Nitrogenase Activity in the Queensland Fruit Fly, Dacus tryoni

Abstract

When 5-day-old laboratory-raised Queensland fruit flies (Dacus tryoni) were fed a dinitrogen-fixing bacterial strain of Klebsiella oxytoca isolated from the crop of a wild fly, acetylene reduction (nitrogenase) activity associated with the flies was detected after 2 to 3 days and persisted for at least 22 days. Flies not fed the dinitrogen-fixing strain were negative for acetylene reduction until 21 days after emergence. Presumably such dinitrogen-fixing bacteria are able to supply some Queensland fruit flies with a small part of their nitrogen requirements, but its importance is unknown.