🚀 go-pugleaf

In article <anne.643573934@trixie> anne@trixie.caltech.edu (Anneliese Lilje) writes:
>isaak@imagen.UUCP (Mark Isaak) writes:
>>in article <1990May21.202934.16658@vlsi-mentor.jpl.nasa.gov>, dave@vlsi-mentor.jpl.nasa.gov (Dave Hayes) says:

>>[regarding malathion spraying]

>>infestations.  Brian Yoder already mentioned releasing sterile flies.
>>The problems with this are (1) breeding that many flies is very
>>expensive, and (2) the wild med flies fairly quickly evolve to ignore
>>the very homogeneous sterile population, so this program doesn't work
>>over long time or in large populations.

>How do sterile med flies quickly "evolve" to ignore the very homogeneous
>sterile population?  

The comment (not by me) was that the WILD flies would evolve a distaste for
mating with the sterile flies.  Such a thing does not sound unreasonable,
but this is the first time I have heard of it.  Is this just theorizing
or has this effect been experimentally demonstrated?  Why not just
sterilize a non-homogeneous group of flies to solve the problem?

>Are the sterile med flies bred as clones?  

No, I would assume that they are bred in large numbers from a small number 
of ancestors.  After a few generations of this, one would expect to
get a more homogeneous mix than that of wild flies.

>How
>would a fertile  med fly recognize a sterile med fly?  

Because the med flies have body traits that are easily identifiable
(eye color, body shape, body markings, etc.  somewhat like "races"
in humans).  If it turns out that most of the sterile flies have
long bodies and red eyes than the wild flies will over time evolve
a distaste for mating with other flies with yellow bodies and red eyes
(I would assume there are other traits that are obvious to med flies
but not to us).

>I am just
>curious about evolution in general and I'm not quite understanding
>what this means.  Will any animal "evolve" to recognize sterile 
>subpopulations within their population?  

They will if they can recognize some trait that indicates sterility.
If there's an inherited trait for "being attracted to mate with flies
with red eyes" and most of the red-eyed flies are sterile, then the 
portion of the population with that "being attracted to mate with flies 
with red eyes" trait will become less and less common while the "being
repelled by mates with red eyes" trait will become more common.  By this
mechanism eventually the wild flies would never even try to mate with
red-eyed flies anymore and the sterile fly program would fail.

I don't know if that mechanis would really work in this case (given the
small populations of wild flies and other factors), but it's not
something that would surprise me terribly.

Brian Yoder
-- 
-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-
| Brian Yoder           | "Somehow I don't feel like killing anymore."        |
| byoder@smcnet.smc.edu |                          -- Crusty the Clown        |
-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-