# Brewer's vs nutritional yeast for fruit flies



## alex111683 (Sep 11, 2010)

Has anyone every tried nutritional yeast instead of brewers yeast? The three stores I used to get them from stopped carrying brewers and the closest I've seen is nutritional yeast. It smells exactly the same it's just nutritional is flakey. I'm guessing they have different profiles.


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## BrainBug (Aug 25, 2010)

I use nutritional yeast in my cultures. It works just as well as the brewers yeast as far as I can tell and I can get it in the bulk bins at my grocery store. 

Some of my more "naturalistic" friends also sprinkle it on just about everything they eat.


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## alex111683 (Sep 11, 2010)

Yeah. Living in Humboldt county many people use nutritional yeast. I've even seen people go into subway and bust out the yeast and ask if the worker could add it to their sub as they're making it. I think that's why stores up here stopped carrying brewer's yeast; everyone buys nutritional instead. Thank you for the response.


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## moose12 (Nov 16, 2009)

I have tried many of the commercial fruitfly culture mixes as well as brewers in the recipe approach and nutritional yeast is by far the best I've tried. I swear by it!!


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## hypostatic (Apr 25, 2011)

It should work just as well. The main purpose of the yeast in the FF cultures is to outcompete other molds and encourage the fruit flies to lay eggs


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## oddlot (Jun 28, 2010)

hypostatic said:


> It should work just as well. The main purpose of the yeast in the FF cultures is to outcompete other molds and encourage the fruit flies to lay eggs


Actually the brewers/nutritional yeast is the food/protein for the larvae and is very important and has nothing to do with mold.I believe both yeasts are pretty much the same thing and can both be used effectively.Maybe you're thinking about the sprinkle of active yeast on top of the culture?


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## alex111683 (Sep 11, 2010)

I was actually asking about the actual yeast in the media. The bakers yeast at the end for me has made no difference whether I add it or not.


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## oddlot (Jun 28, 2010)

Yes,I figured you did.Both will work fine (brewers or nutritional).The bakers yeast I've always used (I think it's what hypo was thinking about)and never tried not using it,but it works for me.


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## ndame88 (Sep 24, 2010)

Correct me if I am wrong, but Brewers yeast is used as a food souce, Bakers yeast is used to prevent mold. Nutritional yeast I am assuming is used as a food source?


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## Eric Walker (Aug 22, 2009)

I used nutritional yeast from my local organic food store for years with great results. It was a flake form just like potato flake. After my local source went out of business I switched over to a fine mill brewers yeast. Never noticed a change in production but the finer brewers yeast mixes so much better I would never go back. Only issue was I had to change my ratio of yeast to potato because one cup of the fine mill was way more then one cup of the flake


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## hypostatic (Apr 25, 2011)

Yeah, I was thinking about the sprinkle of active yeast on top of the culture.

The only thing I've really seen make a big difference is adding vinegar. This REALLY boosts production.


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## alex111683 (Sep 11, 2010)

Eric Walker said:


> I used nutritional yeast from my local organic food store for years with great results. It was a flake form just like potato flake. After my local source went out of business I switched over to a fine mill brewers yeast. Never noticed a change in production but the finer brewers yeast mixes so much better I would never go back. Only issue was I had to change my ratio of yeast to potato because one cup of the fine mill was way more then one cup of the flake


I have my ratios down pretty good according to using the Brewers yeast. Maybe I'll use a coffee grinder to make a powder from the nutritional flakes.


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## oddlot (Jun 28, 2010)

hypostatic said:


> Yeah, I was thinking about the sprinkle of active yeast on top of the culture.
> 
> The only thing I've really seen make a big difference is adding vinegar. This REALLY boosts production.



The problem I had with using vinegar is that it stinks while making them and it makes the cultures smell really bad as they age,so I don't use vinegar anymore.Between the aged stink and the wife complaining about the vinegar smell when fresh,it's not worth it for me.I used to wait until she went out to make cultures,but she would know hours later anyway. I don't notice any major differences in production with or without either.


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## Pawky (Jun 10, 2009)

I've had excellent results using bakers yeast in the media and a sprinkle of brewers when I start the culture.


