[The vitamin requirements of normal and aposymbiotic lasioderma serricorne F. (Coleoptera, Anobiidae) and the role of symbiotic fungi as vitamin sources for their hosts].

Normal Lasioderma serricorne were reared on a totally synthetic, vitamin-free diet for 4 subsequent generations, though development was substantially retarded when compared with that in a diet containing all B-vitamins and a sterol necessary for growth of aposymbiotic larvae. Comparing growth in the presence or absence of the symbionts on diets with a single vitamin omitted it was demonstrated that the microorganisms are able to supply thiamin, lactoflavin, pyridoxine, nicotinic acid, pantothenic acid, choline and a sterol. The importance of symbionts for the production of biotin was shown with aposymbiotic larvae whose parents had been reared on a biotin-free diet, and part of whom had been reinfected with their symbionts. Normal larvae need a concentration of 2 mgs, aposymbiotic of 8 mgs, of choline chloride per g diet for optimal growth. Mesoinositol, carnitine, ribo- and desoxyribonucleic acid did not influence growth on a complete diet. Heliosan beer yeast (Cenovis) contains a growth promoting factor remaining in the insoluble residue after extraction with water, methanol and chloroform.