Grades 3–5 · Organisms
How can an insect grow inside a hard outer skeleton?
A young insect’s hard outer skeleton protects its body and gives muscles places to pull. But that covering cannot simply stretch larger forever. Growth requires a replacement outer layer, a process called molting.
In the diagramA new covering allows a larger bodyold coveringemerging: softexpanded: firmerA young insect molts; most adults do not keep molting.
A new covering develops beneath the old one. When the insect is ready, the old covering splits and the animal works its way out. The empty shell left behind is not another dead insect.
The fresh covering is initially soft. Before it hardens, the insect can expand its body, making room for further growth. During this period, the animal has less protection and can be especially vulnerable.
The new layer then becomes firmer. Young insects may repeat this process several times before adulthood. Molting changes the protective covering; in some life cycles, a molt also reveals a very different body form, such as an adult cicada.
About this explanation
Starting knowledge: Know that insects have body coverings and that young animals increase in size.
Sources
- Smithsonian National Museum of Natural History — How Do Skeletons Affect Animal Lifestyles?