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## hypostatic (Apr 25, 2011)

oddlot said:


> The problem I had with using vinegar is that it stinks while making them and it makes the cultures smell really bad as they age,so I don't use vinegar anymore.Between the aged stink and the wife complaining about the vinegar smell when fresh,it's not worth it for me.I used to wait until she went out to make cultures,but she would know hours later anyway. I don't notice any major differences in production with or without either.


Hmm, yeah, it DOES give the cultures a distinct aroma.

Vinegar is like an aphrodisiac for FFs though. In fact you can make a fruit fly trap with just some cider vinegar and a drop of detergent


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## Ed (Sep 19, 2004)

hypostatic said:


> The only thing I've really seen make a big difference is adding vinegar. This REALLY boosts production.


I have to say that I'm suspicious of the claim about vinegar..... Acetic acid isn't a limiting nutrient for the flies. The addition of nutritional/brewer's yeast is to deal with the fact that one of the primary limiting nutrients affecting productivity of the cultures is protein. 

The addition of live yeast such as active yeast is two fold, the first is that it gives the yeasts a head start on the culture potentially reducing unwanted microbes and fungi from overtaking the cultures. The second is that it helps to encourage rapid egg deposition by gravid flies. Adding it to the culture isn't a necessity as the flies themselves carry yeasts and microbes from the previous cultures on thier bodies and these will seed the cultures. Over time, these microbes actually become adapted to your culture conditions and can outcompete the added live yeasts (although this still cuts down on unwanted contaminates). 

Generally people use brewer's yeast as it can be purchased much less expensively than nutritional yeast. 

Some comments 

Ed


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## aspidites73 (Oct 2, 2012)

hypostatic said:


> Hmm, yeah, it DOES give the cultures a distinct aroma.
> 
> Vinegar is like an aphrodisiac for FFs though. In fact you can make a fruit fly trap with just some cider vinegar and a drop of detergent


I think the apple cider vinegar is more an attractant. It is the odor of fermenting fruit. I suppose the smell of decomposing fruit, to a fruit fly, may be a sort of 'Spanish Fly" to them. ie. The smell of an appropriate egg deposition site elicits that behavior. The detergent merely serves the purpose of breaking water tension so they sink, not float.


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## hypostatic (Apr 25, 2011)

aspidites73 said:


> I think the apple cider vinegar is more an attractant. It is the odor of fermenting fruit. I suppose the smell of decomposing fruit, to a fruit fly, may be a sort of 'Spanish Fly" to them. ie. The smell of an appropriate egg deposition site elicits that behavior.


Yeah this is what I meant. I don't think vinegar acts as a limiting factor to reproduction (clearly, since they'll reproduce without it), but I do believe that it "puts them in the mood" and makes them more interested in breeding.

They ARE also called vinegar flies, and for good reason.


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## aspidites73 (Oct 2, 2012)

hypostatic said:


> Yeah this is what I meant. I don't think vinegar acts as a limiting factor to reproduction (clearly, since they'll reproduce without it), but I do believe that it "puts them in the mood" and makes them more interested in breeding.
> 
> They ARE also called vinegar flies, and for good reason.



Please don't feed the trolls here: http://www.dendroboard.com/forum/ge...if-poison-dart-frogs-were-instead-called.html

They are called Drosophila !


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## Ed (Sep 19, 2004)

aspidites73 said:


> They are called Drosophila !


Cough, cough, Sophophora...... cough

Some comments 

Ed


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## Ed (Sep 19, 2004)

hypostatic said:


> Yeah this is what I meant. I don't think vinegar acts as a limiting factor to reproduction (clearly, since they'll reproduce without it), but I do believe that it "puts them in the mood" and makes them more interested in breeding.
> 
> They ARE also called vinegar flies, and for good reason.


And this wouldn't be due say to the fact that acetic acid is a byproduct of aerobic metabolism of yeast or the fact that apple cider vinegar is typically produced via yeast metabolism and the flies could be keying in on the yeast itself even though it's no longer alive (in the case of pasteurized vinegars).... 

some comments 

Ed


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## aspidites73 (Oct 2, 2012)

Ed said:


> Cough, cough, Sophophora...... cough
> 
> Some comments
> 
> Ed



They are still of the genus Drosophila. Isn't Sophophora classified as a sub-generic level?


