Culturing Fruit Flies

There are two species of fruitflies that are commonly reared and used for feeding small herps. Drosophila melanogaster is the smaller of the two and completes it's life cycle in 2 ½ to 3 weeks. D. hydei is a little larger and takes an additional week or two to complete it's life cycle. They are not as prolific as D. melanogaster but make up for it with their larger size.

When you receive your shipment, carefully unpack the cultures from the shipping box and allow to reach normal room temperature. If the media has shifted during shipping, firmly tap the container down onto a counter top to re-settle it. Most of the adult flies should have survived shipping, however in the rare event that there are no obvious adults the culture will produce more within a couple days as they contain hundreds of larvae and eggs. The cultures should be kept away from temperature extremes as they will breed very slowly when too cold (60's) and become sterile at temperatures at or above 90 degrees. Feeder Cultures of D. hydei and D. melanogaster will produce several thousand flies over a 4-6 week time period. To ensure a steady supply never use all of the adults at one time for food. Always leave some adults in the culture container to continue laying eggs for the next generation.

To feed from the culture, gently but firmly tap the culture down onto a counter top to settle the flies away from the lid. Open the lid and shake some flies into the tank. Continuously tapping the sides of the culture cup will help keep the flies from crawling up the sides until you get the lid back on. Dusting fruit flies with a vitamin or mineral supplement can be done by tapping the flies into a cup containing some of the vitamin/mineral powder and then swirling and gently shaking the flies to coat them. The flies can then be fed in the same way described above.

There are several different types of media that can be used for culturing fruit flies. The instant formula we sell is one of the easiest and most reliable to use. It comes in a powder form that is simply mixed with water and yeast and is ready to use in minutes. It contains anti-oxidants and mold inhibitors- both of which help the cultures to last as long as possible. It is also odorless, allowing you to culture the flies indoors without offending the rest of the family. This type is colored blue to make the larvae more easily visible and is completely harmless to your pet.

It is also very important to make sure that the container used for culturing the flies be cleaned and sterilized between batches. Failure to do so can cause molds, fungi and bacteria to overrun the culture. Using our new disposable culture cups is the fastest and easiest way to be sure your cultures are set up clean.

Culturing Flies using Instant Formula and 32 oz. Disposable Culture Cups
Add ½ cup of dry media to the culture cup
Add ½ cup of water* to the media and swirl to mix thoroughly. A thin layer of water remaining on top of the media just after mixing is normal and will be absorbed as the media solidifies.
Dissolve ¼ teaspoon of dry activated yeast in ½ cup of warm water. Allow it to sit for about 10-15 minutes. Stir the mixture and add about one tablespoon of the mixture to the culture cup trying to get even coverage across the surface of the media.
Once the yeast solution has been absorbed into the media add between 50-100 adult flies to the culture cup and close the lid.
For best results, a loose handful of shredded aspen (Excelsior) can be added to the culture cup to provide more surface area for the flies and achieve greater production.
Place the cultures in an area where they will not be exposed to temperature extremes. Normal room temps. of 70-75 degrees are ideal. Larvae should be evident within a week and new adults will begin hatching in approximately 3 weeks depending on temperature. *NOTE: Adding white vinegar to the water in a ratio of one part vinegar to 4 parts water will significantly reduce the chances of mold growth/contamination.

When culturing D. hydei it is important to wait 7-10 days after the initial hatch of adult flies before using them to start new cultures. This is because the first ones to hatch out are mostly females and the males follow a few days later. Production of D. hydei can be markedly improved by following this rule.The best flies to use for starting new cultures are those from the initial hatching. They are the largest and healthiest flies the culture will produce and will help maintain strong cultures. Waiting until the culture is almost completely spent before starting new ones will result in cultures becoming weaker and weaker.

The use of shredded aspen (Excelsior) also helps to increase yields from the cultures. It provides additional surface area for the flies, keeping them out of the media and potentially drowning.In areas with very low humidity, or during winter in most of the country, the cultures may tend to dry out prematurely. This can be avoided by using a little more water when first starting the cultures or by placing a sheet of cardboard over the lids of the culture cups to reduce the amount of ventilation.Molds and fungi are usually problems encountered when using homemade formulas and tend to be more common during the warm and humid summer months. When a culture becomes infected it should be destroyed. It should not be used for food and never to start new cultures. Using disposable cups will greatly reduce mold incidence.Dissolving the yeast in warm water and evenly distributing it across the surface of the media when starting new cultures will also virtually eliminate any mold problems. This is because the yeast will quickly out-compete any molds before they can get started.

