Isoprenoids from metathoracic scent gland of cotton seed bug, Oxycarenus hyalinipennis (Costa) (Heteroptera: Lygaeidae)

This paper gives the results of a gas chromatographic-mass spectrometric investigation on the composition of the scent oils from the metathoracic scent gland ofOxycarenus hyalinipennis (Costa). It reports the presence of at least 18 different compounds in the scent oils: fatty aliphatic materials comprising the C6 and C8 alk-2-enals, 4-oxo-alk-2-enals, and alk-2-enyl acetates; monoterpenoids comprising α-pinene, limonene, and 1,8-cineole (eucalyptol); and several sequiterpenoids. Observations made during gland reservoir filling indicate that the secretion from the gland tubules undergoes a dramatic change in composition within the first day or so after adult emergence. The newly formed secretion is dominated by fatty aliphatic materials while that formed later is dominated by the isoprenoids. When fully distended with secretion, the lateral scent reservoir contains isoprenoids and little else. It is an interesting feature of the metathoracic system inOxycarenus that oct-2-enyl acetate persists together with oct-2-enal as a major component in the scent oil in the median reservoir. An assessment of the possible biological significance of the chemical findings is attempted.