Well, you probably know this already, but butterflies have 4 stages. Egg, Pupa (caterpillar), Metamorphosis(chrysalis), and adult (the butterfly with wings). Many butterfly species fly south for the winter (notably Monarch Butterfly) and breed there, then return north for the summer and lay the eggs. I do not know the lifespan of butterflies, but I do know it's easy to grow them from caterpillar to butterfly if you know what kind of leaves they eat. I used to grow them with my sister when we were kids. Monarch Butterflies, milkweed as food. I do not know if it's possible to breed them in captivity.
All information came from memories and experience. What do you want this info for?