The Amino Acid Requirements of the Confused Flour Beetle, Tribolium Confusum, Duval

The larvae of the flour beetle Tribolium confusum have been successfully grown on diets which contain 19 amino acids or the 10 amino acids which are essential in the nutrition of the rat. The larvae of two other beetles, Tenebrio molitor and Dermestes vulpinus, failed to grow on similar diets.2. Tribolium requires the following amino acids for growth: arginine, histidine, lysine, tryptophane, phenylalanine, methionine, threonine, leucine, isoleucine and valine.3. On a mixture of 19 amino acids, which in addition to the above-named acids also contains glycine, alanine, proline, hydroxyproline, glutamic acid, aspartic acid, serine, cystine and tyrosine, growth is somewhat faster than in the presence of 10 amino acids.4. Addition of any one of the non-essential acids to the mixture of the 10 essential ones has no marked effect. None of the amino acids exerted toxic effects when added to the diet in double amounts.5. Tribolium utilizes fully or partly the D-form of methionine, phenylalanine and, possibly, lysine. The D-forms of the 7 remaining essential acids were entirely inactive, but did not show marked toxic effects.