Culturing Feeder Insects

Culturing Fruit Flies:

D. Melanogaster

1) Place 1/4th heaping cup FNT's Optimized Culture Media into a 32 oz Insect Culture Container (alternatively, flies can be cultured in mason jars using a coffee filter as the lid).

2) Add 1 tbs apple cider vinegar (mold preventative) plus 1/3rd cup filtered, room temperature water. If you are still having mold issues you can use up to 50% vinegar for a few cycles. It won’t hurt the flies but it costs more. Alternatively, 1/8 tsp of methylparaben works like a charm and won’t hurt the flies/frogs, but we have not found it necessary not to use routinely in our cultures.

3) Once mixture is firm, sprinkle 10-20 grains of active dry yeast over the media. The yeast will help process the media and will out-compete molds growing on the surface.

4) Add excelsior or doubled up coffee filter (hint: if using filters, prop up against sides of container. Do not let touch media).

5) Add 20-30 flies. Using the first flies to hatch from a culture to seed a new culture helps maintain the colony by selecting for the healthiest flies and prevents mites (see below)

• Depending on temperature and moisture content, new flies will hatch in approx 10-20 days.

• Culture media should remain moist but not runny. You may need to add more or less water to the cultures based on humidity levels (more water can always be added later if cultures begin to dry. Vise versa add a little more media on top if runny).

• Promptly discard any moldy cultures or any cultures contaminated by mites or flying flies.

• Start a new batch of cultures at least once a week to ensure continued production. One 32 oz culture/wk is generally sufficient for 2-4 adult frogs.

• Prior to feeding, dump flies into a secondary container and dust with 1:1 calcium/D3:vitamin supplements. We recommend Repashy Calcium PlusDendrocare,  or a 1:1 mix of Repashy Supercal medium D and Supervite. Please adhere to supplement expiration dates as potency declines over time.

D. Hydei

• Use directions for D. Melanogaster above, EXCEPT: a) Double the recipe (1/2 cup media) and b) use excelsior not coffee filters as they won’t hold up to weight of flies.

Preventing Mites

Mites are everywhere. They are going to get into your frog room, tanks and eventually cultures (they can fit through the lid fabric). So, how can you keep them out of your insect cultures? Follow these tips and they won’t be a problem even if they manage to find their way into a culture:

1) Always check cultures for mites, and discard any contaminated cultures immediately. However this shouldn’t happen if you follow the following.

2) Always use the newest (and preferably never opened) producing cultures to seed new ones. This is especially effective with melanogaster as the life cycle of melanos is much shorter than the mites. Thus, seeding a new culture as soon as flies emerge does not give any contaminating mites enough time to reproduce.

3) Keep cultures inside a secondary container that is lined with mite paper. To make your own mite paper, spray paper towels with miticide and let dry. We use pyrethrin/piperanyl butoxide based mite and lice spray. There are also “all natural” formulations available, but we have not tested their effectiveness. Keep in mind that “natural” or “organic” formulations are not necessarily safer than the synthetic insecticides. Case in point: batrachotoxin (dart frog toxin) is 100% natural/organic. Secondary containers can alternatively be lined with diatomaceous earth.

4) Keep older cultures in separate containers than new ones.

5) DISCARDING CULTURES WITHIN ONE MONTH is most effective way to prevent mites from hatching and causing issues.


Culturing Springtails (Collembola)

There are many methods for culturing springtails. Common substrates range from charcoal, peat, wood chips, coconut bark, clay etc. Commonly used foods include flake food, mushrooms and yeast. After trying numerous variations and combinations of these substrates/foods, we find that the following to be easy, cheap, and to work equivalently or better than the other approaches.

1) Soak hardwood wood chips in dechlorinated water and microwave to a boil.

2) Let cool to room temperature.

3) Decant excess water.

4) Fill a tight sealing container 1/2 way with chips. No ventilation is needed is culture is opened to exchange air 2x/wk.

5) Add springtails to seed culture.

6) Feed with a pinch of springtail food 2x per week. Alternatively, the springtails thrive on reconstituted dried mushrooms. We do NOT recommend using fresh mushrooms as this is likely to introduce mites into the culture eventually.


Culturing Bean Beetles/Weevils (Callosobruchus maculatus) 

Bean beetles are extremely easy to culture. Their larger size and prolific production make them a great alternative to D. Hydei.

1) Place ~2 inches black eyed beans in the bottom of a 32 oz Insect Culture Container.

2) Add ~30 beetles.

• No water or food (other than the beans) is needed!!

• Beetles will lay eggs on beans. Once eggs hatch, larva will bore through beans and emerge as adults in ~ 2 months. Adults do not eat.

• A simple way to dispense beetles for feeding frogs: Remove the paper mesh from the lid of a 32 oz Insect Culture Container. Cover the holes using ¼ inch wire mesh. Put this lid on a culture from which you want to feed, and simply shake the beetles through the lid. The mesh will trap the beans in the container.