| Bemisia tabaci (Gennadius) B biotype is a worldwide invasive pest, and it is predomination in competing with some herbivores. We found that there was disadvantage influence of tobacco damaged by B. tabaci on development and fecundity of M.persicae, but no influence on B. tabaci itself. On that basis, we studied the effect of tobacco's defense response induced by B. tabaci on feeding behavior of M. persicae and B. tabaci itself. We also investigated the changes of composition and relative contents of the volatiles from tobacco previously infested by B. tabaci. The purpose of this research is to declare the difference of feeding behavior between M.persicae and B.tabaci, and the role of tabaci in competitive replacement of B.tabaci to M.persicae. Major results are as follows:1. Tobacco infested by B. tabaci had significant disadvantage influence on probing wound, secreting honeydew of M. persicae, however, it had no negative effect on B. tabaci. Compared with leaves of the same position on control plant, on the systemic white-vein leaves damaged by B. tabaci, probing wound number of M. persicae significantly increase 35.55% after feeding 8h. The longer the feeding time, the inhibition to honeydew secreted by M. persicae feeding on the preinfested tobacco plants was more significantly. Compared with the control, the number of honeydew secreted by M. persicae on systemic white-vein leaves damaged by B. tabaci, decreased 72.38%, and the area of honeydew decreased 72.69% after feeding 72h. However, there was no nagtive influence on local leaves damaged by B. tabaci.2. We studied the effect of tobacco's defense response induced by B. tabaci on feeding behavior of M.persicae through EPG technology. The results demonstrated that there was disadvantage influence of systemic white-vein leaves damaged by B. tabaci on feeding behavior of M. persicae. Meanwhile, there was positive effect of local leaves damaged by B. tabaci on it. The results demonstrated that total number of probes, time from start of recording to first E1, time from start of recording to first sustained phloem ingestion, and time between first E1 and sE2 had significantly difference between systemic white-vein leaves damaged by B. tabaci and control after feeding by M.persicae. Through analysis of EPG data, we find that the resistant factors of systemic white-vein leaves damaged by B.tabaci were in mesophyll/epidermis, and phloem tissue. 3. EPG results revealed that, compared with the control, there was no significant influence of systemic white-vein leaves damaged by B. tabaci on feeding behavior of itself, while it had slight positive effect on B. tabaci of local leaves. The results demonstrated that, on the systemic white-vein leaves damaged by B. tabaci, time duration of first probe and time duration of first E1 of B. tabaci had significantly shorten compared with controls. However, there were no significant differences in total duration of probing, total duration of E1 between systemic white-vein leaves damaged by B. tabaci and controls. All results revealed that there ware influence of inhibition on start of probing and phloem of B. tabaci, with the time of prolong, this influence disappear.4. The changes of the volatile from leaves damaged by B. tabaci were studied through SPME and GC-MS technology. The results showed that 34 kinds of new volatile components were found and 29 kinds of volatile components disappeared in local leaves compared with the control, while 25 kinds of new volatile components were found and 28 kinds of volatile components disappeared in systemic white-vein leaves compared with the control. Simultaneously, the ratio of some certain volatile changed in systemic white-vein leaves and local leaves. The result above suggested that the changes of volatile components and relative contents in tobacco leaves damaged by B. tabaci affected the host choice of M.persicae. |
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