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## hypostatic (Apr 25, 2011)

Ed said:


> And this wouldn't be due say to the fact that acetic acid is a byproduct of aerobic metabolism of yeast or the fact that apple cider vinegar is typically produced via yeast metabolism and the flies could be keying in on the yeast itself even though it's no longer alive (in the case of pasteurized vinegars)....
> 
> some comments
> 
> Ed


WELLL, if they're attracted to vinegar in the absence of yeast, it's not the yeast that they're attracted to.

They aren't thinking about how the fermented food will be easier to digest.

When I smell blueberry pie, I start to feel hungry. I believe when fruit flies smell vinegar, they start to get horny.



aspidites73 said:


> Please don't feed the trolls here: http://www.dendroboard.com/forum/ge...if-poison-dart-frogs-were-instead-called.html
> 
> They are called Drosophila !


Hey. If scientists call them that in published papers, I feel I can call them that as well. 
http://scholar.google.com/scholar?hl=en&q=vinegar+flies&btnG=&as_sdt=1,31


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## aspidites73 (Oct 2, 2012)

As long as you, like the scientific papers you cite, include the proper binomial immediately following the common name. Yes you can! I'll let ED tend to your comments on his verbage. 



hypostatic said:


> WELLL, if they're attracted to vinegar in the absence of yeast, it's not the yeast that they're attracted to.
> 
> They aren't thinking about how the fermented food will be easier to digest.
> 
> ...


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## oddlot (Jun 28, 2010)

hypostatic said:


> WELLL, if they're attracted to vinegar in the absence of yeast, it's not the yeast that they're attracted to.
> 
> They aren't thinking about how the fermented food will be easier to digest.
> 
> When I smell blueberry pie, I start to feel hungry. I believe when fruit flies smell vinegar, they start to get horny.


Haha,that's not how it works,that's not how any of this works 

Think about it.As mentioned earlier cider vinegar is fermenting fruit.If you leave an apple on a counter until it rots (and ferments) it will be loaded with wild ffs and over time larvae. It makes them hungry not horny.They EAT fruit. Being they have such a short life cycle they are programmed to eat,crap and breed, that's it,so for them to get a bite and breed at the same spot is a bonus and completes their cycle.

Besides Like Ed said, the yeast is not alive anymore,but it's still yeast so it's not absent like you're saying and if it were to make them "horny" it probably has to do with the yeast content making it a suitable breeding site. 

If your assumption was correct then my wife would be in trouble everytime I ate a steak.  I believe your thoughts are pure speculation but I'd be interested in reading a source (other than Wikipedia) that proves your statement if you have one.


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## hypostatic (Apr 25, 2011)

WHEW. It took me a while to find some literature. Putting "drosophila" "vinegar" "horny" into google scholar doesn't seem to yield relevant results for some reason.....

Link to the abstract:
Oviposition rhythm in Drosophila melanogaster is influenced by acetic acid

Summary of the abstract -- fruit flies lay eggs twice as often on food that has vinegar vs plain food. On plain food, a pulse of acetic acid fumes could induce a second oviposition event.

Fruit flies don't care about yeast. They don't know yeast even exists. They live in a fuzzy grayscale world of chemical signals. Yeast can't shout out from across a room to invite a fly over. Vinegar however, is volatile and aromatic -- it can waft and diffuse across a room, showing the fly where the source is via an increasing gradient. This is why you can make a fruit fly trap using nothing but vinegar. The fly doesn't contemplate whether or not it's a suitable breeding site. The vinegar simply elicits a response and the fly follows through.



oddlot said:


> If your assumption was correct then my wife would be in trouble everytime I ate a steak.


I believe the old saying is "the way to a man's heart is through his stomach" (I think for women it might have to do with shoes). People and fruit flies might not be too different after all


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## Ed (Sep 19, 2004)

hypostatic said:


> . Summary of the abstract -- fruit flies lay eggs twice as often on food that has vinegar vs plain food. On plain food, a pulse of acetic acid fumes could induce a second oviposition event.


The problem with this summary is that you ignore the claim as to production of the culture. The flies may lay eggs more frequently but they don't lay more eggs. See the abstract as it clearly states they lay less eggs during the normal evening deposition time as a consequence. This does not support your claim of increased production because vinegar is added to the media. It may actually contradict it since the flies do not lay more eggs as a result. 



hypostatic said:


> Fruit flies don't care about yeast. They don't know yeast even exists. They live in a fuzzy grayscale world of chemical signals. Yeast can't shout out from across a room to invite a fly over. Vinegar however, is volatile and aromatic -- it can waft and diffuse across a room, showing the fly where the source is via an increasing gradient. This is why you can make a fruit fly trap using nothing but vinegar. The fly doesn't contemplate whether or not it's a suitable breeding site. The vinegar simply elicits a response and the fly follows through.


