subspeciation & ecotypes

[Chris J. Durden]

At 04:34 AM 2/4/2001 -0500, you wrote:
>Open discussion
>
>Chris Durden wrote.
>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.
>
>Ron.
>Chris, your use of the word _syntopic_  makes me think that what you are
>actually talking about are _ecotopic_  populations, which are not to be
>confused with an ecotype. An ecotopic population is a _taxa_ associated
>with a certain ecology - as a swamp or a xeric area. An ecotype is a
>_morph_ produced by the ecology. And ecotype is akin to wet/dry seasonal
>forms - where the form is simply produced by the environmental conditions.
>Usually, humidity, heat, or lack of these. If all one has to do to change
>the morph is change the humidity and thermostat, it is not a subspecies -
>period. The following have no ICZN taxonomic status: variation, form,
>aberration, ecotype

Is this the wording of the new version of the rules? I have not seen it yet.

>, and a few other terms. Why? Because they are not a
>genetically stable, long term product, of biogeographic evolution.

 From your context I think you are working with different definitions 
of  "ecotype" and "phenotype". When I learned these terms years ago the 
concepts were relatively simple. "Phenotype" referred to those (genetically 
determined) trait combinations that were expressed differently under 
different environments and corresponded to the "form" of classical 
entomologists. "Form" and "phenotype" are not included in formal 
nomenclature of interest to ICZN.
"Ecotype" referred to those (genetically determined) trait combinations 
that were expressed under most environments but were of special adaptive 
advantage under a special environment. This corresponds to the term 
"varietas" of classical entomologists. "Var." and "ecotype" are not 
included in formal nomenclature of interest to ICZN.


>It is impossible for two subspecies to exist at the same time and place.
>multiple forms, yes. Subspecies, no. What you are calling two subspecies at
>the same spot are just two forms.

Not true. Here in Central Texas we have local populations of *Kricogonia 
lyside lanice* that are present year round with larvae feeding on Guayacan. 
During fall there are large emigrations of sulphurs which include *K. 
lyside terissa* from the creosote bush deserts of central Mexico and *K. 
lyside fantasia* from the tropical evergreen forest of the Gulf Coastal 
Plain. All three subspecies may be collected at the same clump of shrubby 
boneset flowers in Travis County, Texas in October and November. We have 
one resident subspecies and two seasonally transient subspecies.

>Subspecies are definable evolutionary units - independent of their current
>environment. (Put a heard of camels in a southeastern US wetland, and
>outside of developing athletes foot, a hundred years later they will still
>be camels. Then put their offspring back into the desert and they will
>retain water for the long hall just fine.) There are many populations that
>are not assignable to any sub-species. It is like this. Think of ocean salt
>water as one subspecies and fresh river water as another water subspecies.
>Where they "meet" is actually an overlap. Of course, this is what we call
>brackish water. It is not salt water (though it is salty), and it is not
>fresh water ( though fresh water is a major percent of its composition).

I don't think this is a comparable example. It is the mixing of two fluids 
of different properties which left alone will oscillate towards equilibrium 
- either complete mixing or an euxinic situation like we find in the black 
sea. Biotic hybridization is different because there is natural selection 
acting on the offspring, influencing the oscillation towards equilibrium.

>Now, depending on the time of day and tides, it may be more salty or more
>fresh - but it is never salt water and it is never fresh water.
>
>Here is another way to look at it. Subspecies are analogous to purebreds.
>One may find a dog that "looks" like a pure whatever, but if it doesn't
>have papers be careful. For when it is bread, oops. It looked like a pure
>whatever but it was just a mongrel. A specimen from someplace which "looks"
>like some subspecies from somewhere else is not that subspecies just
>because of the way it looks. As A. B. Klots once said, to view subspecies
>this way contravenes everything that is known of systematic taxonomy.

In 99 percent of cases all we have to go on yet is looks! To identify 
something that looks like a particular subspecies as a member of that 
subspecies is a best approximation with the available evidence. If contrary 
evidence is gained later by rearing then the identification can be changed.
.............Chris Durden



>I just made a search of about 20 butterfly books and only one had the word
>ecotype in its glossary. I Found that interesting an unfortunate.
>
>Volley, and lob
>Ron
>
>PS Perhaps ecotype, as a term,  is being taught differently than the way I
>learned it from my mentors, C.F. dosPassos, Clench, Klots, etc.



 
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