Non-consumptive Effect Of Encarsia Formosa On The Growth,Development And Physiology Of Bemisia Tabaci And Its Physiological Mechanism

In addition to the direct consumption relationship such as predation or parasitism between natural enemies and their prey,there is also a non-comsumptive effect.When the prey is perceived to be preyed on or parasitized,its own behavior,growth and development,and physiological and biochemical metabolism will also change.These changes bring a series of effects to the prey its individual,its population,and even the ecosystem.Bemisia Tabaci(Gennadius)is a worldwide pest with wide host range.They pierce and suck plant juice,which leads to plant nutrition loss;The honeydew secreted cause dark mildew;Meanwhile,B.tabaci is also a disseminator of various plant viruses.Encarsia Formosa,dominant parasite to B.tabaci,with high efficiency,strong specificity and environment-friendly parasitism,has become an important natural enemy insect used in the biological control of B.tabaci.During the process of prevention and control,in addition to the direct parasitism leading death to B.tabaci,is it possible that the process of E.formosa searching for host also affects the growth,reproduction,physiology and biochemistry of the B.tabaci? In this paper,B type B.tabaci and E.formosa were selected as research objects,setting non-comsumptive effect on the former,to observe the growth,physiological,biochemical metabolism and reproduction changes under such stress.The main results are as follows: 1.Influence on the growth and reproduction of B,tabaci caused by stress from E.formosa.The life span of B.tabaci adults was significantly shortened after being stressed in different period during the nymph stage,such influence becomes bigger if B.tabaci was stressed at greater age;Secondly,the stress significantly reduced the fecundity of B.tabaci adults;Thirdly,the stress significantly accelerated the developmental duration of B.tabaci offspring,but obviously reduced the survival rate of the offspring.2.Influence on the nutrients in B.tabaci caused by stress from E.formosa.Setting B.tabaci adults under non-comsumptive effect environment,to mensurate the changes of nutrients in B.tabacis.The results shows that protein content was not changed obviously,but the content of glycogen and trehalose was decreased and the fat content increased,which means the stress caused carbohydrates in the body transformed into fat,thus to improve the antireversion force of B.tabaci.3.Influence on B.tabaci's endocrine regulatory gene expression level caused by short time stress from E.formosa.Vg,Vgr,Btjhe,Jhbp,Ecr and E75 are genes related to reproductive regulation in B.tabaci,and are closely related to the regulations of reproduction and life span.After short time stress(30 min,1 h,3 h,6 h,12 h,24 h)from the E.formosa,conduct fluorescence quantification detection to detect the expression level changes of Vg,Vgr,Btjhe,Jhbp,Ecr And E75,and found that these 6 genes were down regulated in different degree.Which showed that short time stress affects B.tabaci's endocrine regulatory gene expression level,and caused stress response to B.tabaci.4.Influence on B.tabaci's heat shock protein gene expression level caused by short stress effect from E.formosa.Hsp70 and Hsp90 are known as heat shock proteins,Hsc70 are known as heat shock protein,they are stress resistant protein produced by the organism under unfavorable environmental conditions.By setting different short time stress to B.tabaci(30 min?1 h?3 h?6 h?12 h?24 h),conduct fluorescence quantification detection to detect the expression level changes of Hsp70?Hsp90?Hsc70,and found that these 3 genes were up regulated in different degree after stress.Which showed that short time stress affects B.tabaci's heat shock protein gene expression level,thus to improve the antireversion force of B.tabaci.In this paper,the research of E.formosa's stress influence to B.tabaci,was based on the expecting to offer some reference to sustainable green prevention and control of B.tabaci;Further discuss the cost of B.tabaci to avoid natural enemies,and improve understanding on the influence of natural enemies to the individual and population of prey,thus to provide one more theoretical basis for the application of biological control of pests.