Ephemeroptera (one-day flies) live months as children and hours as adults. The only purpose of the adult is to make more larvae. It cannot walk or swim. It cannot eat. All it can do is fly and reproduce. And for the 24 hours or less that they live as adults, doing nothing but fornicate, they spend the better part of a calendar year growing in freshwater ponds, lakes and streams. Over 99% of their life is childhood. And it's not because they have to learn a lot to function in adulthood.

Insects which metamorph have banished pedophilia entirely; and ephemeroptera are a case. But ephemeroptera have also, de facto, forfeited adulthood and devoted living to childhood.