Linoleic acid, vitamin E and other fat-soluble substances in the nutrition of certain insects, Ephestia kuehniella, E. elutella, E. cautella and Plodia interpunctella (Lep.).

In a previous publication (Fraenkel & Blewett, 1943) it has been shown that a number of insects which normally live on wholemeal flour or other cereal products grow badly or not at all on flour thoroughly extracted with chloroform unless a sterol, e.g. cholesterol, is added to the diet. For several beetle larvae the diet becomes optimal upon addition of a pure sterol, but for the caterpillars of a moth, Ephestia kuehmella, wheat-germ oil has a much better effect than a sterol. Using artificial diets, consisting of glucose, casein, yeast and cholesterol, it was found that E. kuehmella grew well in the presence of wheat-germ oil and badly without it. Subsequently it emerged (Fraenkel & Blewett, 19466) that the closely related species E. elutella grew fairly well on similar diets in the absence of wheat-germ oil and pupated normally, but the adults invariably failed to emerge from the pupae. With wheat-germ oil, growth was fast and emergence normal. Analysis of the factors in wheat-germ oil which are required by the moths of the genus Ephestia is the subject of the present paper. Some of the results have already been shortly reported (Fraenkel & Blewett,