Making fruit fly cultures is part of the weekly ritual of keeping dart frogs. Culturing fruit flies sometimes feels like more of an art than a science. Keeping track of what media to use, the right environment, and what supplies to purchase can seem overwhelming. This is true specially for a newer hobbyist, luckily as you get used to it it is not too bad. In this article we will review some crucial supplies and steps to help you successfully culture fruit flies! Even if you are an expert fly keeper I’m sure there will be some new or interesting information in this article.
Supplies needed for culturing fruit flies
Although there are many supplies you can use to culture flies, all you really need to start are cups, fabric or vented lids, excelsior or an alternative substrate, and media.
Most hobbyists buy quart sized plastic containers to house their cultures with many buying from restaurant depots or wholesalers. I usually buy containers and lids from superiorshippingsupplies.com. The benefit of buying from this vendor is that they also sell fabric lids in large quantities. Refer to the table below to find out where I buy most of my fruit fly culturing supplies from.
Packing paper on the left in a fruit fly culture. Bulk excelsior on the right.
Excelsior vs. Packing Paper – What is the best substrate for fruit fly cultures?
Another key item to buy to culture fruit flies is the substrate in which the flies live, mature, and lay eggs in. There are a few different types of substrates you can use for your fruit fly cultures including excelsior, packing paper, or coffee filters. These substrates provide surface area for flies to move around on, breed, and for larvae to pupate on. When looking for a substrate to culture fruit flies, it is crucial to pick something that is resilient and provides a lot of surface area.
My go to options are excelsior or packing paper used to pack glass objects. Both of these provide an immense amount of surface area while also being affordable. Another alternative is using coffee filters, these may work but I have never had much success with them personally. Whatever substrate you use for fruit fly cultures it is important to pack enough in the media to provide as much surface area for the flies to live on and breed in. These days I have been using packing paper more because it is cleaner, cheaper, and easier to use. I do occasionally switch things up as I have always had success using excelsior in my cultures.
What media to use to culture fruit flies
One of the most important parts to culturing fruit flies is selecting an appropriate media. There are many different types of commercial medias available as well as DIY recipes you can find online. Your mileage with different medias may vary and what works for one hobbyist may not for you.
I personally have tried making my own, FrogDaddy’s Gold formula, Repashy, and Josh’s Frogs over my time keeping frogs. Making your own may end up being the cheapest, but different recipes have varied yields. I personally use Frog Daddy’s Gold media for all my drosophila melanogaster cultures and Repashy for my hydei.
Overall, FrogDaddy’s is my favorite to use since you do not have to boil water. Additionally, this media provides huge booms for melanogaster and Alex ships out bulk media. For hydei cultures, I find that Repashy lasts the longest, gives me the best yields, and is the most affordable. Be sure to try out different cultures to see what you prefer, each has its own benefit and can produce great yields.
I use repashy superfly (left) for all my hydei cultures. I add paracoccus powder (right) to add extra carotenoids to the cultures.
How to improve your fruit fly cultures – Carotenoids and other additives
When preparing cultures its not uncommon to add in different supplements or agents to help maintain the health of the culture. For my hydei cultures, I often add in vinegar to prevent mold, carotenoids, and cinnamon for the smell and supposed antimicrobial properties (mainly for the smell). I find hydei cultures usually need a bit more care if using repashy, vinegar is almost a must for me to curb some of the mold issues I’ve seen.
For all my cultures I have experimented with various carotenoids to help ensure my frogs have better coloration. Currently I am trying Paracoccus Powder (Astaxanthin Powder) from Brine Shrimp Direct, also available from Bulk Reef Supply. I have also tried repashy SuperPig with some success. The idea with adding in additional carotenoids into cultures is to provide more available to your frogs by “gut loading” the fly. I have noticed that the flies and maggots always have more red in their stomach when reared in a culture with these extra carotenoids. Its hard to isolate the effect of this as I also dust my flies with carotenoids at every feeding.
Potential additives like vinegar, cinnamon, or carotenoids are not essential for your cultures, but can help with potential problems that may come up in your cultures or provide your frogs with additional nutrition.
One of my hydei cultures to the right with excelsior compared to a melanogaster culture with packing paper. You can really see how much substrate I jam into these cultures.
