Lipid requirements of the larva of the housefly Musca vicina (Macq.) reared under non-aseptic conditions.

Up to the present, no nutritional studies of the genus Musca have been made, despite the fact that M. dome8tica is extensively used for the laboratory testing of insecticides, and that in recent years, with the development of resistance to insecticides, the importance of physiological studies of the housefly has increased. In general, the nutritional requirements of insects for lipids are mostly restricted to the unsaponifiable fraction (Scoggin & Tauber, 1950), although the saponifiable fraction (fatty acids) has been shown by Fraenkel & Blewett (1947) andbyPepper & Hastings (1943) to be related to normal growth, wing development, diapause and sterility. The part played by the sterols in the nutritional requirements of several insects has been studied under non-sterile conditions; blowfly larvae by Hobson (1935) and Dermestes, Tribolium, Lasioderma, Silvanuws, Ptinuw and Ephestia by Fraenkel & Blewett (1943). As far as is known, bacteria neither synthesize nor require sterols (Deuel, 1951), although some yeasts contain phytosterol. Our own experiments preliminary to the present work indicated that the bacterial flora of our laboratory-bred housefly failed to make good the nutritional deficiencies suffered by the larvae when reared on a fat-free diet. With this information, an investigation was undertaken into the lipid requirements ofM. vicina. Some of the results of our work have already been reported briefly in a preliminary note (Bergmann & Levinson, 1954).