Standard Banana/Molasses Media

Used for most species including D. mojavensis, D. arizonae, and D. navojoa. 

Each liter of input water makes ~100 10mL vials after boil-off.

We use narrow 8 dram glass vials as their better water retention helps food to last with the 4 week generation time.

We use a large portable gas stove which works best with at least a 4 liter cook.

Can be done in smaller amounts on a hot plate but food consistency is not as good.

Adjust agar amount based on the gel strength of each agar bucket. We use Nutri-Fly Drosophila Agar from Genesee Scientific.

Ingredients per Liter of Water

To Cook:

Must stir continuously throughout, we use a powered stirrer.

1. Add DI water to pot and slowly stir in agar.
2. Let the water reach a rolling boil and reduce heat to prevent boiling over but keep at a boil for 15 minutes.
3. Blend bananas with some of the extra water in a blender till smooth.
4. Add corn syrup and molasses to bender and mix.
5. With the bender running add the yeast.
6. Add banana mix to the pot and cook for 15 minutes. Increase the heat enough for it to boil again though watch for over boil as it rises quickly once it starts.
7. After 15 minutes most of the foam should be gone if not cook longer.
8. Place in a sink with ice water to help cool.
9. Dissolve Methylparaben in 95% ethanol.
10. When the food reaches 54°C, mix in methylparaben solution.
11. Place on a hot plate on low to keep warm.
12. We use a peristaltic pump to distribute the media into vial.
13. Cover vials with cheesecloth and let cool.
14. Seal the vials with film and place at 4°C overnight.
15. Add a few grains of yeast and add flugs to the vials.

If sealed with film (Flystuff Geneseal) vials will last for at least 2 months though can last longer. Unsealed best to use within a month.

Media can be frozen and melted several times though quality will degrade.

Genesee's Droso-Filler can work with our media but tends to clog more and give less consistent results than with cornmeal based media.

Potato Media

Used for Saguaro breeding flies such as D. mettleri and D. nigrospiracula also works well for the South American species.

Easy to make a handful of vials by scaling down, though slow for making large amounts. Best to be made fresh and used the same day. It does not keep well in the fridge.

Ingredients per Liter of Water

1. Add yeast and water to a pot and boil for 15 minutes, sir enough to prevent settling.
2. Let cool to room temperature. The killed yeast can be stored at 4°C for several months in a sealed bottle.
3. Make the methylparaben solution by dissolving the methylparaben in 95% ETOH.
4. Add the solution to the killed yeast.
5. For each vial individually add ~1.85 grams of plain potato flakes.
6. Add ~10mL of the yeast mixture to the flakes and let sit until fully absorbed.

Media should be slightly wet when finished if it is dry add more yeast mixture.

This media is less dependable than the banana/molasses media and tends to have more population crashes. Should only be used on flies that don't tolerate banana/molasses.

Molasses Cornmeal Media

A rich cornmeal media adapted from Todd Schlenke's lab recipe.

Works well for D. hamatofila and D. anceps. Most D. arizonae and D. mojavensis stocks will also work on this media but not as well as Banana/Molasses. Can also be used for difficult D. melanogaster stocks as well as species in the suzukii group.

Ingredients per Liter of Water

To Cook:

1. Measure out agar, sugar, yeast, and cornmeal and mix together. Add the DI water to this mixture.

2. Stir continuously, heat until a good simmer does not need to boil. Let simmer for at least 30 minutes until it is thick and the corn meal stays in solution.

3. Mix the extra DI water and molasses together and add to the pot. Let simmer another 15 minutes.

4. Dissolve Methylparaben in 95% ethanol.

5. Cool to around 58°C best to let cool slowly not on ice.

6. Add dissolved Methylparaben and Propionic acid.

7. Put in vials.

If media doesn't solidify well the cook time was likely too short.

This recipe works well in small batches on a hot plate with the amount scaled to 0.7L for a 1L beaker.

Unlike Banana/Molasses this does not remelt multiple times very well and the texture will start to change after a couple rounds of use.

Most species that like this media will also like a piece of Kimwipe in the vial for more surface area.