Electrophysiological and behavioural responses of Stegobium paniceum to volatile compounds from Chinese medicinal plant materials

BACKGROUND:Stegobium paniceum(Coleoptera, Anobiidae) is an important pest of stored products causing severe damage todried Chinese medicinal plant materials (CMPMs). Plant volatiles play an important role in host-searching of insects. The olfac-tory responses ofS. paniceumto the most abundant volatile components of some drugstore attractant CMPMs such asPanaxnotoginseng,Angelica sinensis,Gastrodia elataandPeucedanum praeruptorum, namely falcarinol, 3-n-butylphthalide,p-cresoland⊎-pinene, respectively, were studied by electroantennography (EAG) and behavioural bioassays in six- and four-armolfactometers.RESULTS: EAG recordings showed that male and female antennae are able to perceive the test compounds in a wide range ofconcentrations and in a dose-dependent manner. Moreover, for each dose of different compounds tested, no significant differ-ences were found between the mean male and female EAG responses. In six-arm olfactometer bioassays,S. paniceumexhibitedpositive responses to falcarinol, 3-n-butylphthalide,p-cresol and⊎-pinene at doses of 1, 10, 100, 500 and 1000∼g. The mostattractive dose was 500∼g for falcarinol, 100∼g for 3-n-butylphthalide, 500∼g forp-cresol and 1000∼g for⊎-pinene. Olfac-tory preferences ofS. paniceum, based on comparison of these four compounds at their optimally attractive concentrationsin a four-arm olfactometer, were 3-n-butylphthalide>p-cresol>falcarinol>⊎-pinene.CONCLUSION: The results indicated that the four volatiles of CMPMs are perceived by the peripheral olfactory system ofS. paniceumadults and are able to individually elicit a positive chemotaxis inS. paniceumadults confirming the role of chemicalcues in host-plant detection and selection of this pest. Furtherfield studies are needed to evaluate the potential of the attrac-tive compounds identified in this study, particularly 3-n-butylphthalide, to be applied as a novel monitoring and control toolagainst this storage-beetle pest.