The characteristic smell emitted from two scale insects, Ceroplastes japonicus and Ceroplastes rubens

Abstract

Abstract The volatile components emitted from two scale insects, Ceroplastes japonicus and Ceroplastes rubens, were identified using GC–MS analysis. The major volatile components of the solvent extract from C. japonicus were α-humulene (35.8%) and δ-cadinene (17.0%), while those of C. rubens were β-selinene (10.3%) and β-elemene (5.1%). In GC/olfactometry, linalool, butyric acid, 3-methylbutyric acid, 2-methylbutyric acid, and vanillin were identified as the odor-active components of the extract from C. japonicus, in addition to trace amounts of trans-4,5-epoxy-(2E)-decenal, 4-methyl-(3E)-hexenoic acid, and phenylacetic acid. With regard to C. rubens, trans-4,5-epoxy-(2E)-decenal, 3-methylbutyric acid, and phenylacetic acid were identified as the odor-active components. Besides, decan-1,4-olide (γ-decalactone) with milky cherry-like note and 3-hydroxy-4,5-dimethylfuran-2(5H)-one (sotolone) with brown sugar-like note were also detected as the characteristic cherry-like sweet-and-sour note of these two scale insects. Abbreviations GC: Gas chromatography; GC/O: gas chromatography/olfactometry