Volatiles in the Dorsal Abdominal Glands and Exuviae of Leptocoris abdominalis and Leptocoris augur (Heteroptera: Rhopalidae)

Compounds in the dorsal abdominal glands (DAGs) of adults and nymphs, and exuviae of two scentless plant bugs Leptocoris abdominalis (F.) and Leptocoris augur (F.) (Heteroptera: Rhopalidae), were studied by gas chromatography-mass spectrometry. For both species, two dorsal abdominal glands (median and posterior glands) are found in the nymphs, whereas in adults only the posterior gland is functional and the median gland is reduced. Monoterpenes are the major compounds in posterior glands for both species. For L. abdominalis β-pinene is most abundant monoterpene and for L. augur, limonene is most abundant monoterpene. Alkenals and alkenoic acids were found in median glands of both species. There was no sexual dimorphism in the morphology and the contents of the DAGs of adults. Analysis of the compounds found in the exuvia indicated that components in the median gland were shed with the exuvia. Quantitative analysis of the major monoterpenes and alkenals in the DAGs of different ages of L. abdominalis supported the observation that components in the posterior gland were retained in the insect after each molting. Possible functions of the components in the DAGs are discussed.