In our lab, we use the following recipe:

Distilled Water - 16L

Malt - 720g

Corn Meal - 850g

Agar - 90g

Soy Flour - 156g

Yeast - 270g

Corn Syrup - 1.2L

Mix the corn meal and agar and add about 2-4 L of the water to make a slurry -- mix well (this is important, as it helps prevent clumps from forming during the heating step). I typically add all the ingredients into the vat and stir before turning on the steam. Heat for 10 minutes under a constant stir, and make sure to adjust the steam valve accordingly if the mixture starts to boil over. Turn off the heat after the 10 minutes are up, cover the vat and let it stir for about 1 hour. Sometime before the hour is up, add 10g of Tegosept to 40mL of 95% ethanol and dissolve completely, and measure out 76mL of propionic acid. Add these to the food mixture at the conclusion of the hour, add an additional 500mL of water, stir well, and dispense into vials/bottles. This is good for making about 10-12 trays of 100 vials each, and can be scaled up or down depending on your needs. I find that the food comes out wonderfully if these instructions are followed, and lasts quite a while longer, too (especially if trays of vials are kept in plastic bags for storage with a moistened paper towel inside). I find that the biggest mistake is not adding enough water, which often results in food that pulls away from the sides of the vials after a relatively short period of time. Good luck!

Dear Frank, Thanks a lot for sharing your experience! 

We make standard fly food medium in our lab. I don't have the recipe on me, but the recipe above is about right. I think some of the common mistakes that people do are as follows:

- not accounting for water that also evaporates

- putting in the food preservative at the correct temperature

- being fast at pouring fly food into vials (sometimes, the food coagulates faster than expected, which ends up causing the vials to be uneven in food distribution, which can be a problem in some cases)

For recipes and tips for cooking food for Drosophila see in:

Kekić V. and Pavković-Lučić S: 2003. Fruit and vegetable food media suitable for maintaining Drosophila melanogaster flies. Drosophila Information Service 86: 147.

Hi Indrikis, there are lots of recipes in the Markow and O'Grady book.  We use three main recipes - the 'Tucson' recipe (the recipe used by the old Tucson stock centre... basically fly prison food), the standard cornmeal-molasses medium used by Bloomington and (for multi-species comparisons and to make sure there isn't anything food-limiting for experiments) a Banana-based food, since everything grows well on it, even if it is a bit more expensive and a bit of a pain to make.  The biggest issues for food making (in our experience - probably thousands of litres over 8 years) are 1) not boiling the food long enough to properly dissolve the agar and 2) pouring the food when it is too hot, which means it can separate (solids at the bottom, agar on top)... wait until it is 70 degC... but not too much longer, as Amanda points out!  If you are hiring an undergrad to help out, the best question to ask is whether they bake (note: not cook!  baking is precise and doesn't work if you don't follow the instructions... cooking is a bit more fluid...).  Bakers make the best fly food chefs (and also molecular biologists).  Hope that helps, b

Dear Indrikis, 

I just use over-ripe banana mush. 

All the best, Anders

Standard 'Glasgow' Food Recipe

(Also used in labs in Brandeis, Toronto, Oxford etc.)

Glasgow ASU Media Services Fly Food Recipe and Protocol

• 5L hot tap water into pot. • Add:- 100G Taiyo Agar 10TblSps Soya Flour 150G Sucrose 330G Glucose 150G Maize Meal 100G Wheat Germ • Stir these in. • Add a further 2-4L hot tap water to pan (you can add the full 4L now or split it into 2L now, 2L later, the important thing is the final volume of water reached should be 10L). • Bring 1L of tap water to boil in kettle. • Pour into separate pan and add 330G Treacle. Melt treacle in boiling water. • Stir in 350G Activated Dried Yeast to the melted Treacle. • Add Treacle/Yeast Soln to the main pot and stir in. • If you haven’t already done so, add the final 2L tap water to pot (final volume therefore ~10L). • Heat Fly Food to between 90º - 95ºc, stirring mixture. • Once a temp of 90º - 95ºc is reached, stop heating and allow Fly Food to cool to 70ºc. Do not let the temperature exceed 95ºc as this may cause the food to ‘split’. • Once Fly Food is at 70ºc add 100mL Nipagin and 50mL Propionic Acid. • Allow to cool to 65ºc. Do not add the Nipagin/Propionic Acid before the food has cooled to 70ºc. • Dispense as required. • Do not let the food cool below 65ºc when dispensing as this may then causes clogging in the dispenser and uneven food distribution.

Food composition for Drosophila is not trivial and can also influence the behavior of the flies, especially visually guided behavior, e.g. see here:

Conditioned visual flight orientation in Drosophila: dependence on age, practice, and diet.

A Guo, L Li, S Z Xia, C H Feng, R Wolf, and M Heisenberg 1996

It can depend on what you are trying to accomplish. For example the percentage of yeast in the food and the dryness of the food can have a huge impact on larval growth - dry food can lead to slower growth and smaller adult flies. 

If you are planning to do gene switch studies using RU486 or use other drugs such as rapmycin in your research the following chemically defined food by Matt Piper might be of particular use as it allows increased bioavailability of drug, and there is no problem with degradation/breakdown of drug by active yeast.

http://www.nature.com/nmeth/journal/v11/n1/full/nmeth.2731.html

Thank you all very much for the recipes! I have lots of opportunities for manipulations of resource quality now. 

All the best,

Indrikis