The sterol requirements of several insects

Abstract

The sterol requirements of 6 insect larvae which normally feed on whole meal flour were investigated (Tribolium confusum, Lasioderma serricorne, Sitodrepa panicea, Silvanus suri-namensis, Ptinus tectus, Ephestia kuehniella). The sterol-deficient basal diet consisted of wholemeal flour, extracted with chloroform (Soxhlet) for 10 hrs. On extracted flour little or no growth took place; addition of various sterols restored the nutritional qualities. This effect was used as a means of comparing the nutritional values of sterols and sterol derivatives. Of positive value were cholesterol, sitosterol, ergostcrol, 7-dehydrocholesterol and cholesteryl-acetate, and, to a lesser degree, cholestanol. Calciferol, [DELTA]5-cholestene, zymosterol, 7-hydroxycholesterol, 7-hydroxy-cholesteryl dibenzoate, 7-dehydrocholesteryl monobenzoate and 7-ketocholesteryl acetate were of no nutritional value. Sitodrepa, Ptinus and Ephestia required larger quantities of sterols than Tribolium, Lasioderma and Silvanus.