Did you even bother to look at the literature before making such a definitive claim? I suggest you read Yeast, not fruit volatiles mediate Drosophila melanogaster attraction, oviposition and development - Becher - 2012 - Functional Ecology - Wiley Online Library

Yeast, not fruit volatiles mediate Drosophila melanogaster attraction, oviposition and development; Paul G. Becher1,2,*, Gerhard Flick3, Elżbieta Rozpędowska1,2, Alexandra Schmidt1,3, Arne Hagman2, Sébastien Lebreton1, Mattias C. Larsson1, Bill S. Hansson4, Jure Piškur2, Peter Witzgall1 andMarie Bengtsson1; Functional Ecology Volume 26, Issue 4, pages 822–828, August 2012

Melanogaster actually demonstrates an olfactory avoidance to 5% acetic acid which is ignored when ovipositing because the choice of ovipositioning sites is determined through oral detection. See http://www.pnas.org/content/106/27/11352.full 
Biological Sciences - Neuroscience:
Ryan M. Joseph, Anita V. Devineni, Ian F. G. King, and Ulrike Heberlein
Oviposition preference for and positional avoidance of acetic acid provide a model for competing behavioral drives in Drosophila
PNAS 2009 106 (27) 11352-11357

So we can debunk the claim that the flies do not detect the yeast.. we can also see that the proof that vinegar increases production of a culture is still lacking as an increase in ovipositioning does not necessarily equate to more eggs produced. 

Some comments 

Ed


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## Ed (Sep 19, 2004)

aspidites73 said:


> They are still of the genus Drosophila. Isn't Sophophora classified as a sub-generic level?


At this time they still are but the sub-generic level is considered paraphyletic so I would expect some more changes in the future.

Some comments 

Ed


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## Ed (Sep 19, 2004)

hypostatic said:


> WELLL, if they're attracted to vinegar in the absence of yeast, it's not the yeast that they're attracted to.


And where is the demonstration that they were attracted to vinegar in the absence of yeast? 
I think the literature pretty much puts to bed the claim that the flies are not attracted to the yeast. 



hypostatic said:


> They aren't thinking about how the fermented food will be easier to digest.


I'm not sure how you got to this claim. Foods that are being broken down by yeasts and other microbes are going make accessing the nutrients easier as consumption of the yeast/microbes is going to give direct access to those nutrients in a more concentrated form.... as well as breaking down the plant tissues. 



hypostatic said:


> When I smell blueberry pie, I start to feel hungry. I believe when fruit flies smell vinegar, they start to get horny.


Ovipositioning and mating are two seperate behaviors, to this point you've claimed that exposure to acetic acid and not yeast drove increased egg deposition (aka production) and this has not been demonstrated to date. If you going to expand the claim, you need to expand the proof. 
The literature indicates that acetic acid can also act as an avoidance stimulus..... 



hypostatic said:


> Hey. If scientists call them that in published papers, I feel I can call them that as well.
> http://scholar.google.com/scholar?hl=en&q=vinegar+flies&btnG=&as_sdt=1,31


Sadly this justification doesn't mean anything other than an attempt to ignore proper nomenclature. Under this argument, the Australian herpetologist Raymond Hoser's reclassification of rattlesnakes would be just as valid as the accepted nomenclature. See for example http://www.smuggled.com/AJHI6.pdf and Taxonomic vandalism and the Raymond Hoser problem | Tetrapod Zoology, Scientific American Blog Network 

The fact that the correct nomenclature in an article doesn't mean that the correct nomenclature isn't what should be used. 

Some comments 

Ed


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## aspidites73 (Oct 2, 2012)

I do see your reasoning but, I remain unconvinced. First, it is very difficult, if not impossible to extract known valid data when only an abstract is used from a single experiment. It is merely the author(s) summary of their interpretation of the results. All we know is that the experimenter(s) came to the offered conclusion. 

That being said, I believe the main limiting factor to us being on the same page is the rather non-scientific and vague term "horny" being tied to the very specific term "oviposition". My understanding of the term "horny" is: it is time to have sex. Oviposition is not sex. In fact, in our example. the sex is already over when oviposition takes place. It would be more accurate to say that odor  stimulates oviposition. 

