Just a basic biology question. Why do insects have a larval stage prior to pupating and then turning into an adult moth, butterfly or whatever? It's probably a survival mechanism, to increase the survival rate of the species is my conclusion. Some insects undergo complete metamorphosis and others have an incomplete metamorphosis.
It is, as you say, a survival mechanism. Many insects eat far more in their larval stage then they do in their adult stage. In fact some moths and butterflies can't eat at all because their mouth parts don't develop (an evolutionary trait). In such insects, the adult stage serves no purpose other than to enable reproduction.
