The Ecological Manipulation Mechanism Of Host Selection Of Bemisia Tabaci

Although,insect herbivores are generally thought to select hosts that favor the fitness of their progeny,this “mother-knows-best” hypothesis may be challenged by the presence of a plant virus.Our previous study showed that the whitefly,Bemisia tabaci,the obligate vector for transmitting Tomato yellow leaf curl virus(TYLCV),preferred to settle and oviposit on TYLCV-infected rather than healthy host plant,Datura stramonium.The performances of B.tabaci larvae and adults were indeed improved on virus-infected D.stramonium,which is consistent with “mother-knows-best” hypothesis.But there is little known about the change of whitefly(as a non-vector)selection and performance when Tomato spotted wilt virus(TSWV)-infected host plants.In addition,whitefly can aggregation on host plant.But we poorly understand about this phenomenon.Previous work has shown that feeding by the whitefly can reduce plant resistance and that whiteflies tended to aggregate on infested plants.However,metabolomic changes in the plant and associated whitefly behavioral responses underlying this form of herbivore-induced susceptibility remain poorly understood.To understand the ecological manipulation mechanism of host selection of whitefly,the specific results are as follows:1.The TSWV-infected host plant can attract whitefly but reduced their fitnessIn this study,B.tabaci Q displayed the same preference to settle and oviposit on Tomato spotted wilt virus(TSWV)-infected host plants,D.stramonium and Capsicum annuum,respectively.As a non-vector of TSWV,however,insect performance was impaired since adult body size,longevity,survival,and fecundity were reduced in TSWV infected D.stramonium.2.TSWV infection can modify the plant volatile profiles and induce an odor-mediated behaviorIn this study,Infected plants have reduced quantities of o-xylene and a-pinene,and increased levels of phenol and 2-ethyl-1-hexanol in their headspace.Subsequent behavior experiments showed that o-xylene and a-pinene are repellant,while phenol and 2-ethyl-1-hexanol are attractive.This indicates that the preference of B.tabaci for virus-infected plants is modulated by the dynamic changes in the volatile profiles rather than the subsequent performances on virus-infected plants.3.B.tabaci specifically recognizes and responds to plants attacked by conspecifics,which are superior hostsIn this study,we investigated how B.tabaci infestation affects host physiology and the preference and performance of conspecific feeders.In addition,we identified cues that B.tabaci uses to assess host-plant quality.B.tabaci adults exhibited consistent behavioral preferences for plants that experienced actual and simulated herbivory by conspecifics(consistent with observed effects on whitefly performance),but not for plants that were merely mechanically wounded.Leaf extracts of B.tabaci-infested plants showed altered terpenoid and flavonoid profiles.Manipulative behavioral experiments indicated that suppression of the monoterpenes ?-phellandrene and ?-terpinene and of flavonoids by B.tabaci infestation influenced the foraging and oviposition preferences of conspecifics.This study describes feeding-induced changes in plant physiology that affect whitefly behavior and performance.The results explain why B.tabaci tends to aggregate on plants in the field and suggest the possibility that control of B.tabaci might be enhanced by genetically modifying plants to mimic herbivore-induced changes in terpenoid and flavonoid patterns.