EDIT: I was typing this as Ed replied above. 



hypostatic said:


> WHEW. It took me a while to find some literature. Putting "drosophila" "vinegar" "horny" into google scholar doesn't seem to yield relevant results for some reason.....
> 
> Link to the abstract:
> Oviposition rhythm in Drosophila melanogaster is influenced by acetic acid
> ...


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## hypostatic (Apr 25, 2011)

So while we don't know the exact details of the publication, I feel pretty confident about the peer-review process, and that all the reviewing scientists felt that the data was compelling enough for publication. There's actually a few different experiments mentioned in the abstract, but it doesn't mention how many times the experiment was repeated.

That being said, only having access to an abstract does have its caveats since we don't know the particulars. The abstract says that vinegar-food would induce the flies to lay eggs twice per day, versus once for the control. As you guys have mentioned, the abstract doesn't quite mention the exact NUMBER of eggs laid during each event. I'm operating under the assumption that each oviposition event results in roughly the same amount of eggs.

Here's another article that you guys might have access to:
Oviposition preference for and positional avoidance of acetic acid provide a model for competing behavioral drives in Drosophila

I'll draw your attention to this figure:









It seems what you're saying is correct Ed. Flies DO seem to have some aversion to vinegar. Males seem to want to have nothing to do with it. Females also don't like hanging around it. Unless they're laying their eggs, that is.

If you look at (D), you'll see that when given a choice between media with vinegar and without vinegar, the VAST majority of eggs were laid on the vinegar media. The authors of this paper additionally cite 2 other papers which found similar results -- "Similar to previous observations, mated females laid approximately 91% of their eggs on food containing 5% AA (Fig. 1 B and D; +AA) as compared to regular food"

I don't know why this is being contested so much. You can make your own fruit fly trap that has literally nothing besides vinegar to attract fruit flies. They're certainly not being attracted to the traps by yeast, since there is none in the media.


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## aspidites73 (Oct 2, 2012)

I thought was was being discussed was your claim that vinegar causes increased production in and of itself.


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## hypostatic (Apr 25, 2011)

OHHHH right. 

okay. so the first paper abstract claimed that flies on media with vinegar would lay eggs twice per day, versus once per day on plain media. I assumed this translated to twice as many eggs. I certainly feel that this is in line with what I've seen in my own cultures, and it's why I've never gone back to not using vinegar once I've started.

I'm actually having a hard time finding hard numbers for how many eggs should be laid during one event. I've found some more articles but they're not online. I've placed an interlibrary loan request on a few articles and I'll get back to you with more details when/if I get the articles.

I actually just recently used to work next to a fly lab. If I was still there I coulda just asked someone....


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## Ed (Sep 19, 2004)

hypostatic said:


> That being said, only having access to an abstract does have its caveats since we don't know the particulars. The abstract says that vinegar-food would induce the flies to lay eggs twice per day, versus once for the control. As you guys have mentioned, the abstract doesn't quite mention the exact NUMBER of eggs laid during each event. I'm operating under the assumption that each oviposition event results in roughly the same amount of eggs.


Really? Then your reference doesn't support your claim of increased production at all. All it establishes is that instead of one primary egg oviposition event at dusk there are two and the abstract clearly states that fewer eggs are deposited during the dusk event. A critical reading of the abstract also doesn't indicate that a constant acetic acid exposure results in more than one oviposition event or that it increases production as you claimed.. see quote below. 



hypostatic said:


> The only thing I've really seen make a big difference is adding vinegar. This REALLY boosts production.


The emphasis is all yours... as I stated above in post #16 that I was really suspicious about the claim that vinegar increased production. 



hypostatic said:


> Here's another article that you guys might have access to:
> Oviposition preference for and positional avoidance of acetic acid provide a model for competing behavioral drives in Drosophila


I'm guessing you either didn't read my post above (post #27) where I oddly enough referenced that exact paper. 



hypostatic said:


> If you look at (D), you'll see that when given a choice between media with vinegar and without vinegar, the VAST majority of eggs were laid on the vinegar media. The authors of this paper additionally cite 2 other papers which found similar results -- "Similar to previous observations, mated females laid approximately 91% of their eggs on food containing 5% AA (Fig. 1 B and D; +AA) as compared to regular food"


As I noted in post number 27, the flies show an olfactory aversion and demonstrate that this is overridden by gustatory (oral) detection. So I'm not sure why you are suddenly rewording my points.... 



hypostatic said:


> I don't know why this is being contested so much. You can make your own fruit fly trap that has literally nothing besides vinegar to attract fruit flies. They're certainly not being attracted to the traps by yeast, since there is none in the media.


