Why do Monts need to make cocoons?
As you have seen, these insects go through many big changes while growing into adults. Their bodies take on new shapes at each stage!
Their legs are changing and they often lose the ability to move around for a belief time, Also, they need all their energy to help them grow and change. What do you think would happen if they are just sitting on a leaf or on a branch? Birds and other insects may come along and attack them. So, they make a cocoon around their bodies to remain safe. It is the same reason why butterflies make a chrysalis (a quiescent insect pupa, especially of a butterfly or moth.). Did you know that silk is made from these cocoons?