To investigate sterol utilization in sawflies, the neutral sterols of four species of sawflies were determined by gas-liquid chromatography and mass spectrometry, and compared to the respective dietary plant material. Cholesterol was the predominant (55-76%) sterol in all species and stages of sawflies examined. Host plants, however, contained primarily sitosterol (50-88%), along with other 24-alkylsterols and only 0.5-5.9% cholesterol, indicating that the sawflies examined are capable of dealkylating the C28 and C29 phytosterols in their diet to cholesterol. Comparative sterol metabolism in Hymenoptera is discussed.