Fruit fly moms lay their eggs on everything, from of old produce rotting in your kitchen garbage can, according to the University of Michigan. As is implied by their name, fruit flies most commonly feed on fruit and other sugary substances. Fruit flies are also attracted to the fermenting sugars present in. Calories in Gnat Fruit Fly. Find nutrition facts for Gnat Fruit Fly and over other foods in vpnport.info's food vpnport.infog: house. Nutrition Topics There are two flightless varieties of fruit flies suitable for culturing and feeding to finches: the smaller The entire life cycle (egg->larva->pupa->adult) takes about 11 days at room temperature (a few extra days for D. hydei). Calories in Gnat Fruit Fly. Find nutrition facts for Gnat Fruit Fly and over other foods in vpnport.info's food vpnport.infog: house. I know some people feed Fruit Flies to their ants, but how do you get I have them as pests in my house - first time they are actually useful:D.