Mites can sometimes wipe out entire cultures in just a few days. Fortunately, this usually only happens when flies are introduced from infected cultures or from wild stock. To prevent this, never use cultures that have been contaminated by wild flies and thoroughly check any cultures before using them to start new ones. Additionally, the use of insecticidal shelf paper will help prevent the spread of mites between cultures.Over time culture production may start to decline due to constant inbreeding of the flies. We recommend acquiring new flies once or twice a year to help keep production strong. When feeding small froglets it is sometimes helpful to keep the flies concentrated in a small area to make them easier to find. An easy way to do this is to place a wedge of orange on a baby food jar lid in the middle of the terrarium. The flies will be attracted to the orange and thus become easy targets. The orange should be replaced out every couple days to prevent it from spoiling in the tank.

Tadpole Propagation

Ultimately, if you keep Dendrobatids, you will eventually come to this topic, so we will attempt to briefly go over some of the important points to successfully breed Dendrobatids in captivity. As far as breeding goes, most Dendrobatids can be broken down, somewhat, into three groups… Ones that will lay eggs in bowers, ones that lay eggs on plants, and Egg-feeders. Many of the larger frogs such as Phyllobates, and Epipedobates, and those in the D. tinctorius group will readily lay eggs in a secluded covered spot called a bower. A bower is anything the frogs can find cover under to carry out their breeding activities. It could be overlapping leaves, a petri dish under a coconut shell, a flowerpot, or a film canister. The male frog usually initiates breeding by calling to a female. If the female is willing, she will follow the male around, stroking his back until he leads her to his bower. This process may take hours. When the eggs are laid, the frogs return to keep them moist. In the wild, the male frog will check on the eggs until they hatch, then carry the tadpoles to a source of water, after which all parental duties end. In captivity, the eggs may be removed at this point to be raised apart from the parents. It generally takes about 8-14 days for the eggs of most species to hatch into tadpoles.

There are many different methods to raising tadpoles. The easiest method is to raise the tadpoles in individual containers until they metamorphose into froglets. Other methods include raising them in groups or using containers floating in an aquarium with a filter to clean the water. We feel that the individual container method is still one of the better methods. Cleaning the water in individual containers can be time consuming, but it reduces the risk of cannibalism or spreading diseases through a group of tadpoles. Once the tadpoles are placed into their individual containers, they can be raised on a diet of high quality tropical fish food. Other items fed to tadpoles include spirulina, chlorella, and mosquito larvae. The water should be changed as it gets dirty, depending on the size of the containers they are being kept in. Obviously, an 8-ounce cup is going to need changing before a 32-ounce cup. The tadpoles should be treated similarly to tropical fish, and similar water quality precautions should be followed, such as treating hard water before using it for the tadpoles. If kept in the mid 70’s, the tadpoles should metamorphose into froglet in about 6 – 8 weeks. Before the tadpole absorbs all of its tail, the water level in the cups should be reduced to avoid drowning. Placing the cup at an angle of less than 30 degrees will also aide in allowing the froglet an easier transition out of the water. Froglets can be managed similarly to adult frogs, except that they are smaller, and so the food items should be adjusted in size, accordingly. Some hobbyists prefer to raise them in smaller enclosures to assure that they can find the food items with ease.

If the frogs are laying the eggs in the provided hut, then life is simple! You just need to remove the lid, or whatever they laid their eggs on, preferably about twenty four hours after they have laid them, (to allow them time to fertilize them) and place the eggs in a container with super high humidity. Before you place the clutch in the humid spot for incubation, clean any debris away from the clutch, and remove any obviously bad eggs with a pair of tweezers, or the corner of a piece of paper towel. Add a small amount of de-chlorinated water, just enough to wet the bottom of the lid or dish the eggs are in. Keep the eggs at around 75 degrees, and you will either begin to see development within a few days, or the eggs will go bad. Many dart frogs do not start out laying good eggs, but may do so after a season or so of bad eggs, but some lay good eggs right from the start.
While the eggs are developing, remove any obviously bad eggs, and keep the clutch damp. After between fourteen and twenty days, the fully developed tadpoles should erupt from the eggs. I assist tadpoles which have erupted, but are having problems getting out of the gel around them, but don't generally break them out of their egg.
At this point set the tadpoles up in a cup with a shallow layer of water in the bottom. The water should be de-chlorinated, or you might consider using spring water, I find the newly setup tadpole to be the most delicate stage of the whole process. Make sure the water is near the same temperature as the tadpole has been, so it doesn't shock the tadpole. If the tadpole seems active you can put a very small amount of good quality flake fish food on the surface of the water, a couple of specks the size of a pepper corn would be about right. You can also wait two or three days before feeding the tad the first time, they do not do much the first few days. As the tadpole begins feeding, water changes every two to five days are required to keep water quality high. You may need to keep a lid on the cup to keep water temps high enough, since evaporative cooling can bring the temperature of water down as much as five degrees. Check the actual water temperature, and keep it in the seventies most if not all the time. The tadpole should emerge at around sixty to eighty days, depending on species, and conditions. When the front legs pop out of their skin, you will want to lower the water level to a quarter inch or so, and stop feeding them. In a few more days you can set up your new frog in a container similar to those I recommend in my froglet care sheet. The new froglets will take their first food within a few days.