I do dust my fruit flies with vitamin/calcium powers. I do this by taking a funnel and placing it in a vial that already has the powder in it. It also helps if the powder is covering all the inside surfaces of this vial, this usually keeps them from climbing out right away. To add the fruit flies I shake the jar or vial of flies into the funnel with one hand and I shake the funnel/receiving vial with the other hand. After dusting, I give the flies to my frogs.
To culture flies you will need media mix, jar or vials, and something like excelsior for them to climb on. These items can all be purchased at Black Jungle, along with the flies themselves. Mix the media with boiled distilled water according to directions on the package, put the mixture in your jar(s) or vial (s), let cool then sprinkle baker's yeast on the media. Add some excelsior to the jars and then add the flies. Depending on what speices of fruit fly you use, it will take from ten to sixteen days before you begin to see results. Drosophila melanogaster, the smaller of the two commonly sold flies take less time to show results than does D. hydei. However, hydei is a larger fly than melanogaster.
To keep the flies in the enclosure with the frogs I use an enclosre that will allow me to place a paper towel in between the top and the rest of the cage. Critter Keepers are great for this, at least the ones that don't have vents on the sides are. The paper towel allows for ventilation, and even allows for the passing of water.
Any questions?