From: scerir (scerir@libero.it)
Date: Sat Jun 08 2002 - 01:19:25 MDT
Spike:
> I fear that my musings have caused me to become peta-
> ntic. I dont want to have to zetta precendent here
> by hogging the fun, nor do I wish to overstate or exa-
> gerate the importance of such near perfect odd numbers.
Overstate? Look ...
'Periodical cicadas (Magicicada spp.) are known for their strikingly
synchronized emergence, strong site tenacity, and unusually long
(17 - and 13 - yr) life cycles for insects. Several explanations have
been proposed for the origin and maintenance of synchronization.
However, no satisfactory explanations have been made for the origins
of the prime-numbered life cycles. I present an evolutionary
hypothesis of a forced developmental delay due to climate cooling
during ice ages. Under this scenario, extremely low adult densities,
caused by their extremely long juvenile stages, selected for
synchronized emergence and site tenacity because of limited mating
opportunities. The prime numbers (13 and 17) were selected for
as life cycles because these cycles were least likely to coemerge,
hybridize, and break down with other synchronized cycles.'
- J. Yoshimura, 'The evolutionary origins of periodical cicadas during
ice ages', American Naturalist, 149(1), 112-124, (1997)
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