Species-specific chemical compositions of defense secretions from Parafontaria tonominea Attems and Riukiaria semicircularis semicircularis Takakuwa(Polydesmida: Xystodesmidae).

Abstract

Chemical analyses were conducted on defense secretions from two species of millipedes, Parafontaria tonominea and Riukiaria semicircularis semicircularis (Polydesmida: Xystodesmidae). Hydrogen cyanide was detected in both species using test papers impregnated with picric acid, while the foul odor of these millipedes changed to that of benzaldehyde. n-Hexane extracts of the two species indicated different profiles of gas liquid chromatograms. Benzaldehyde and mandelonitrile were detected as the common components in both species, while benzoyl cyanide and mandelonitrile benzoate were limited to P. tonominea. These results indicate a difference in the chemical composition of the defense secretion between the two species. The high performance liquid chromatograms of methanolic extracts from the two species looked similar, consisting only of mandelonitrile as the major and benzaldehyde as the minor components. On the other hand, benzoyl cyanide and mandelonitrile were not detectable in the methanolic extracts from P. tonominea despite their high solubility to methanol, indicating that, for some reason, the two cyanogenetics are not secreted during methanolic extraction.