The monarch butterfly might be the most recognizable insect in the United States, but this is just the final stage of its four-part life cycle. Like all butterflies, monarchs undergo a series of transformations during their lives called metamorphosis. Monarchs start as eggs, and the eggs hatch into caterpillars, which is the larval stage of their life cycle. After a few weeks, the caterpillar will enter a chrysalis, where it transforms and then emerges as a butterfly.
Throughout their lives, monarchs are very dependent on milkweed plants. These plants are the host plants for monarchs. The butterflies only lay eggs on milkweed, and the caterpillars only eat milkweed. Without milkweed, there would be no monarchs.