Defensive secretion: biosynthesis of hydrogen cyanide and benzaldehyde from phenylalanine by a millipede

The polydesmid millipede, Oxidus gracilis, is able to convert dietary phenylalanine into benzaldehyde and hydrogen cyanide, components of its defensive secretion. This was shown in tracer experiments employing specifically labeled 14C-phenylalanine. It is presumed that mandelonitrile is a precursor of HCN and benzaldehyde as has been demonstrated in plants.