Studies on the Nitrogenous Compounds in Urine of Mature Silkworm Larvae, Bombyx mori (Lepidoptera : Bombycidae)

Abstract

Mature silkworm larvae, Bombyx mori, discharged about 0.3ml of urine² immediately before cocoon spinning. Urine was composed of several kinds of nitrogenous compounds including 16 kinds of amino acids, urea, uric, acid, protein and ammonia. The quantity of each nitrogenous compound in urine varied according to the food condition during the 5th instar and silkworm races. Disc-electrophoretic analysis revealed that several proteins in urine were derived from digestive juice. The role of urine in nitrogen excretion is discussed.