[Drosophila] Hot Weather

Mark Thorson via dros%40net.bio.net (by nospam from sonic.net)
Wed Aug 8 13:30:13 EST 2012


Geoffrey RICHARDS wrote:
> 
> If you are pouring a cooked medium, the problem may come in the cooling phase when they are giving off vapor.
> It may be that making up the medium in a cooler part of the day would help.
> 
> Perhaps nothing to do with your problem but worth considering.

Thanks for the advice, but I'm not cooking my medium.
It's bananas, yeast, cream of tartar, and water.
I haven't had any mold problems, though some minor
problems with bacteria.

I've thought about aging the medium after mixing.
Right now, I mix the medium, fill the culture
vessels, and add flies.  The medium foams up
starting while I mix and continuing for several
hours.  I lose a few adults in the foam, and I
have considered aging the medium for 24 hours
to get past the foamy stage, but I'm not losing
very many adults at that point.

I'm losing a lot more adults about 4 to 5 days
later.  I'm not sure why.  I think it's due to
excess carbon dioxide accumulation, but I've also
considered the possibility they're dying of
thirst or hunger -- though there's lots of moist
yeast available at that point, so I don't see
how that would be a problem.  I always sniff
my cultures, and I've noticed some cultures have
a sort of "bite" in the aroma at that point
which I think is carbon dioxide.



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