on wing patterns

[Chris J. Durden]

Ron,

At 11:45 PM 2/3/2001 -0500, you wrote:


>The term eco-type is a term that every taxonomist becomes aware of early
>on. Wing patterns are often the result of genetic manifestation through
>environmental stimulation. In other words, genes don't always have free
>will. I call this: variation due to non-genetic will. The most common way
>we see this is the long employed "trick" of breeders to subject about ready
>to emerge butterfly pupae to sudden cold. All kinds of aberrations are
>produced this way because it alters (customizes) the genetic mapping.
>
>Ecotypes are not subspecies. If "subspecies" (A) from the California
>desert, when reared in the environment and on the host of a sister
>"subspecies" (B) from the San Francisco Bay area, produces adults whose
>phenotype is basically identical to subspecies (B) then (A) is not a
>subspecies. It is an ecotype - no matter how massive the range and
>consistent the pattern of the desert population is. The same holds true for
>altitudinal "forms".

I agree that there are forms that are influenced by masking regulator genes 
to produce the forms you mention. These are not however the same as what I 
learned as ecotypes. Ecotypes are the varieties that occur in balanced 
polymorphism with the "typical" genotype and can be demonstrated to be 
genetically determined. They coexist with the "typical"  genotype because 
of some bi- or polymodality of the niche. There is not enough separation of 
the modalities of selection to disconnect the genetic exchange that keeps 
them conspecific, yet the selective peaks are strong enough to keep pulling 
them apart. If they are pulled apart we have (horror of horrors!) sympatric 
speciation. This has not been convincingly demonstrated to have happened 
but I can think of a number of instances where it may have happened or be 
about to happen.
    Now where subspecies overlap it is often possible to assign syntopic 
individuals to one subspecies or the other. These are ecotypes at this 
locality. Because of slight differences of ecology we can think of all 
subspecies as ecotypes.
    I have not yet seen a convincing example of a multi-character cline 
between subspecies. What I see in the instances I have looked at are 
multi-character steps at the meeting of subspecies and these coincide with 
different elements of habitat.
...............Chris Durden


 
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