Mexican jumping bean

Mexican jumping beans (also known as frijoles saltarines in Spanish) are seed pods that have been inhabited by the larva of a small moth (Cydia saltitans) and are native to Mexico. The "bean" is usually tan to brown in color. It "jumps" when mildly heated. They are from the shrub Sebastiania pavoniana, often also referred to as "jumping bean". However, they are not related to actual beans (legume plants), but rather to spurges. The beans are considered non-toxic but are not generally eaten.[1]

Jumping beans, each about 7 to 10 mm
Jumping beans shown with trap door, with holes about 8 mm deep. On one the door is separated. On the other the door is still on the beans, about 10 mm each. Also shown are the two jumping bean moths or Cydia saltitans as well as their pupal casings.

After the moth-laid egg on the plant hatches, the larva eats away the inside of the bean (until it becomes hollow) and attaches itself to the inside of the bean with silk-like thread. The larva may live for months inside the bean with varying periods of dormancy. If the larva has adequate conditions of moisture and temperature, it will live long enough to go into a pupal stage. In the spring, the moth forces itself out of the bean through a round "trap door", leaving behind the pupal casing. After its metamorphosis, the small, silver and gray-colored moth lives for no more than a few days.

As a novelty

When the bean is warmed (by being held in the palm of the hand, for example) the larva will move to eat, pulling on the threads and causing the characteristic hop.[2] Leaving the beans in a heated environment (such as direct sunlight) for more than a couple of hours can easily kill them.

The beans become energetic when a person holds them in the hand for a few minutes. The beans also appear to be a very slight shade of green on the side. When shaken near one's ear, a rattle is heard. When its hardened shell makes a softer rattle, this means that the larva has either died or entered the pupal stage.

Mexican jumping beans

Care and storage

Beans should be stored in a cool, dry place.

Beans require periodic rehydration, mimicking the monsoon weather of their native Mexico. To rehydrate the beans, they need to be soaked, but not submerged, for about three hours in chlorine-free water once or twice a month.

Sources

The Mexican jumping bean comes from the mountains in the states of Sonora, Sinaloa, and Chihuahua. Álamos, Sonora, calls itself the "Jumping Bean Capital of the World". They can be found in an area approximately 30 by 100 miles where the Sebastiania pavoniana host tree grows. During the spring, moths emerge from last year's beans and deposit their eggs on the flower of the host tree.

See also

References
  1. Marisa Demarco. "The King and Queen of Hopping Seeds". alibi.
  2. "How do Mexican jumping beans work?". HowStuffWorks. April 2000. Retrieved 4 November 2013.
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