drosophila fruit fly culture ingredients

'How to culture Drosophila fruit flies'

To stand a chance of keeping the likes of Poison Dart frogs, Pygmy Chameleons, Praying Mantids or other small insectivores, the art of culturing Drosophila fruit flies is something worth learning about.

There are two commonly available species of Drosophila:

  • D. hydeii (larger but slightly slower to culture)
  • D. melanogaster (smaller with a quicker life cycle)
  • Both can be cultured using this guide, and are available from many livefood suppliers in a "flightless" strain (also known as "vestigial winged"), making them easier to culture and feed to small insectivores.

    Why Drosophila?

    Their small size and ease of culture makes them a big hit with keepers of small insectivores, or breeders with lots of tiny, hungry mouths to feed. Cultures cost next to nothing to set up, and provide hundreds of flies. Unlike crickets of the same size, they don't bite you or your pets, and won't wreak havoc if you have a few escapees. Once you get your own cultures started, you can provide a constant source of nutrition.

    How to start culturing them at home

    Cheap supermarket brands are all you need to get a culture started. The flies and larvae feed on rotting fruit (and yeasts growing on it), and to recreate this, you'll need the following:

  • Disposable plastic drink cups (pint sized or larger)
  • Instant oat cereal (Readybrek or supermarket's own brand)
  • Fresh fruit juice (No need for expensive varieties, orange or apple juice will do!)
  • White wine vinegar
  • Scouring sponges or cotton wool
  • Fine net curtain and elastic bands
  • The 5 steps of setting up a Drosophila culture:

    Each fruit fly culture takes around 2 weeks to "cook", and then supplies flies for 1-2 weeks. After this, any remaining flies should be used to start a fresh culture. If you need a steady supply of Drosophila, it is best to start several fresh cultures every week in advance of when you'll need them. Dart frog and praying mantis breeders can have dozens of cultures running to keep up with high demand.

    Step one: Take a plastic drink cup, preferably pint sized or larger, and add a layer of instant oat cereal (a supermarket's own brand version of Readybrek will do, the flies aren't fussy), roughly an inch deep.
    Step two: Mix in fruit juice to form a paste with a similar consistency to thick yoghurt. This will be the "rotting fruit" imitation which the flies will lay the eggs on and the larvae will eat.

    Of course, we don't want it to smell rotten, or for fungus and mould to grow on the paste, so add 1 or 2 tablespoons of white wine vinegar. This doesn't bother the flies or the larvae, but stops the culture going sour.
    Step three: Place a clean scouring pad, or a small pile of cotton wool on top of the paste. This provides a space for the flies to climb on, and also for the larvae to burrow into and pupate.

    Don't completely cover the paste with the sponge or cotton, as the flies will need to access it to lay eggs. As you can see from the photographs, a folded up scouring pad does the job nicely!
    Step four: Cut a square of fine netting material to fit over the top of the cup. I use voile for this purpose, as both the larvae and the flies are extremely small. This allows some ventilation into the cup, and can be secured in place with an elastic band.

    A small hole around 1cm in size can be cut in the netting to allow an access hole for adding/removing flies. Once the adult flies are in, I plug it with a piece of sponge to prevent escapes.
    Step five:Add 50+ adult flies through the access hole in the lid using a pooter, and replace the sponge plug. After about a week you should see small maggots in the paste, which will then form casters and hatch into flies after approximately two weeks.

    Keeping the culture in a warm place will speed up the process. After a couple of weeks, transfer any adult flies to a fresh culture to keep the cycle going.

    If you have any questions on breeding Drosophila or other feeder insects, feel free to contact me:
    Paul Edmondson

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