the mystery of Vanessa unidirectional migration

[Tony Cynor]

Hi Liz:

This behavior may go back to when world climate patterns were different.  You
are probably right in that we cannot see the whole picture.

Tony

Liz Day wrote:

> I don't understand what advantage this bug gains by migating north every
> spring, if the adults don't then migrate back south in the fall, and (?)
> thus their offspring are instead killed off by winter.  Isn't this genetic
> suicide?   I understand dispersion is good, but it seems like consistent
> directional dispersion in a direction that is ultimately death would be
> selected against, eventually.   What is going on?  I must not be seeing the
> whole picture.
>
> Thanks,
>
> -------------------------------------------------------------
> Liz Day
> Indianapolis, Indiana, central USA  (40 N, ~86 W)
> USDA zone 5b.  Winters ~20F, summers ~85F.  Formerly temperate deciduous
> forest.
> daylight at kiva.net
> www.kiva.net/~daylight
> -------------------------------------------------------------
> "It is quite remarkable, when you think of it, that if you tell somebody to
> buy something and dump it on or squirt it on, he will almost certainly do
> it, after a fashion. But if you suggest that he observe something or think
> about something or learn about something, he almost certainly will
> not. Yet those gardens we admire are never the results of dumping and
> squirting: they are always the result of muddling things about in the brain
> and the eye."
> -- from _The Essential Earthman_, by the late Henry Mitchell
>
>
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