Young insects develop in two main ways. In some species, such as grasshoppers and locusts, the young that hatch from eggs look rather like small adults, and are called nymphs. As they grow, the nymphs shed their skins, looking more and more like adults each time.
Other insects, such as butterflies, bees and beetles, go through a process called metamorphosis. Their eggs hatch into larvae or caterpillars. Later these become a pupa or chrysalis, within which an imago, or adult insect, develops. The larvae may live in a different habitat from the adult and require different foods.
All insects start their life cycle as eggs after which there are two different life cycles that can take place dependent on the insect species. The main difference between the two life cycles is the development of a pupa or complete metamorphosis. One life cycle is called Hemimetabolous and only has three stages, the other type of life cycle is Holometabolous and has four stages. Most insect life cycles have four distinctive stages which can be observed just by looking at the physical condition of the insect.
Hemimetabolous life cycles have three stages – egg, nymph then adult – which form the adult insect out of an incomplete metamorphosis. The nymph hatches out of the egg and feeds on plants or roots underground for an extended period of time. As the nymph grows, it sheds its skin, and in the final growth stage, the skin sheds to reveal wings and a fully formed adult.
Holomeaboleous life cycles have four stages – egg, larvae, pupa then adult – forming the adult insect out of complete metamorphosis. The egg hatches into larvas, which resemble fat, short worms with tiny legs and sheds its skin during new growth. Once the larvae are large enough, they wrap themselves in a hardened shell or cocoon/chrysalis. During this pupa stage the insect is completely contained and does not eat any food. The pupa moves slightly as it grows and once it forms a new shape it breaks out of the shell as a fully formed adult insect.
The most common types of hemimetabolous insects are cicadas, cockroaches, grasshoppers or locusts and the most common types of holomeabolous insects are butterflies, true flies, or beetles.
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