Studies On The Dynamics Of Arthropod Communities In Middle Paddy Field

This project were parts of Major State Basic Research Development Program(2010CB126206). Investigated and analyzed systematically by basin-beat method, sweepnet method, yellow basin method and yellow board method, strived to clear theplanthoppers’ regularity of outbreak and their dominant natural enemies in non-controlpaddy field and control paddy field.The thesis investigated systematically the planthoppers and their natural enemies in paddyfield of Huaining country by some mathematical analysis means such as communityanalysis, gray system analysis and ecological niche analysis.1. Sogatella furcifera (Horvath) had superior numbers on July20by basin-beat method,about79.05%of the total planthoppers, while Nilaparvata lugens (St l) had superiornumbers with94.39%on September23. Compared with4(2) by basin-beat method,Nilaparvata lugens (St l) of6(4) had increased127times, Sogatella furcifera (Horvath)had reduced0.17times, and Laodelphax striatellus (Fallen) had reduced0.95times. TheNilaparvata lugens (St l) brachypterous adult were respectively73.33%and12.44%of theadult on August22and September23, showed that5(3) were the main hazards,6(4) werethe emigration onAugust22.2. The species and individuals were most by basin-beat method. In non-control field thenumbers were5196belonging to47species, and in control field there were2426belonging to48species. The next by sweep net method. In non-control field the numberswere6149belonging to47species, and in control field there were1220belonging to38species. The difference of individuals was not significant between basin-beat method andsweep net method, and the difference was significant between these two methods and theother two.3. The results of a paired t-testing between non-control field and control field by sweep netmethod showed that the t values of phytophagous numbers was2.5022, the difference wassignificant. The difference was almostly significant by basin-beat method, while thedifference was not significant by the other two methods.4. The difference of predators and neutralities species and numbers were not significantby the four methods.5.The diversity and evenness in non-control field were lower than in control field bybasin-beat method and sweep net method. It mainly because that the number of planthoppers was large in non-control field which no prevented.6. On two peak days August22and September23, the regulatory function damage indexby sweep net method and basin-beat method are negative, it because that the number ofplanthoppers was large in non-control field.7. In non-control field, the orders of main natural enemies of Sogatella furcifera (Horvath),Laodelphax striatellus (Fallen) and Nilaparvata lugens (St l) were, respectively, Plexippussetipet (Karsch), Erigonidiun graminicolum (Sundevall) and Tetragnatha maxillosa(Thoren); Theridion octomaculatum (Boes et str.), Neoscona theisi (Walckenaer) andTetragnatha maxillosa (Thoren); Marpissa magister (Karsch), Singa pygmaea (Sundevall)and Cyrtorhinus lividipennis (Reuter).8. In control field, the orders of main natural enemies of Sogatella furcifera (Horvath),Laodelphax striatellus (Fallen) and Nilaparvata lugens (St l) were, respectively, Plexippussetipet (Karsch), Erigonidiun graminicolum (Sundevall) and Tetragnatha maxillosa(Thoren); Pirata subpiraticus (Boes et Str), Singa pygmaea (Sundevall) and Erigonidiungraminicolum (Sundevall); Cyrtorhinus lividipennis (Reuter), Pirata subpiraticus (Boes etStr) and Singa pygmaea (Sundevall).