Mechanism Of Herbivore-induced Artemisia Ordosica Volatiles In Host Plant Selection Of Insect Pests

Artemisia ordosica (Asteraceae) is one of the most important plants for desertification control in arid and semi-arid regions of Northwest China. Three major stem-boring herbivores of it are Adosopiits sp.(Coleoptera:Curculionidae), Sphenoptera sp.(Coleoptera:Buprestidae) and Holcocerus artemisiae (Lepidoptera:Cossidae). For understanding the reaction mechanism of herbivore-induced A. ordosica volatiles in host plant selection of three herbivores, we took healthy, mechanically damaged A. ordosica, and plants infested with larvae of the herbivores as reasearch objects, useing a dynamic headspace method, electroantennogram and "Y" tube, the reaction mechanism of A. ordosica volatiles in host plant selection of three herbivores was studied systematically. Main conclusions are as follows:①Twenty-eight major compounds were identified, and qualitative as well as quantitative differences were compared. The green leaf volatiles2-hexenal,(Z)-3-hexen-l-ol,2-hexen-1-ol,1-hexanol and (Z)-3-hexen-l-ol, acetate were present in all of the damaged plants, but in relatively lower proportions when plants infested by herbivores, and the terpenoids a-copaene,β-cedrene, and (E,E)-a-farnesene, and the ester methyl salicylate were present in all herbivore-infested plants.②Two beetles response to these compounds are tested with electroantennogram (EAG). By using the mehod of LSD multiple compared analysis, the result showed five volatile compounds such as a-pinene,2-hexen-l-ol, D-Limonene,β-pinene and camphene elicited strong EAG response by female Sphenoptera sp.. One volatile compound such as a-pinene elicited strong EAG response by male Sphenoptera sp.. Five volatile compounds such as2-hexen-l-ol, methyl salicylate, camphene, a-pinene, and4-carene elicited strong EAG response by female Adosomus sp.. Six volatile compounds such as β-myrcene, ocimene,4-carene,(E,E)-a-farnesene, D-Limonene and β-caryophyllene elicited strong EAG response to male Adosomus sp.③With Y-shape olfactory detector, the results of real samples showed that female Sphenoptera sp. were strongly attracted by the five volatile compounds and male Sphenoptera sp. were strongly attracted by a-Pinene. Female Adosomus sp. were strongly repelled by methyl salicylate and strongly attracted by the four volatile compounds whereas male Adosomus sp. were strongly attracted by the six volatile compounds. The results of real plants showed that both female and male Sphenoptera sp. showed no preference for healthy and Adosopius sp. larvae-infested A. ordosica. Female Adosomus sp. preferred healthy A. ordosica to Sphenoptera sp. larvae-infested ones while female Adosomus sp. showed no preference for two kinds of plants.The paper further derives new theoretical basis of making a thorough study of explicating how Sphenopteni sp., Adosomus sp. and Holcocenis urlemisia make a host selection and aims to enrich the theoretical basis and scientific foundation for IPM of pests by studies of HIPVs. In the meantime, attractants and repellents of plant origin can be exploited for the effective control.