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Re: KillieTalk Digest V2 #443 -Reply
Hi,
You are abosutely right -- fruit flies (and microworms) require *live*
yeast that multiplies on the starchy substrate. Both cultures are
usually inoculated with baker's yeast, because it is convenient. If not
inoculated, some yeast cells will be carried on the critters and
inoculate the culture. But then other things (molds, bacteria, etc) have
a chance to take over and "spoil" the culture.
When you read that microworm cultures "smell badly" -- they were
probably started *without* addition of live yeast. With addition of
yeast the culture smells "fruity", quite inoffensive. Only a little
yeast has to be added, otherwise too much alcohol is produced. I add
about two grains of Fleischman's dry yeast per square inch of culture
medium. I use unbleached corn meal mush.
On the other hand, Daphnia and other small aquatic crustaceans are
filter feeders. *Any* suspended particles are "eaten" -- filtered out.
Some species reputedly can avoid indigestible particles. Thus yeast --
live or dead -- will be consumed if suspended in water, as will other
food, if *very finely* divided (micronized). There are reports of
raising Daphnia (and Artemia) on micronized rice bran. That's as dead as
dead can be!
Hope this helps,
Best,
George
cgraseck at ludl_com wrote:
>
> I'm not sure about this whole dead yeast thing. I read somewhere that ,at
> least for fruit flies, fermentation is the goal. When culturing fruit
> flies you add some live brewers yeast to the potato mash. The yeast
> ferments some of the potato and in the process makes the whole thing more
> nutritious. Is this statement incorrect? I don't typically have many
> problems with these cultures and I always use live yeast. Should I be
> using the dead stuff?
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