Svoboda, J.A., Insect Physiology Laboratory Plant Protection Institute, ARS, USDA, Beltsville, 20705, Maryland, United States
Dutky, S.R., Insect Physiology Laboratory Plant Protection Institute, ARS, USDA, Beltsville, 20705, Maryland, United States
Robbins, W.E., Insect Physiology Laboratory Plant Protection Institute, ARS, USDA, Beltsville, 20705, Maryland, United States
Kaplanis, J.N., Insect Physiology Laboratory Plant Protection Institute, ARS, USDA, Beltsville, 20705, Maryland, United States

Analysis of the sterols of the milkweed bug, Oncopeltus fasciatus (Dallas) and dietary sunflowerseeds revealed that there is little, if any, conversion of dietary C28 or C29 phytosterols to cholesterol in this phytophagous insect. The dietary sterols are apparently utilized with little alteration both during development to the adult stage and egg production, and cholesterol comprises <1% of the sterols in either adult males and females or in the eggs. The significance of these findings are discussed in light of the recent discovery that the C28-ecdysone, makisterone A, is the predominant molting hormone in the enbryonated egg of the milkweed bug. © 1977 American Oil Chemists' Society.