The Nutrition of the Mealworm, Tenebrio molitor L. (Tenebrionidae, Coleoptera)

Abstract

Details are given about the composition of artificial diets for T. molitor, and the methods of testing for nutritional deficiencies. The rate of growth of Tenebrio very much depends on the water content of the food, growth being fastest on food in equilibrium with 70% R.H., very slow at 30% R.H., and hardly proceeding at 13% R.H. Tenebrio requires a high percentage[long dash]80 to 85%[long dash]of carbohydrate in the diet. The effects of glucose and starch are similar. Data are given on growth in the presence of different proteins. Casein, lactalbumin and peanut protein seem to give optimal effects; soybean protein becomes satisfactory only after extensive heating, while zein, gliadin and enzymatic hydrolysates from casein or lactalbumin are of only slight value. Cholestrol is a necessary ingredient of the diet. There is no indication that fat is required. Wholewheat flour is of only slight nutritional value but becomes an optimal food with the addition of 5% yeast. The deficiency is principally due to a lack in riboflavin. Tenebrio requires the following vitamins of the B-complex, minimal optimal amounts being expressed as [mu]g./g. of the dry diet: thiamin (1), riboflavin (2-8), nicotinic acid (16), pyridoin (2), pantothenic acid (8), biotin (0.16), pteroylglutamic acid (0.12) and choline (300). In the absence of choline, growth is somewhat depressed. Tenebrio also requires a yet undetermined factor Bt. No growth whatsoever takes place in the absence of thiamin, riboflavin, nicotinic acid, pyridoxin or pantothenic acid; very slow growth is possible without biotin or pteroylglutamic acid, but growth is little affected without choline; there is no indication that inositol or p-amino-benzoic acid are required. In the absence of riboflavin or pantothenic acid the larvae die much sooner than in cases of deficiencies of the other B-vitamins.