Different life stages can appear quite different
The different life stages of a given insect species can look completely different.
The Cecropia moth hatches from an egg to the caterpillar (larva) and does all its
feeding in this stage. It looks like a worm with legs and a head.
Then when the caterpillar has finished growing, it turns into a pupa (a cocoon in
the case of a moth), which is the stage that appears to be completely at rest.
However, there is a lot going on in the pupa! All of its immature structures,
outside and inside, are turning into adult structures.
When it emerges from this cocoon, it will be a moth with wings. As an adult, its
only job is to mate and produce offspring, so they feed only on nectar for energy.