Migration strategies

[Ron Gatrelle]

Ken - I am glad you persisted in geting this throuogh the data schredder.
I shall flag this one. I usualy delete almost all my sent and received
e-drops within two weeks (most immediately after reading). Occasionally
something is worth keeping (rearely of my own making).
Ron in 72 happy South Carolina degrees.
 
----- Original Message -----
From: "Kenelm Philip" <fnkwp at aurora.alaska.edu>
To: <leps-l at lists.yale.edu>
Sent: Tuesday, January 16, 2001 4:57 AM
Subject: Re: Migration strategies
 
 
>
> (I wish I knew what was truncating this posting. Try #4)
>
> > can migration occur in one direction only?
>
> Here's an example (no doubt only one among many) of what has been said on
> this topic in the past.
>
> From 'Migration & Dispersal of Insects by Flight', C. G. Johnson,
> Methuen, 1969. In the Contents, we have:
>
> "3. Classes of Migration
> Introduction
> Class I - Emigration, without return, usually by relatively short-
> lived adults
> Class II - Emigration and return by the same, relatively short-
> lived individuals within a season
> Class III - Emigration to hibernation or aestivation sites and
> return by the same individuals after imaginal diapause"
>
> The author then points out that these classes grade into each other, and
> breaks Class I into 5 subclasses, and Class III into 3 subclasses (the
> last of which includes the North American Monarch migrations).
>
> He also defines 'migration' as synonymous with 'adaptive dispersal',
> thus short-circuiting the discussion about dispersal as compared to
> migration.
>
> And this author does seem to have applied some 'taxonomy' to the
> subject.
>
> In case anyone interprets the above, as some may have for my prev-
> ious posting re extinction, as an attempt to claim that this is the only
> correct way to look at these terms--nothing could be farther from my
> intention. All I want to do is point out that one or more knowledgeable
> people in the field have used these terms thus in the past. How other
> people may have used them, or how they _should_ be used in the future, is
> another matter.
>
> I would, however, guess that the book above (as with the Dictionary
> I referred to for 'extinction') could be considered a representative
> reference in its field. I will agree with Ron Gatrelle that you can
probably
> extract a different definition of such terms from almost every book on
> the subject one picks up. But one has to start _somewhere_...
>
> Ken Philip
> fnkwp at uaf.edu
>
>
>
>
>
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