What makes mexican jumping beans jump?
The jumping bean is not a bean, nor is it a seed. It is actually a small, thin-shelled section of a seed capsule containing the larva of a small gray moth called the jumping bean moth (Laspeyresia saltitans). After consuming the seed within the capsule section, the robust, yellowish-white larva has the peculiar habit of throwing itself forcibly from one wall to the other, thereby causing the jumping movements of the capsule. Mexican jumping bean capsules typically separate into three parts or sections, some of which contain a moth larva. It is these separate sections (technically called carpels) that are sold as "jumping beans."