CULTURING FRUIT FLIES – Drosophila
WRITTEN BY D.KNIGHT
Fruit flies are a great staple diet for frogs such as Dendrobates, and make a great starting diet for froglets of all species. They are very easy to culture and can save lots of money, along with providing a constant fresh supply of food.
To start a fruit fly culture you will need the following
A starter culture which you can purchase online or pick up in your local rep store
A selection of jam/coffee jars or suitable containers
A mixing bowl
A supplement powder
A large container
A tea strainer
Some old tights
A set of scales
Straw/cotton wool/paper towels/wood wool
And the ingredients to make the culturing media.
For this you will need
Pure fruit juice
Instant potato (flakes preferably)
The first thing you need to do is measure the ingredients into the required amounts. The easiest way to do this is to use the scales and use a selected weight as 0ne part and then use this accordingly. For example if one part is 10 grams the four parts would be 40 grams.
Mix one part white sugar, half a part brewers yeast, four parts powdered/instant milk and four parts instant potato. Once this is thoroughly mixed together add a splash of white vinegar and slowly add the pure fruit juice. It is important that the mixture does not become a liquid, it needs to be consistent, and more like a slightly wet cake mixture. Once the media is complete you then need to fill the jars. In a large coffee jar the media should be around ¾ of an inch deep, this should be adjusted accordingly depending on the size of the jar/container. The best method to add the media is to place a funnel into the top of the jar and simple pour the required amount in. Once the media is added the lids need to be constructed. This can be done one of two ways, the first is to use an old pair of tights or fine netting, Cut a suitable sized piece (if using tights it is wise to make it two layers thick) and then pull over the top of the jar/container. Once it is stretched over simple hold in place with an elastic band. The second method is very similar except the tights or fine mesh is held in place by the lid, which needs to have the middle cut out so that it is just the thread with a slight shoulder. After the media is added and the lid is emplace the media should then be allowed to set for at least 12 hours.
ADDING THE FLIES
After the media has been allowed to stand the flies can then be added. First thing to do is to remove the lids and give the mixture a gentle stir, this will help release the gasses from the yeast and will also give you an indication on the quality of the media. If the media has become too thick then fruit juice can be added accordingly to supple it back to its required state. After you have released the gasses and checked the media you need to add either some Straw/cotton wool/paper towels/wood wool to act as egg laying and climbing sites. This should not be too thick but dense enough to allow plenty of space. The final stage is to add the flies. Around 30-40 should be added per jar, a common reason for cultures to fail is insufficient flies being initially added. Fruit flies cannot fly but are great climbers and this method will help to reduce the number of escapees. In a large container add two table spoons of your chosen vitamin supplement and then tip the flies from the starter culture directly onto it. Give the container a gentle shake then tip the flies and the powder through a strainer, releasing the supplement but holding the flies. It is then just a case of placing the flies in the jars and putting the lids back on.
STORAGE and CARE
The flies need to be kept between 70 and 79 degrees, the higher the temperature the faster the life cycle will be. It is a good idea to do six jars, created in batches of twos, several days apart. This way there will always be some incubating, some breeding and some ready to be used. After six to eight weeks it is also advisable to throw all the flies away and start again. It is possible to keep one of the last jars as the starter culture for the next time around, yet again saving money and never running out of your frog’s favourite food.