The Jumping Bean Moth (Cydia saltitans) is a moth from Mexico that is most widely known as its larva, where it inhabits the carpels of seeds from several related shrubby trees, mainly Sebastiania pavoniana or Sapium biloculare (syn. Pleradenophora bilocularis). These seeds are commonly known as Mexican jumping beans.
The moth lays the egg on the young pod. The hatched larva gnaws into the seed, which closes the minute hole during its growth. The larva attaches itself to the bean with many silken threads by hooks on its anal and four hind abdominal prolegs. They are called jumping beans because the caterpillar can twitch itself inside the bean, causing it to move. When the caterpillar gets too hot, it moves the bean to another location where it is cool.
The larva may live for months inside the bean with varying periods of dormancy. It eats away the inside of the bean, making a hollow for itself. If the seed is cut, the larva will repair the hole with silk.
If the larva has adequate conditions such as moisture, it will live long enough to go into a pupal stage. In preparation to this, it eats a circular hole through the shell in February and closes it again with a silken plug. This is to enable the jawless adult moth to escape from the seed. After completion of the exit hole it spins a cocoon within the seed, with a passageway leading to the door. During the following pupal stage the larva will not move any more. Normally in the spring, the moth will force its way out of the bean through a round "trap door", leaving behind the pupal casing.
The small, jawless silver and gray-colored moth will live for only a few days.