The Larva: It is interesting to note that even though we’ve seen dragonflies mostly flying around us during hot summer months, they spend most of their life underwater as a larva. They can live underwater for as long as two years, and this is considered to be the longest stage in the life cycle of a dragonfly.
While the larva (nymph) stage can last as long as two years, the adult dragonfly lives for 6 months.
That interesting yeah. IIRC, that’s the case for most insects - the adult forms only live to reproduce and typically the larva does the heavy lifting of growing and gathering nutrients and stuff