Studies On The Dynamics Of Arthropod Communities In Tea Field

This thesis came from the project "National Natural Science Foundation" (30871444)—integrated pest management and application for the non-environment damage tea", strived to discover the traits of arthropod community in Capsicum annuum field and enrich the theoretical foundation for IPM of pests.(1) The arthropod total community was divided into tree sub-communities:phytophage, predacious, parasitic and neutrality community as to species'nutrition and predator-prey relationship. Components of the total and sub-communities were analyzed by number of groups, individual numbers and some other ecological indexes. In 2008, arthropods got 43 species which belonged to 38 families, phytophage was prominent part, its relative abundance was 0.6337, dominant species was Empoasca vitis and Pseudaonidia duplex; and that of predacious sub-community was 0.2839, dominant species was Thripidae and Bemisia tabaci. Dominant concentration and dominance in 2008 were compared and the result was predacious sub-community>predacious sub-community>total community, and result of the diversities indexes predacious sub-community>predacious sub-community>total community.(2) Caused by interaction of pest,natural enemy and climate factors, indexes of every communities fluctuated. Change tendency of diversity index in 2008 in total community was:low-high-low-high,while predacious sub-community kept in a high level all the time.(3) The relations between diversity indexes and other ecological indexes in every communities were analyzed by Palb analysis in two seasons. Species numbers had close relationship with diversity indexes in total community; richness,evenness,dominant concentration,dominance all influenced diversity indexes; Species numbers had close relationship with diversity indexes in phytophage sub-community in 2008.(4) Total community and phytophage, predacious community in 2008 were analyzed by clustering. The result in 2008:The total community was divided into 4 clusters when D is 1.81; the phytophage community was divided into 5 clusters when D is 1.52;the predacious was divided into 4 clusters when D is 1.51.(5) The characteristic parameters of arthropod community and its phytophagous,predacious sub-community in Capsicum annuum field in 2008 were analyzed with the method of principal component analysis. The results showed that in 2008:in the three principal component, the contribution of total community and predacious sub-community in tea field was 95.46%,95.04% respectively, in the second principal component, the contribution of predacious sub-community was 92.88%. For the three kinds of communities, the absolute values of normalized regressive coefficient of individual numbers N,species numbers S and richness R were larger, indicating that individual numbers N,species numbers S and richness R had greater contribution.(6)Systematical investigation on populations dynamics of three pests and their natural enemies were conducted in growth. The relationship grade of various natural enemies to ideal dominant natural enemies was analyzed with the grey system theory and method. The results The synthetic ranking result indicated that the orders of main natural enemies of three pests were:Empoasca vitis:Theridion octomaculatum, Tetragnatha maxillosa Xysticus ephippiatus; Toxoptera aurantii:Propylaea japonica, Harmonia axyridis, Mantis religiosa; Pealius akebiae:Neoscona theis, Chrysopa septempunctata, Harmonia axyridis. Gathering averages of Empoasca vitis and Pealius akebiae of major three pests were greater than two due to the aggregation nature of the insect,while those of Toxoptera aurantii was less than two due to the certain environmental factors.(7) Between different insect communities in the year t-test results:Empoasca vitis of two years was significant difference; Brevipalpus theae was more significant difference. Clubiona japonicola,Theridion octomaculatum and Neoscona theisi of two years was no significant difference.(8) Between three different varieties of the insect community analysis of variance,The result of longjing 43,baihaozao and longjing changye of number of species were:longjing 43 and longjing changye was more significant difference;baihaozao and longjing changye was also more significant difference,while longjing 43 and baihaozao was no significant difference in spring. The result of longjing 43,baihaozao and longjing changye of number of individuals were:longjing 43 and baihaozao was more significant difference,longjing 43 and longjing changye was also more significant difference,while baihaozao and longjng changye was no significant difference. The result of longjing 43,baihaozao and longjing changye of number of species and the number of individuals were no significant difference in autumm.