The point is being made because you have continually gone out of your way as an attempt to defend that the vinegar increases production in some mysterious way including claims that vinegar increased courtship, increased oviposition, that the flies can't detect yeast and so forth. None of that has been supported by the literature. However, it is now clear that I shouldn't have been polite and said it was suspect as opposed to calling it pure and simple BS.

As for not being able to detect yeast products in vinegar. What do you think makes vinegar? For example how do you get cider, wine, sherry, balsalmic, malt etc vinegars without yeast? Do you think all of the potential yeast olfactory cues are removed from those products? 

And this is before we consider that wild yeasts are also present and can begin to ferment substrates in a relatively short period of time. 


Some comments 

Ed


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## hypostatic (Apr 25, 2011)

I understand that yeast makes vinegar. But if I'm understanding correctly, you're saying that it's not the smell of acetic acid (and I'm also inferring any other volatile aromatic compound like ethanol) doesn't attract fruit flies. They are, however, attracted by the smell of yeast. Is this correct?


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## aspidites73 (Oct 2, 2012)

In the words of Albert Einstein: "No amount of experimentation can ever prove me right; a single experiment can prove me wrong."

and, my favorite Einstein quote should sum it up: 

"Anyone who has never made a mistake has never tried something new."

I have learned a lot in this thread. Thank you!


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## moose12 (Nov 16, 2009)

You're all such nerds...I love it!! PLEASE friend me!!


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## Judy S (Aug 29, 2010)

paraphyletic?? You all are giving me nightmares....


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## aspidites73 (Oct 2, 2012)

Judy S said:


> paraphyletic?? You all are giving me nightmares....


Phylogenetics is the study of evolutionary relationships among groups of organisms


Science Dictionary
paraphyletic (pār'ə-fī-lět'ĭk) Pronunciation Key 
Relating to a taxonomic group that includes some but not all of the descendants of a common ancestor. In the traditional taxonomy of vertebrates, where fish are a separate class from the classes of terrestrial vertebrates, the class of fish is paraphyletic, since the terrestrial vertebrates are descended from a type of fish. Compare monophyletic, polyphyletic. 

Accessed from here -> Paraphyletic | Define Paraphyletic at Dictionary.com

From para- (“near”), Ancient Greek φῦλον (phûlon, “tribe, race”), and -ic.

Accessed here -> http://en.wiktionary.org/wiki/paraphyletic


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## Ed (Sep 19, 2004)

hypostatic said:


> I understand that yeast makes vinegar. But if I'm understanding correctly, you're saying that it's not the smell of acetic acid (and I'm also inferring any other volatile aromatic compound like ethanol) doesn't attract fruit flies. They are, however, attracted by the smell of yeast. Is this correct?


Unlike your position where the yeast plays no input on the lure of the vinegar or that vinegar increases production. I'm making an alternative point. Your claim that the flies are drawn to the vinegar has a problem in the fact that none of your claims have a control where yeast is excluded from the experiment. In the feeding trials, there is no indication that the flies are sourced from sterile cultures which means active live yeasts are transferred to the experimental medias via the flies. Secondly the vast majority of vinegars are from the aerobic fermentation of fruit juices by yeast. So the issue is whether the flies are truly attracted to the vinegar itself or to the molecules of yeast still in the vinegars. This is before we consider the impact that fruit juices generally contain yeasts either active or inactive depending on whether or not it has been pasturized... 

But this is a digression. I stand by my comment early in the thread that any claims that vinegar increases productivity of a culture is at best a misunderstanding and at worst pure BS. 

Some comments 

Ed


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## aspidites73 (Oct 2, 2012)

I'm not certain the most important lesson learned here is that of olfactory capabilities, or lack there of. I think the most important ideas in this thread are, and in no particular order: Correlation does not imply causation, critical reading/thinking is an indispensable and invaluable tool and ALWAYS question. Especially when you think something is unquestionable.


