I remember reading a great explanation, perhaps even here, on why certain cicadas have birth cycles that are prime years apart. It had something to do with preventing predators from correctly timing their births. Can someone provide the reason in layman’s terms? Are there other similar examples in nature?
Stephen Jay Gould wrote about this in one of his books. I believe the point is to prevent cicadas from not only being in synch with predators, but with successive generations of predators.
(Sorry – page won’t let me copy more, and I’m too lazy to type it all out)
Lots of other references, too:
http://www.baltimoresun.com/bal-te.ms.cicada10may10-story.html
It is for vaguely related reason that gears often have a prime number of teeth.