Developmental Performances Of Nesidiocoris Tenuis And Its Predation Of Prodeni A Litura And Bemisia Tabaci On Tobacco And Tomato Plants

Nesidiocoris tenuis(Hemiptera:Miridae)is a zoophytophagous mirid bug,mainly carnivorous but herbivorous.It is of important economic and ecological significance in integrative pest management in agricultural crop field.Plant and prey identity will certainly have an impact on its growth and predation.To reveal this impact,the growth and predation of Nesidiocoris tenuisis were studied with two different plants,tobacco and tomato,and two prey,Spodoptera litura young larvae and Bemisia tabaci.The main results and conclusion obtained from this thesis study are summarized as followed.1.Effects of S.litura larvae on developmental performances of N.tenuisNon-choice trials was made in laboratory to investigate the role of the prey S.litura larvae(available or not)and plants(tomato or tobacco)as the food in nymphal developmental performances of N.tenuis.The results show that,without feeding S.litura larvae,N.tenuis nymphs developed only to the 3rd(on tomato leaves)or 4th stadium(on tobacco leaves);but when feeding the larvae,N.tenuis nymphs developed successfully to adult emergence.When S.litura larvae were available,two food plants did not differ in affecting N.tenuis nymphal development time,survival rate,adult emergence rate and female proportion,but did in affecting adult body weight with adults fed tobacco larger than those fed tomato leaves.2.Predation on S.litura larvae and B.tabaci on tobacco and tomato plantsTrials were made to assess the functional responses of female adults to different densities of S.litura larvae on potted tomato or tobacco plants,using Holling II random model to fit functional responses and the non-linear least square method to estimate behavioral parameters.The predation of N.tenuis on S.litura larvae and B.tabaci in tobacco and tomato is in accordance with Holling ? model.The mutual regulation exists between predators,pests and plant.At the same prey density,the predation of N.tenuison on tobacco is larger than that on tomato,and on the same plant,the predation of N.tenuis to S.litura larvae is larger than that to B.tabaci.By direct observations on treatment time of functional reaction,this paper quantitatively manifested that handling time is inversely related to prey density,which fixing the handling time in functional reaction model,and describing the predation of N.tenuis more accurately.3.Interference effect on tobacco and tomato plantsTrials were made to assess the interference effect of female adults of N.tenuis on S.litura larvae and B.tabaci on tobacco and tomato potted tobacco or tomato plants,using the model E = Q P-m to estimate the mutual interference constant and quest constant.The results showed that,with the increase of density of N.tenuis,the predation to S.litura larvae and B.tabaci feeding volume decreased.The mutual interference constant of N.tenuis on B.tabaci on tobacco or tomato plant was larger than that on and tomato plants.The mutual interference constant of N.tenuis on S.litura larvae or B.tabaci on tobacco plant were larger than that on tomato plants.