To set up the mating crosses, place the Bradysia coprophila adult male flies on a white fly pad. Use fine tipped forceps to gently pick up the fattest adult by its middle or hind leg. Then place the anesthetized adult female flies on a white fly pad.
Using fine tipped forceps, pick up an adult female by its hind leg. One day after mating, push the wings of the anesthetized adult females into 2.2%agar in a Petri plate. Once all the female flies are impaled on the agar, gently squeeze the thorax with forceps.
The female will lay a cluster of fertilized eggs within 30 to 60 minutes. Use a dissecting microscope to score the newly emerged larvae. Observe the inch worm-like motion of the newly emerged larvae as they crawl on the surface of the 2.2%agar.
After removing the vial plug, examine the vial for the age and number of larvae. Pick up some straw between the second and third fingers or between the thumb and second fingers, and rotate the fingers against each other to deposit the appropriate amount of straw into the vial. On the same day that the larvae emerged, or up to two days later, sprinkle in a tiny bit of food that has been poured into a small bowl for easier access, and replace the gauze plug.
For one week old larvae, add more food to just cover the surface of the agar and replace the gauze plug. For the two week old larvae, sprinkle in a generous amount of food to cover the agar surface and replace the gauze plug. Once the larvae attain the late fourth instar stage and begin to pupate, add a generous amount of food on the agar surface.
Stop feeding once adults begin to emerge. Do not feed vials with adult flies and do not remove the gauze plug. If there is white mold in the vial, use 70%ethanol on a laboratory wipe to clean a long metal probe.
Insert the clean probe into the vial to tap down the mold on the surface of the agar. Then clean the probe with a laboratory wipe dampened with 70%ethanol before storing or using it on another vial. Add only a small amount of food without disturbing the top of the agar, and replace the plug.
