Nutritive Requirements of the Small-Eyed Flour Beetle, Palorus ratzeburgi Wissman (Tenebrionidae, Coleoptera)

Abstract

An artificial diet of casein, glucose, cholesterol, salts and a source of vitamins permitted satisfactory growth and development of the small-eyed flour beetle. Palorus required a sterol and a large quantity of carbohydrate but only a small amt. of protein. Using this artificial diet, the essential vitamins for this insect were found to be thiamine, riboflavin, nicotinic acid, pyridoxine, pantothenic acid, choline and vit. BT [carnitine]. Biotin, folic acid and inositol were apparently not required. Vitamin requirements differ somewhat among such closely related spp. as Palorus, Tenebrio molitor and Tribolium confusum. The effect of a Bt deficiency in Palorus closely resembled that in Tenebrio. A severe larval mortality occurred in the absence of BT. Minimal dosages of a particular Bt concentrate for optimal larval survival were 0.75 [mu]g-/g- of diet for Palorus and between 0.75 and 1.5 [mu]g./g. of diet for Tenebrio. When the amount of choline in the diet was increased up to 1000 [mu]g-/g- of diet, there was a corresponding increase in larval growth and number of pupae formed, and a decrease in time required for pupation.