I have a swallowtail butterfly that has just hatched indoors in the wintertime. I can't release him now. What does he need to survive?
Karen says: The swallowtail needs a safe place to be (room or pavillion) and food. You can feed the butterfly with Gaterade, Juicy Juice or sugar water (boil water and add sugar to dissolve at 10 to 1 ratio - ex. 10T water to 1T sugar). You can crumple a white paper towel on a plate and saturate it with nectar.
This book has more detailed information on raising butterflies inside.