" " An insect goes through a lot before becoming the beautiful butterfly you see fluttering by. The butterfly life cycle is one of the most dramatic transformations in the animal kingdom. Called complete metamorphosis, this process reshapes the insect's entire body structure across four stages. AdvertisementEach stage has its own function, from eating machines to flying adults. And while many species of butterflies follow the same pattern, details can vary depending on the environment, host plant and even time of year.