Mexican jumping beans
Created | Updated Jan 1, 2009
Open your hand...
Mexican jumping beans are the seeds of a central American shrub of the genus Sebastiania. The beans themselves are slightly smaller than a jelly bean... it is important to note here that similarities extend only to size and shape but sadly not flavour or acceleration. The Mexican beans are of a red/brown colouration and their second most notable feature is that they have become popularised globally by a marked tendency to wobble infinitesimally when located in the hands of a credulous child.
Stupefaction
The property of twitching is unusual in seeds and is often used by unscrupulous adults as a means to create shock and awe in biology lessons. The terrifyingly high-pitched shrieks directed at the beans are often caused by a hastily formed belief that the beans are able to move under their own power. This common assumption is incorrect.
"Geronimo!"
The bean's celebrated "jumping" is the by-product of the larvae of a species of short lived moth called the Cydia deshaisiania1. This moth lays an egg at the centre of the jumping bean. This egg hatches into a larva that eats the middle of the bean resulting in a hollow that the Cydia Deshaisiania larva lives in as it grows. The beans that contain these larvae are the much-lauded mobile variety. This mobility is caused because the larvae are highly sensitive to changes of temperature and suffer violent paroxysms if warmed unexpectedly. Poor mites. The seizures of the sweltering grubs pull upon the strands of silk they use to attach themselves to the bean and it is this process that is the source of the bean's movement.
Ay, caramba!
The phenomena of the Mexican jumping bean are not unique to the seeds of the Sebastiania shrub, the Cydia deshainiasia or even Mexico itself. Leaping Legumes can be found on other continents.
African jumping beans:
- Spirostachys africana [Tree]
- Emporia melanobasis [Moth]
- Various Tamarisk [Tree/Shrub]
- Nanodes tamarisci [Moth]
- Oak tree [Tree]
- Neuroterus Saltatorius [Gall Wasp]2
The Arts
I want one!
Don't we all.
1Invent your own pronunciation2In this case it is during the pupal state when the pouncing become pronounced.
