Is the eastern tiger swollowtail butterfly nocturnal?

Answer 1

Some species are nocturnal (the migrating ones, which have to fly over large bodies of water and don't have a place to rest) and even though there are night sightings of active dragonflies, that aren't migrating, these insects are normally diurnal (day-active).

Answer 2

No. Many moths are nocturnal but very few if any butterflies are nocturnal. Butterflies are cold-blooded and need the sun to help regulate their body temperature. That's why you see more butterflies on a warm, sunny day.