The effect of dietary cholesterol on the development of Hylemya brassicae

The influence of different concentrations of cholesterol upon the larval and postlarval development of Hylemya brassicae has been investigated using an artificial diet and axenic culture conditions.In contrast with other insects studied, H. brassicae larvae are extremely sensitive to cholesterol, even in minute concentrations, until after their second ecdysis. Concentrations of 0.1 to 0.$\text{4}$g/100 ml disturb the second moulting process in a typical way that could indicate an endocrine unbalance and result in a very high mortality during this process. When cholesterol at a concentration of 0.4g/100 ml is administered to the larvae after the second ecdysis, there is no longer an adverse effect on the further larval and postlarval development.The unusual sensitivity of young cabbage root fly larvae for cholesterol seems to point out some significant differences in the sterol requirements and metabolism of the species in comparison with other insects studied.