Musca domestica should be a widely used and valued live food resource for small amphibians and reptiles but it is not. Our problem has been that the food has been required live and we only had live larvae offered. Live larvae are excellent food for these amimals but the cost to ship them there has been too great. There are times when it is worth it to buy live larvae but they seem too expensive for every day use.
A much better solution is to use live Musca domestica pupae instead of the larvae. Because the pupae is the metamorphosis stage it is much easier to handle. Live pupae can be shipped by ordinary first class mail. It is easy to safely delay the progress of metamorphosis and so hold the insect live in prime condition for several weeks.
Many animals recognise the pupae as a food item and will eat it immediately. Appearing as a small (6 mm), redish, natural pellet the fly pupae can float on water for days. Pupae are UV reflective. At completion of metamorphosis an adult housefly will emerge from the pupae case. Depending upon conditions, humidity and temperature, the newly emerged fly will be a ground dweller for up to several hours while its wings expand and the body stiffens for flight.
During this several hour period the newly emerged fly is probably the best feeder insect commercially available for small animals. From a supply kept quite cold a ration of insects could easily be brought to emergence for daily use.