Indication of bioactive candidates among body volatiles of gregarious adult locusts <i>Locusta migratoria manilensis</i> by electroantennography (EAG) test

Abstract

Gregarious adult locusts are believed to release many bioactive volatiles from their bodies for the mediation of their biological characteristics. The determination of these bioactive body volatiles can contribute to the development of new, environmentally benign methods of locust control. An important locust, Locusta migratoria manilensis is an extremely destructive agricultural pest in China. Body volatiles of gregarious L. m. manilensis adults were found to be involved in mediation of aggregation behavior, but bioactive components in the body volatiles had not been indicated. In this study, four compounds were identified from body volatiles of gregarious L. m. manilensis adults using gas chromatography-mass spectrometry analysis: 2-hexanone, butyl acetate and α-pinene from both sexes and 2-heptanone from males only. The electroantennography (EAG) test indicated that gregarious adult males and females had the same EAG response pattern to these compounds. 2-Hexanone, 2-heptanone and butyl acetate elicited dose-dependent responses, which are considered as bioactive candidates among body volatiles. The two ketones, 2-hexanone and 2-heptanone, were the strongest olfactory stimuli for gregarious L. m. manilensis adults. The contribution of these EAG-active compounds to the mediation of aggregation or other behaviors still remains to be further investigated.

Key words: Locusta migratoria manilensis, body volatiles, GC-MS, EAG, bioactive compounds.