Abstract
An amino acid analysis of the acid hydrolyzates of the pupal sheaths of Bombyx, Drosophila and Musca was performed with a Hitachi KLA-2 type amino acid analyzer. β-alanine was demonstrated in the pupal sheath of wild strains (pupal color being brown) of these insects, but not in the pupal sheaths of some black pupa strains. However, in the bp black pupa mutant of a silkworm, β-alanine was detected in the pupal sheath. This mutant bp is quite different from the “sooty” black pupa mutant in which no β-alanine is contained in the pupal sheath. In the pupal sheath of a hybrid (bp/+) of Musca domestica, whose pupal color was indistinguishable from that of a wild one, β-alanine was detected as much as in that of a wild type (+/+). In the pupal sheath of a hybrid (so/+) of Bombyx mori, β-alanine was also detected.
