Magnificent Monarch Caterpillar Eating Upside Down Stock Image

The monarch butterfly or simply monarch Danaus plexippus is a milkweed butterfly subfamily Danainae in the family Nymphalidae. Their host plant is the common milkweed. The caterpillar goes through five major, distinct stages of growth and after each one, it molts. Each caterpillar, or instar, that molts is larger than the previous as it eats and stores energy in the form of fat and nutrients to carry it through the nonfeeding pupal stage. Each instar usually lasts about 3 to 5 days, depending on various factors such as temperature and food availability.