First, I think the comment that I *most* agree with is the one made by Gurcharan Singh, that these conversations are endless (and will probably always be so). There are two reasons I can never seem to miss an opportunity to dive in and pontificate (Jim C., that's your cue...):
1) I usually have a slightly different perspective at the end these conversations, than I had at the beginning (always a good thing); and
2) I enjoy the intellectual challenge of trying to make the same basic points each time using a different tact, and coming from a different perspective.
Now, Pete:
When a medical entomologist states that a species X, breeds in shallow
ephemeral pools and
has a preference for human blood meals do they mean
The taxonomic hypothesis A. o. has these properties or
the "natural" unit currently called A. o. has these properties ?
Frankly, I don't think most medical entomologists think that deeply about it. In fact, I don't think most taxonomists even think that deeply about. I suspect most biologists/scientists/laymen think of species as "things" that exist in nature, and that these "things" have certain properties that are consistent enough to allow predictions and such. And I would wager that, in the vast majority of cases, they would do so with good success. That doesn't make species "real" in my mind (or even any more "real" than other taxonomic units -- in fact I think populations are probably more demonstrably "real" than species). It just makes the notion of "species as real" a practical one (as if we didn't already know that, after centuries of people thinking in those terms).
I think they mean the second and would benefit if the statements made
about that natural unit
could stay linked to the natural unit species concept over time.
Unfortunately under the "species is the taxonomic hypothesis" system they
don't.
Does this help clarify the distinction I am trying to make?
I'm not sure -- partly because I've never quite understood what people mean by "species are hypotheses". By my reckoning, it's only an hypothesis if it's testable & falsifiable. As such, it only makes sense in the context of "species are real entities in nature, and we can test whether our circumscriptions (aka taxon concepts) match those real entities". So I've always thought of "species are hypotheses" and "species are real, natural entities" as being two sides of the same coin.
So I guess I don't understand the distinction you're drawing between the two.
Aloha, Rich