09-30-2009, 11:07 AM
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discere et docere
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Join Date: Apr 2009
Location: Louisville Kentucky
Posts: 627
Classified Rating: 0% (0) |
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I'm always messing around with fruit fly media recipes, for me I think the 50/50 water vinegar mixture is a bit vinegar heavy.
I use between 6.25% (15:1 water vinegar ratio) and 12.5% (7:1 water vinegar ratio).
I use brown sugar and not white (brown sugar has some nutrient value). Brown sugar does not lend itself well to premixing dry ingredients so it is measured and added to the water on a per culture basis.
So for a 1c culture (in a 32oz Deli cup);
Add and mix well:
1/2c 15:1 to 7:1 distilled water + vinegar mixture
1tbps brown sugar
Combine then add to above (stir with a chopstick or similar item):
1tbsp brewer’s yeast
1/3c instant mashed potatoes
Proof the active yeast, in a second container mix together:
1c plain warm water (90° to 100°F)
1tbsp brown sugar
1tbsp instant yeast
If foam develops in the above mixture:
Add 2tsp to the culture as evenly as possible.
Top up the culture with your favorite surface area improver (I use excelsior).
Add 50ish flies of your desired type.
Lid the container.
The surface area improver, temperature, humidity, and airflow in the area you store your cultures will be a factor in exactly how much water vinegar and what ratio you will find best results with.
No mould = reduce vinegar
Mould = increase vinegar
Culture dry (never produces) = increase water vinegar mix
Culture wet (culture produces) = decrease water vinegar mix
Culture media raises excessively (forms air pockets) = reduce proofed yeast
It helps to write on the side of your initial batches of flies exactly what and how much of each ingredient was used in the culture. Also add the date you started the culture, the date larvae are noticed, the date pupae are formed, and lastly the date new flies are produced. This way you can play around with ingredient quantities in a methodical manner.
For those who cannot stand the smell of fly cultures you can replace some of the brewer’s yeast with ground cinnamon (start with an 11:1 brewer’s yeast to ground cinnamon ratio and work up from there).
If brewer’s yeast is not available to you or you simply like to mess around with things use powdered milk or powdered infant formula in its place. Any combination of the three should work; nutritionally speaking infant formula and brewer’s yeast are the better ingredients.
For the truly adventurous, try any of the brewing yeasts designed for beer, wine, etc. these are far more expensive than baker’s yeast but yield some interesting smelling cultures and I suspect a slightly different nutrient content because you are using a different strain of yeast.
If you live in a high mould area the vinegar and yeast in your culture may not be enough to retard mould development. If this is the case there are a number of mould inhibitors out there that will stop mould in its tracks. I use tegosept, others use methyl paraben, you want to use the smallest quantity that gets the job done, because these are expensive ingredients with no nutritional value. Adding too much mould inhibitor will stop a culture from producing and too little will do nothing to prevent mould.
Take this into consideration when buying ingredients, people just don't cook and bake like they used to. Fresh ingredients make a world of difference in culturing flies. Look at expiration dates of your ingredients, old yeast is bound to give you problems for sure. I understand that price is sometimes a driving factor in today’s market, but a failed culture is a total loss. So finding a source for your ingredients that stocks fresh ingredients is best even if the total cost is a bit higher.
I hope this helps everyone a bit, and sheds some light on the methods needed to culture flies effectively.
Maurice Pudlo
Last edited by MauricesExoticPets; 09-30-2009 at 11:09 AM..
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