Its new exoskeleton is soft.
Molting is beneficial because the arthropod has less protection from danger than it does with its new skeleton has hardened.
Immediately after moulting the arthropod's new shell is soft and they are more vulnerable to predators. Many of them hide until their new skin expands and hardens. Some consume their old shed exoskeleton (exuviae) to recover nutrients or minerals.
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!
Because of the composition of the exoskeleton. It must of necessity be tough to serve its function. Since it is inflexible, the organism has to periodically shed it (moult) in order to grow; a process called ecdysis.
The exoskelton of an arthropod is hard, and thus cannot accomodate growth. So an arthropod must periodically replace it.
Leaves the arachnid vulnerable
Molting
Molting
Molting
The main reason is how weak and vulnerable they are just after molting. The new exoskeleton is still soft to allow growth of the animal. The other is the reason they hide DURING molting - it renders them immobile, some species have to lie on their back for hours on end and can't defend themselves.
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.