Moulting is the shedding of the hard exoskeleton periodically because it does not stretch as the insect grows bigger. All insects moult during the early stages of their life.
To moult, insects swallow a lot of air or water or use blood pressure to expand their body. The exoskeleton splits and the insect emerges.
A soft new exoskeleton is exposed when the insect gets rid of its old one. The new exoskeleton is bigger in size and allows the insect to grow.
The new exoskeleton hardens and becomes darker in colour.
Insects normally moult five to ten times in a lifetime, depending on their species.
A silverfish can moult up to 60 times in a lifetime.
The larval stage between moults is known as an instar.
Moulting takes a long time and the insect is vulnerable to predatory attacks during this period. Most insects moult in secluded areas.