EDIT: Yet again Ed beat me to a summation post!



hypostatic said:


> I understand that yeast makes vinegar. But if I'm understanding correctly, you're saying that it's not the smell of acetic acid (and I'm also inferring any other volatile aromatic compound like ethanol) doesn't attract fruit flies. They are, however, attracted by the smell of yeast. Is this correct?


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## oddlot (Jun 28, 2010)

aspidites73 said:


> EDIT: Yet again Ed beat me to a summation post!


 Haha,you have to be quicker to the draw,he gave you a couple of days on this one.


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## aspidites73 (Oct 2, 2012)

Yet, he only beat me by < 10 minutes! 



oddlot said:


> Haha,you have to be quicker to the draw,he gave you a couple of days on this one.


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## ecichlid (Dec 26, 2012)

Sooooooo, I use baker's yeast, would I likely see an increase in production if I switch to brewer's yeast? There's a beer brewing store right next to my office, so it would be no trouble to get some.

I would do anything to increase fly production. If Ed found a paper that supported the idea that hopping on one foot while making cultures improved results, I would be hoppin'.


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## oddlot (Jun 28, 2010)

ecichlid said:


> Sooooooo, I use baker's yeast, would I likely see an increase in production if I switch to brewer's yeast? There's a beer brewing store right next to my office, so it would be no trouble to get some.
> 
> I would do anything to increase fly production. If Ed found a paper that supported the idea that hopping on one foot while making cultures improved results, I would be hoppin'.


Absolutely! (if you're talking about in the media) The brewers yeast is the nutritional protein that gets the larvae going.The bakers yeast is just used as a topical and very lightly sprinkled on. Brewers yeast in the media,bakers yeast on top.


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## ecichlid (Dec 26, 2012)

Ohhhhh, I see now. I'm just too lazy to even think about making my own media. If I had as many frogs as you do Lou, then I absolutely would. Ok, good to know I'm on the right track.














I think.






I've even taken a tablespoon lukewarm water and mixed some yeast to that water before I drip it over the top of my cultures. While hopping on one foot.


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## Ed (Sep 19, 2004)

ecichlid said:


> Sooooooo, I use baker's yeast, would I likely see an increase in production if I switch to brewer's yeast? There's a beer brewing store right next to my office, so it would be no trouble to get some.


There appears to be somewhat of a misunderstanding here... The brewer's yeast that is used to increase the protein content is not alive. Its deactivated and used as a nutritional supplement for many things. You want inactive brewer's yeast not the stuff you add to ferment the mixture. 
Inactive brewer's yeast and nutritional yeast are the same for our purposes in fruit fly culturing. 

Adding too much protein can also cause problems with the cultures as the protein can decompose and render the culture conditions hostile to the flies as one of the decomposition products is ammonia. 

It can be purchased relatively inexpensively from some of the sponsors or you can search the web for it. 

I would only suggest adding it if you are making your own custom mixture 



ecichlid said:


> I would do anything to increase fly production. If Ed found a paper that supported the idea that hopping on one foot while making cultures improved results, I would be hoppin'.


Try mixing the media inside a circle of solomon while wearing clown makeup. 

Some comments 

Ed


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## Ed (Sep 19, 2004)

ecichlid said:


> I've even taken a tablespoon lukewarm water and mixed some yeast to that water before I drip it over the top of my cultures. While hopping on one foot.


This activates the baker's yeast and gets it colonizing the media more quickly. I add a couple of drops of water to the surface of the media before I sprinkle the baker's yeast onto the media. 

The flies and their larvae will eat this yeast just well and it provides nutrients however it is more likely that the nice strain of yeast from the package will be displaced by a strain more acclimated to the culture conditions and brought to the culture by the flies. 

Some comments 

Ed


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## carola1155 (Sep 10, 2007)

ecichlid said:


> Sooooooo, I use baker's yeast, would I likely see an increase in production if I switch to brewer's yeast? There's a beer brewing store right next to my office, so it would be no trouble to get some.


In addition to what Ed said... this would also be a very expensive endeavor. Active brewer's yeast is usually a few bucks ($3-5) for a little 11.5 gram sachet. It would be several times more expensive. Plus, you'd be making me depressed from knowing that there could have been alcohol made with that stuff and you chose to use it for flies.


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## ecichlid (Dec 26, 2012)

Thank you guys!


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