Re: Mosquito, bed net/window screen, and evolution

On Tue, 17 Jul 2007 14:59:56 -0400 (EDT), dlion <not@xxxxxxxxxxxx>
wrote:


Mosquito, bed net/window screen, and evolution


A well known measure against mosquito is using bed nets and window screens.
Mosquitos' body is bigger than the hole on bed nets and window screens, so
they can't come in and bite.

But, nothing is perfect, including bed nets and windows screens. They often
have defect, a larger than normal hole, which let some mosquitos in.

I think such defect can be an effective selection pressure, which let more
smaller-body-size mosquito in, and drink blood, and breed. My hypothesis
is, in area where bed nets and window screens are widely used, the percentage
of smaller-body-size mosquito is higher than average level.

Is this hypothesis already proved true by scientist? I am eager to know.

Thank you.


It sounds like an interesting hypothesis, but there are many details
that could prevent this selection from happening. It could be that
there are quite a lot of alternative blood sources in areas where bed
nets and screens are used; whether people living in unprotected areas
or other animals that mosquitoes can use as sources of blood. It is
also very likely that defects in either nets or screens are not just
the right size to allow smaller mosquito's but prevent larger ones
from entering. There are either seams or edges that are not sealed or
rips that will allow all mosquito's, large and small, to enter. I
don't know whether there is any information about this question, but I
would doubt very much that such an effect would be seen.




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