Species Profile
Housing
Feeding
Behaviour and Biology
Reproduction
Troubleshooting

Common name: Vinegar fly, fruit fly.
Scientific name: Drosophila melanogaster
Size: 2.5mm long
Lifespan: 21 days approx
Diet: Detritivore; decaying fruit and vegetable matter.
Appearance: Tiny flies with red eyes. Varieties from labs and within the hobby exist with vestigial wings, making the flies flightless.
Use in hobby: Feeder insect for small fish, birds, frogs and invertebrates.

Our recommended size: 425ml cup or jar with a vented/filtered tight fitting lid. Ventilation may be filter paper, cloth or fine mesh. Solid lids should have pin holes to allow air flow.

Temperature: Keep out of direct sunlight. 24C is most ideal. Above 28C causes flightless gene reversion, and below 18C often causes failure to thrive. 

Substrate: 2cm thick layer of a fruit fly food mix. You can buy premade lab mixes, use our recipe or use your own recipe from online. Fruit fly larvae feed and grow in the substrate.

Decor: Excelsior (wood wool), folded coffee filters or shredded paper for adult flies to grip onto. Not a lot is needed. Our cultures are shipped over-packed for safety in transit. 

Maintenance: Little maintenance is needed after set up, just keep cultures in ideal temperatures. New cultures produce new flies after two weeks. To continue maintaining fruit flies for your animals to eat, start up and keep multiple cultures when your original cultures are producing flies at their peak. 

• Place the food substrate into the container first. Add fresh new wood wool or shredded paper before shaking in about 20-50 adult flies to start the culture. It takes several days for larvae to appear, read on below for more detail on reproduction. 
  
• After a culture is 4 weeks old, clean out the culture. Avoid keeping cultures older than 4 weeks to prevent grain mite infestations.
  

The purpose of raising fruit flies is to feed small animals. Harvest the flies when they start emerging from their pupae in large numbers. The following technique can be used to move flies into newly set up cultures.

1. To harvest, tap the upright culture cup on the table liberally to dislodge flies from the top and sides to avoid escapees. 
2. Remove the lid quickly, keep tapping the cup if the flies try to climb up.
3. Angle and tap the cap directly over the enclosure of the animal you wish to feed, and the flies will fall in. 
4. Re-apply the lid as soon as possible to avoid escapees and contamination from wild, flying fruit flies.

There are several species of fruit fly in the world. Drosophila melanogaster is a very common species. For many people, these flies are seen as a pest around old fruit and vegetable. They generally are only a pest in the presence of old, rotting food. These are not to be mistaken with other fruit fly species such as Mediterranean Fruit Fly. 

In captivity, drosophila melanogaster is commonly used for studies in labs due to their short lifespan, ease of breeding and genetic selection. Due to this, vestigial wing (small reduced wing) and other varieties exist. This has made it easier to handle these flies, both for scientists and hobbyists!

Sexing drosophila melanogaster is normally not needed when breeding, as shipped cultures are started with 50-100 flies usually (at home you only need 20 flies to create a bumper culture). It is quite easy to tell apart males and females, as they are sexually dimorphic. Males have shorter abdomens and have a distinct black patch on the end of the abdomen.

The reproduction of drosophila melanogaster is well studied, their sexual preferences and biological development are extremely detailed in knowledge, but we will cover only the basics we need to know as hobbyists.

Handy Tip: Label the date of when a culture was started on the container. This will help you keep track of multiple colonies and how they are doing!

1. The life cycle of a single fly usually plays out for about 21 days, from egg to death. In warmer temperatures this may be faster, and in cooler temperatures much slower. In winter, you may need to heat your cultures.
   
   
2. The female fly can lay up to 100 eggs a day, and will do so into the nutrient rich substrate.
   
   
3. After 12 hours or so, the eggs hatch into tiny larvae and feed on the substrate, burrowing through it.
   
   
4. Over time the larvae grow larger and larger, usually between 7-10 days afterwards.
   
   
5. Mature larvae leave the substrate, climbing into surfaces to pupate. In a culture, they can be seen on the sides of the cup as rice-like pupa.
   
   
6. After 4-7 more days, adult flies emerge from the pupae and a noticeable population spike occurs.
   
   
7. Adult flies generally die within 7 days of emerging, so it is best to start new cultures once a culture starts to produce flies. The old substrate cannot be reused, it is no longer suitable for new larvae to grow in.

Grain Mites

Grain mites are a natural occurrence in all Australian flightless fruit fly cultures. These are typically not an issue unless you keep a culture over 4 weeks old, and do not clean out and remove old cultures. When grain mites overpopulate, they can out-compete the fruit flies and cause cultures to fail. Practice good culture hygiene, clean out old cultures and occasionally wipe down the area where fruit fly cultures are stored. 

Other mites and pests

Foreign mite species, ants and wild flies might be attracted to fruit fly cultures as a food source. Avoid pest problems by practicing the following:

• Keep cultures indoors in a space away from potential pests (such as a cabinet away from open food sources). 
• Add extra barriers against pests such as anti-mite paper, diatomaceous earth, mesh screens, or non-woven poly fabrics. 
• Avoid opening cultures where wild flies are present. 

My culture isn’t doing much and/or is growing mold!

The biggest culprit for cultures going stagnant is temperature. Keep temperatures consistently above 18C, though 24C yields the best results! You may need to provide your culture with additional heating. This is best done via heat lamp, cord or mat connected to a thermostat in an enclosed space. 

What happens if my vestigial wing flies have started to develop flying wings?

If your cultures have started to develop full wings and flying, it may indicate one of two things:

• The temperature of the culture has reached 28C+ at some point, increasing chances of genetic change back to flying form. Keep cultures in a cooler room, and use air conditioning when necessary.
• Wild fruit flies have gotten into the culture due to it being near a wild source of flies eg. if kept in the same room as some old fruit, or near a window. 

Once a culture has been contaminated by fully winged fruit flies, it is best to discard the culture, find out and eliminate the cause, and then purchase a new flightless culture from a reliable source if you don’t have any untouched back up cultures.