Regulation Of Herbivore-Induced Rice Volatiles On Interspecific Interaction Of Nilaparvata Lugens And Chilo Suppressalis

In their natural environment plants interact with complex insect communities consisting of numerous species and different trophic levels.Herbivore-induced plant volatiles(HIPVs)play key roles in these complex interactions.Such as regulating the feeding and oviposition of insects and avoiding natural enemies and so on.Here we studied this for the brown planthopper(BPH)Nilaparvata lugens(St?l).We had found that BPH exhibits a strong preference to rice plants(Oryza sativa)that are already infested by the rice striped stem borer(SSB),Chilo suppressalis(Walker).Whether Chilo suppressalis females prefers to oviposite on BPH-infested rice or co-infested rice.Whether herbivore-induced rice volatiles mediated interspecific interaction of Nilaparvata lugens and Chilo suppressalis.Those problems were unclear.In order to explain those problems,in this paper,rice,Chilo suppressalis and Nilaparvata lugens were taken as research objects.We completed series ecological and biochemical experiments in this study.It clarified that herbivore-induced plant volatiles play an important role in the host selection of BPH and SSB.The mainly results as following:(1)Based on identified SSB-infested rice volatiles in the laboratory,we selected 15 compounds that may regulate the behavior of brown planthopper.The H-tube olfactomerer studies revealed that namely α-pinene,β-caryophyllene,2-nonanone,germacrene D and DMNT had a strong attraction effects on the BPH compared to the control.In contrast,four compounds,methyl sylicylate,2-undecanone,2-tridecanone,TMTT,significantly repelled the BPH compared to the control.There was no effect on the BPH behavior for the six remain compounds,(E)-2-heptenyl acetate,tridecanal,benzyl benzoate,isophorone,2-pentadecanone,o-cymene and isopropyl myristate.(2)The oviposition experiment in the greenhouse was used to studied the oviposition preference of Chilo suppressalis females to BPH-infested rice plants or co-infested rice plants.The results showed that Chilo suppressalis females were attracted by BPH-infested plants and co-infested plants when compared with uninfected plants,but Chilo suppressalis females were repelled by SSB-infested plants;Chilo suppressalis females were attracted by BPH-infested plants and co-infested plants when compared with SSB-infested plants;Chilo suppressalis females had no oviposition preference for BPH-infested plants or co-infested plants.(3)We collected nocturnal volatiles of BPH / SSB-infested rice plants and co-infested rice plants,aimed to reveal whether the preference of the rice stem borer adults for spawning of different treated rice plants from the difference in the spectrum of rice volatiles.A total of 48 compounds were detected in the headspace of uninfested rice plants;whereas 52 compounds were detected for rice plants damaged by BPH;the number of detected volatile compounds increased to 61 when the rice plants were infested by SSB only,or by both SSB and BPH.A projection to partial least squares-discriminant analysis(PLS-DA)using the contents of all detected volatiles showed a clear separation between different treatments plants.In summary,herbivore-induced plant volatiles play an important role in the host selection of BPH and SSB.Studies have identified key volatiles of SSB-infested rice plants that affect the behavior of the brown planthopper.Meanwhile,it is also definite that the different volatiles of rice infested by different pests lead to different selections of Chilo suppressalis females.However the function of specific compounds remains to be further studied.This result provides significant basis for the preparation of repellents or attractants for controlling the brown planthoppers.and analyze the rice mediared interspecific relationship between BPH and SSB.