Before that “giant” bug showed up as an unexpected guest at your first barbeque of the spring, it started off life as a tiny egg. The process of growth and development that most insects experience is known as metamorphosis. During this process, insects will change shape, form and size until they reach the adult stage. There are several different types of metamorphosis including gradual metamorphosis, incomplete metamorphosis, and complete metamorphosis.
Some insects, however, grow and develop without metamorphosis. These insects, such as silverfish, grow and develop through a series of molts. When an insect’s exoskeleton no longer stretches to accommodate its size, it must shed this exoskeleton and grown a new one, while going through an intermediate phase known as instar. Until the insect reaches adulthood, or sexual maturity, it goes through several nymph stages that have the same appearance as the adult. At adulthood, molting ceases.
The insects that experience gradual metamorphosis include cockroaches, termites, bedbugs, and earwigs. They have three distinct stages in development – egg, multiple nymph stages, and adulthood. The nymphs begin to gradually resemble the adult as they grow, but do not have wings.
During incomplete metamorphosis, which occurs for dragonflies, damselflies, and mayflies, insects experience a transition from egg to naiad to adulthood. Naiads possess a different body structure and way of life from the adults. These nymphs live in water whereas the adults live on dry land and have wings.
The last form of complete metamorphosis occurs in beetles, moths, butterflies, flies, fleas, ants, bees and wasps. They go through four stages: egg, larva, pupa, and adult. Each stage has a different appearance. The larva hatches from the egg and then goes into a resting stage known as the pupa. During this stage, the insect changes from larvae to adult and fully develops its wings, legs, and antennae before emerging.
Sources:
Georgia Pest Control Employee Registration Manual