They all share in the responsibility somehow. As the caterpillars grow, the students keep journals about the caterpillars, and measure and weigh them frequently. There the students can watch the caterpillar change daily and move inside of the pupa. When the butterfly emerges from the pupa, it must hang upside down and let its wings dry. From there, the students must teach their butterflies how to eat in captivity.
Butterflies eat nectar and water for nourishment.
In the classroom, juice boxes and sponges have to replicate flowers. Though butterflies taste with their feet, they do not recognize the sponges as food. So, students must pull down the butterflies straw-like tongue, called its proboscis, and teach it how to eat from the sponge. The proboscis is curled up when not in use. Once the caterpillars have matured into butterflies, the students must then tag them and set them free.