What Causes The Mexican Jumping Bean To Move?
The movement of the Mexican jumping bean occurs when a bean moth (Carpocapa saltitans) larva (larva is the wormlike, juvenile form of an organism) shifts within the shell of a bean from the spurge bush (Euphorbia sebastiana). The adult female bean moth lays its eggs in the flower or in the seed pod of the spurge. Once an egg in the seed pod hatches, it produces a larva inside a seed, or bean. The larval movement is stimulated by sunshine or by heat from the palm of the hand.
Source: Nature Magazine, vol. 38 (1945), pp. 473-74.