What type of fruit flies are best for poison dart frogs
As I alluded to earlier, there are two types of flies I keep, wingless drosophila melanogaster and flightless drosophila hydei. Typically I feed melanogaster to all my small to medium frogs including epipedobates tricolor, ranitomeya, dendrobates tinctorius, dendrobates leucomelas, and oophaga pumilio. I use hydei for my medium to large size frogs such as my dendrobates tinctorius, phyllobates terribilis, oophaga histrionica, and sometimes my oophaga pumilio. The key differences between the two is melanogaster is smaller with no wings while hydei are larger and also can carry more supplement dust on their wings.
FrogDaddy has recently released a flightless variant of drosophila melanogaster dubbed ‘creamsicle’ that has wings (seen on the left). The advantage over wingless flies is that these can carry extra supplements/dust on their wings to your frogs.
Comparison of flightless melanogaster (left) vs. hydei (right). In person the melanogaster is clearly smaller around the same size as a normal melanogaster.
Best environmental conditions for culturing fruit flies for dart frogs
Keeping a stable environment for fruit flies is often the trickiest part of ensuring cultures thrive and boom regularly. Both melanogaster and hydei typically produce flies quicker depending on how hot their environment is. The optimal temperature to keep melanogaster is 76-78 degrees with humidity levels around 60%. It should be noted that flightless flies with wings such as hydei may start flying if kept >80 degrees. Higher temperatures can reduce the lifespan of cultures and increase mold growth. I have seen the best yields keeping flies on top of my rack with temperatures around 72-75 degrees.
Humidity is another crucial factor to ensuring your success when culturing fruit flies. If the cultures have too much moisture, it can kill flies and reduce the health of the culture. If it is too dry the flies will not be able to reproduce and the maggots and larvae will die. During the Michigan winters I have trouble keeping humidity up and have used plastic totes, but this last winter I have used 10×20 plant trays with humidity domes to keep things at the right levels.
Don’t be afraid to move your cultures around and see how they do in different locations. I still tweak my setups and change things around depending on how my cultures are doing.
How to prevent pests in fruit fly cultures
The enemy of every dart frog hobbyist and fruit fly culture are grain mites. These small white mites are almost impossible to get rid of in cultures as they exist on the flies themselves. They have the potential of crashing cultures, reducing yield, and infesting other cultures. Thankfully there are a few ways to prevent and combat these mites.
Tips and tricks to prevent pests when making fruit fly cultures
- USE DIATOMACEOUS EARTH OR MITE PAPER
- This is the number 1 thing you can do to reduce the spread of mites. All my culture trays have a layer of diatomaceous earth which all the cultures sit on. I honestly prefer using mite paper since it is cleaner, however, you do have to change it out more frequently. Because of this and the amount of cultures I do I have gone back to using diatomaceous earth in all my culture tray
- Throw out cultures older than 30 days
- I typically toss my melanogaster cultures after 30 days, but I do hold onto my hydei as they usually take longer to get up and running and produce for longer. I always date my cultures so I am sure to know their age and whether I should consider tossing them.
- Separate older cultures and newer cultures
- I have a new 10×20 tray for each set of cultures I make every week so that older cultures never come in contact with newer cultures
- When seeding cultures add in some calcium powder to knock off mites
- I have heard other hobbyists suggest this and I typically add in some expired calcium powder or carotenoids to the initial group of flies. I then ensure they are coated and try to just tip the flies into the new culture while leaving behind the left over dust.
- If feeding from older cultures and newer cultures use the newer cultures first or use hand sanitizer between cultures
- This tip is borderline obsessive, but mites do get transferred from your hands. I usually use some of my newer cultures before getting the last bit of flies out of an older culture.
If you use at least a few of these techniques and tips you will be sure to reduce the amount of mites and curb potential outbreaks in your cultures.
Conclusion
Culturing fruit flies for your dart frogs is the single most important thing to keeping them alive. Although a constant chore, culturing flies can be easy if done on a regular schedule. It is no surprise many people recommend culturing flies for a few weeks before getting their first flies, nor is it a surprise that most people who downsize their collection blame culturing flies as a contributing factor.
By keeping a schedule and routine this task becomes pretty mundane and easy to do. I usually spend around 15-30 min making 8-9 cultures a week. Following some of the tips presented in this article like using packing paper, specific media, and pest prevention like diatomaceous earth should help you get on the right track and streamline your fruit fly culturing journey!
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