The Study On The Rearing Of Harpactor Fuscipes(Fabricius) And Its Predation To Nilaparvata Lugens(St(?)l)

Harpactor fuscipes(Fabrieius)belongs to Reduviidae,Hemutera,which is an important predator in tobacco growing.Basically it was used to control tobacco pests,such as Myzus persicae(Sulzer),Helicoverpa assulta and Spodoptera litura and so on.And it is also founded in paddy field which is tobacco-rice farming.Therefore,this thesis analyze the predation of H.fuscipes to Nilaparvata lugens in paddy field in order to provide scientific basis for ecological control on N.lugens.In this paper,in order to find out the influences on the growth and development of nymphs of H.fuscipes,we reared with three different types of prey,namely N.lugens,S.litura and Tenebrio molitor.And then,functional response model,effect parameters intraspecific mutual interference and density influence were established,so that to illustrate its control capability to N.lugens.Besides,H.fuscipes’ predacious number on N.lugens was measured by treatments in pot experiment,so that the theoretical foundation can be provided to H.fuscipes on the controlling of N.lugens in paddy field.The main conclusions are as follows:The experiments showed that,through rearing with three different types of prey,namely N.lugens,S.litura and T.molitor,1st~5th nymph of H.fuscipes still can all grow and develop normally.However,there are some significant difference s in the biological parameters.The differences were the following: after preying the Nilaparvata lugens,the body length and width of the nymphs of different ages were obviously higher than those of the H.fuscipes’ 3rd instar nymphs and the 4th instar nymphs fed with S.litura and T.molitor,respectively.At the same time,the bod y weight of the 3rd instar nymphs and the 4th instar nymphs(4.92mg;11.15mg)were apparently higher than that of the S.litura.And the survival rate of 1st-5th nymp h were respectively 90.66%,97.14%,98.57%,81.89%,94.29%,in which the survival of the 2nd instar nymphs,the 3rd instar nymphs and the 5th instar nymphs were obviously higher than that of S.litura and T.molitor.And as for the total survival rate,when rearing with N.lugens,the rate was 68%,which was much higher tha n that of S.litura and T.molitor,respectively.In addition,the development duration of each nymph were 7.71 d,6.89 d,8.98 d,10.05 d,16.20 d,and the total development duration was 49.86 d.Hence,the results showed that the rearing effect of H.fuscipes was much better in N.lugens nymph than T.molitor larvae and S.litura larvae.When preying different ages of N.lugens,namely 2nd~3rd nymphs,4th~5th nymphs and brachypterous female adults,Holling II functional responses are also modeled.On condition that with the same prey density,the H.fuscipes in different ages that have the maximum daily number of N.lugens,respectively 207.245,53.665 and 70.566,are all female adults,and the minimum one are all the 3rd instar nymphs(14.986,18.972 and 7.300).then it can be concluded that the adult H.fuscipes has the most powerful predation capability to N.lugens,then next the H.fuscipes’ 5th instar nymphs,and last the 3rd instar nymphs.As the density of N.lugens increases,the search effect estimation of different insects decreases gradually and then becomes stable.The search effect of H.fuscipes 3rd~ 4th instar nymphs to the nymphs of N.lugens was higher than brachypterous female adults.The search effect` trend of H.fuscipes 5th instar nymphs and female adults on the N.lugens female adults was similar.The search effect on the brachypterous female adults was significantly higher than that of the 4th ~5th instar nymphs.The functional response equation of the female adults is as follows: = 30.309-0.611( = 0.983).the interference effect of the population density of the H.fuscipes female adults to its preying activity was as follows: = 0.2598-1.1591( = 0.9803).By potting method outdoors,the results shows that with the increase of prey density,there was no significant difference in the predation between the H.fuscipes’ 5th instar nymphs and the 4th instar nymphs,But both their predation are higher tha n the 3rd instar nymphs and female adults.After the tests for 1d,3d and 7d,there is a significant difference between the different treatments,the H.fuscipes’ 5th instar nymphs have the most powerful predation capability(10.60,21.00,24.80),and the n the 4th instar nymphs(10.00,19.60,22.00),last the 3rd instar nymphs(9.20,11.40,12.60)...