Subspecies

[DR. JAMES ADAMS]

Leppers,

         Ah, finally my extremist side comes out!

          I am in agreement with Ken Phillip about the lack of 
utility of the subspecific taxonomic rank.  I am definitely more 
extreme than Ken, however, so I'm sure Mark Walker may have something 
to say about my comments.

Ken wrote: 
 >But the history of applying
> names to arctic butterflies tends to look like this: person A makes a
> trip to arctic region X at some longitude, and describes a new butterfly.
> Then person B visits arctic region Y at a different longitude, finds
> a butterfly that looks a bit different from the first one, and describes
> a new subspecies. No one involved has any information as to whether the
> two 'subspecies' are possibly merely arbitrary points from a cline--which
> in fact they may be, but that fact won't emerge until a _lot_ of trips
> have been made to intermediate longitudes (not easy, or inexpensive, in
> these roadless regions).

I would suggest that this applies to a number of supposed 
"well-delineated" subspecies of western butterflies as well.  I have 
had the opportunity to look at series of Euphydryas from many 
different populations in the west -- I will grant you that different 
"subspecies" may have differences in the modal (middle-of-the-curve) 
specimens.  However, anyone who has every looked at populations of 
Euphydryas knows very well that there is typically a lot of pattern 
variation within each population, enough so that the variation of 
one "subspecies" clearly encompasses that of many others.  The 
utility of maintaining these different subspecific names under these 
circumstances escapes me.  If you want to simply use the subspecies 
names to represent populations of a species from different places, 
without regard to any sort of distinctive genetic differences, then 
go ahead.  This is *not*, however, how the category should be used, 
but I would have less problem with it if it was, as Ken sort of 
suggested.  It *would be* particularly useful if, as Ken suggested, 
different populations were given names based on their geographic 
locations.  Whether or not this had any foundation in any sort of 
genetic difference, if this is the way we defined the use of the 
subspecific category, it certainly could have a lot of utility.  (I'm 
not necessarily suggesting this is the way it should be done!)

         On the flip side, if you do discover a truly isolated 
population, with presumably its own genetic history, with basically 
no gene flow with other populations of the same "species", then I can 
see *some* utility in the subspecific rank.  However, at this point, 
it is completely arbitrary whether you should call this a subspecies 
or a completely separate species, as this population is now off to 
pursue its own evolutionary potential.  The only way you could "find 
out" if these populations are species or subspecies is if they then 
came back in contact with other populations and if there was then 
gene flow between them.  Needless to say, you have to have a lot of 
pretty specific information to convince me that some population 
should be considered a subspecies of anything!

Ken also wrote:
> 	I am talking here about old-fashioned morphological subspecies.
> When you start with DNA I suspect the number of subspecies could become
> astronomical.

I would actually argue that the number of subspecies would actually 
decrease -- it would be the number of *species* that would increase 
astronomically.  We're heading off toward another thread that was 
running a few weeks ago about defining species based on actual DNA 
differences, and we don't really need to go there again.  My point is 
still, however, that the subspecies rank is, in many cases, extremely 
overused.  As for Euphydryas, I'd just scrap all the subspecies and 
start over . . . hey, it's not going to happen, but, as Ken says, I 
can dream . . .

Ken wrote: 
> 	Now I can prepare to receive the brickbats which will presumably
> be heading my way...

Ditto.

          James

Dr. James K. Adams
Dept. of Natural Science and Math
Dalton State College
213 N. College Drive
Dalton, GA  30720
Phone: (706)272-4427; fax: (706)272-2533
U of Michigan's President James Angell's 
  Secret of Success: "Grow antennae, not horns"