This way, they see the miracle of the life cycle, from a caterpillar to a beautiful butterfly flying around. Right now Passmore has two monarch butterflies, both in the chrysalis stage. You can t make anything as beautiful as that. Though they re technically the same animal, caterpillars and butterflies behave extremely differently. While monarch butterflies feed on nectar, monarch caterpillars, which are striped in black, white, and a fluorescent yellow, stay close to milkweed and feed on it.
Most caterpillars feed on plants, until they become large enough to enter the pupa phase of life.
When large enough, the monarch caterpillar latches one end onto a branch of the milkweed and then a strange thing happens, as Boyle pointed out. The caterpillar begins squirting out a green slime that covers its entire body. After about 20 minutes, it s no longer a caterpillar, but a chrysalis. Now, Passmore s third-graders have nothing to do but wait for a week or two while the pupa goes through its incredible metamorphosis. Before long, the chrysalis will turn from a green to a translucent purple, and then an orange, four-winged butterfly will emerge.