The bean moth (Carpocapa saltitans) lays its eggs in the flower or in the seed pod of the spurge, a bush known as Euphorbia sebastiana. The egg hatches inside the seed pod, producing a larva or caterpillar. The jumping of the bean is caused by the active shifting of weight inside the shell as the caterpillar moves. The jumps of the bean are stimulated by sunshine or by heat from the palm of the hand.