Jumping beans

[monique at bio.tamu.edu]

>A friend has brought me a jumpin bean from Mexico. It moves by itself!
>I would know why moves it by itself.
>What's in the jumping bean. Is it an alien in? I can't sleep at night 
>for a month.
>My friend has told me that it moves when a change of temperature and 
>humidity, but I don't understand nothing.
>I need somebody to help me!

A "jumping bean" is the seed of a species of _Sebastiana_  or _Sapium_.  It 
moves because it has a tiny worm (the larva of  a small moth) inside.  The 
insect lays its eggs in the seed, and the larva eats the seed from the inside 
and eventually hatches.  When you hold one of the "beans" in your hand, the 
warmth stimulates the larva to wriggle around, making the bean "jump."

No aliens, and maybe now you can get a good night's sleep.

Monique Reed
Texas A&M University