eggs on plants where they know the caterpillar can feed. This is called a host plant. Caterpillars eat from a menu of host plants including trees, plants, flowers, and shrubs. Caterpillars usually feed on the leaves of host plants. Some caterpillars are picky and like only certain plants. For example, the Karner blue butterfly caterpillar likes to eat lupine.
Adult butterflies eat mostly nectar. A few butterflies don't eat anything during their adult stage of life.
Once caterpillars are finished munching on the host plant, they molt and form a chrysalis, also known as a pupa. While inside the chrysalis, the caterpillar changes into a winged adult. This is called metamorphosis.
The chrysalis is a hard casing made of skin. It can hang down from a branch or stand upright. You'll have to look carefully to find a chrysalis. They sometimes look like a leaf, stem, thorn, or piece of wood. This camouflage helps protect them. As they form into the winged butterfly, look closely and you might be able to see their wings from the outside of the chrysalis.
Once the winged adult breaks out of the chrysalis, it may travel long distances like the monarch butterfly. Some adults simply live long enough to mate, lay their eggs on a host plant and then die. Then the life cycle starts all over.