Those few adults....

[Kenelm Philip]

	In a recent posting on the Miami Blue, Ron Gatrelle said:

> One has to remember that adult butterflies are only a small portion of
> any species overall population.

That's quite true if you pick the right time to make your census. Right
after oviposition the population can jump to around 250 times the total
number of adults. However, the survival of a species is critically depend-
ent on the number of _reproducing_ individuals. If there were indeed only
50 adults, the 12500 ova they produce is not the major factor in survival
of the colony. For example, consider the case of only 10 adults (and thus
2500 ova). The sex ratio for the 2500 ova will almost certainly be near
50% male/female--but there is now a distinct possibility that the next
generation of adults could be all of one sex--in which case those 2500
ova are doomed. Think of butterfly adults as a bottleneck, through which
the entire population must pass each generation...

							Ken Philip




 
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