This is how they grow.
The old exoskeleton splits, then the body expands rapidly before the new exoskeleton hardens.
The exoskelton of an arthropod is hard, and thus cannot accomodate growth. So an arthropod must periodically replace it.
exoskeleton, chitin, molting
the outter skin. as the arthropod grows, the outter skin doesn't grow with it. than it gets rid of it by molting!
Molting is beneficial because the arthropod has less protection from danger than it does with its new skeleton has hardened.
Arthropods molt (moult) in a process called ecdysis. It is necessary for growth because of the inflexibility of the exoskeleton. The old shell remnants are called exuviae. Note that the term 'anthropod' should not be confused with 'arthropod'; anthropods are humans or humanoids and do not moult in the canonic sense.
Molting
Molting
Ecdysis is when an arthropod molts its exoskeleton. Molting is necessary. The arthropod exoskeleton is inflexible, so, for it to grow larger, arthropods must molt.
Molting
Its new exoskeleton is soft.
an arthropod sheds it old exoskeleton when it has grown to a point where it needs a larger exoskeleton. This process is called ecdysis.
The act of moulting (molting) the Arthropod exoskeleton is called ecdysis.