The Study On The Laboratory Population Life Table And Adult Storage Condition Of Scleroderma Sichuanensis Xiao (Hymenoptera: Bethylidae)

Scleroderma sichuanensis Xiao,a new kind of ectoparasitiod wasp which was found in 1994,is a parasitoid of many borers,especially larvae and pupae of long-horned beetles.There are a few S.sichuanensis and they distribute in a narrow rang in nature.They need to be bred in a large scale indoors before being released to the nature to control the pest.So, it's very important to make basic and applied researches on this parasitoid. In this paper,using the Tenebrio molitor L.as the host,life table of laboratory population and adult storage condition of Scleroderma sichuanensis Xiao were studied.The main results are as follows:(1) Parasitization capacity,fecundity and survivorship of S. sichuanensis were observed at 25℃and 75%RH when they developed on the pupae of Tenebrio molitor L..The results showed that the parasitization capacity of S.sichuanensis was good,the average parasitization rate to host was 91.67%by first parasitized it;after shifting the S.sichuanensis to different hosts for 1,2,3 and 4 times,the parasitization rates were 91.30%,94.92%,84.62%and 78.13%, respectively;84%of theâ… part of S.sichuanensis could parasitized 1 time after shifting on different hosts and 33.33%could parasitized 4 times; the average number of eggs layed per female on one host was 71.23,and were 191.73 on several hosts;the survival rate of egg,larvae,and pupae were 93.82%,56.73%,67.36%,respectively.The trend index of the population was 24.48.(2) Life table of laboratory population of the S.sichuanensis at four constant temperatures from 22℃to 31℃were constructed.The results showed that the parasitizating capacity of S.sichuanensis were high at the four different temperatures,and the parasitizating rates were all above 96%.The difference of the effect to the female's fecundity among the four temperatures were not very significantly,the number of eggs laid per female were all above 55,and the maximum number of eggs laid per female was 57.78 at 28℃,while the least was 53.53 at 31℃.The developmental rate increased with the temperature increasing from 22℃to 31℃.The longest duration of the generation was 39.80 days observed at 22℃,the shortest was 18.78 days at 31℃,and in between 27.85 days and 21.15 days at 25℃and 28℃respectively.The threshold temperatures and the effective accumulated temperatures required for egg,larva,pupa and whole generation were 11.74℃,13.30℃,15.33℃,14.41℃and 55.77,84.85,161.89,298.87 degree-day respectively.Relationship between generation survival rate(S),population trend index(I) and temperature(t) could be described by the following expressions: S=-0.5031t²+22.8043t-191.2090(r=0.9982),I=-0.3341t²+15.7747t -152.0486(r=0.9929).(3) The effects of three factors,eclosion days(x₁),processing time for transition(x₂) and storage temperature(x₃) to the survival rate of S. sichuanensis were studied by means of three-factor-five-level quadratic orthogonal regressive rotation combination design.And the results showed that eclosion days(x₁) and storage temperature(x₃) were the major factors affecting the survival rate.Through the model optimization,the optimum storage schemes for surviving above 80%was obtained as follows,eclosion days were 11.5358-12.0204 days, processing time for transition were 1.7740-2.2260 days and storage temperature was 8.2261-8.7739℃.