| This thesis come from the project "high quality megranate high yield planting"of Anhui Agriculture Synthesis Office. Strive to discover the traits of arthropod community in megranate field and enrich the theoretical foundation for IPM of pests.(1) The arthropod total community was divided into two sub-communities: natural enemies sub-community and pests-neutral insects sub-community as to predator-prey relationship. Components of the communities were analyzed by number of groups, individual numbers and some other ecological indexes and so on. Arthropods got belonged to 55 species of 47 families, the pests-neutral insects sub-community was prominent to total community, its relative abundance was 0.8948 and that of natural enemies sub-community was 0.1055. Dominant concentration, dominance and the diversities indexes of every communities were compared and the result was dominant concentration and dominance: pests-neutral insects sub-community >total community >natural enemies community; diversity index was on the other way round: natural enemies community>total community>pests-neutral insects sub-community.(2) Caused by predator-prey interaction and climate factor, indexes of every communities fluctuated from time to time. Diversity indexes in total community and pests-neutral insects sub-community changed from loosely to highly tended, to loosely and then to highly tended again. And that of natural enemies sub-community kept in a high level all the time. That indicated the natural enemies sub-community was stable.(3) The relations between diversity indexes and other ecological indexes in every communities were analyzed by Palb analysis. Diversity index in total community and pests-neutral insects sub-community was decided by evenness, richness, dominant concentration prominently and that of natural enemies sub-community was decided by dominant concentration prominently.(4) Analyzed the 8 investigation results of every communities by fuzzy clustering. The results of total community and natural enemies sub-community were divided into 4 clusters and that of pests-neutral insects sub-community were divided into 3 clusters. The clustering reflected the different condition of communities in different time.(5) Systematical investigations on populations dynamics of Aphis gossypii and its natural enemies in all stages of megranate growth were conducted. The relationship between population of natural enemies and Aphis gossypii population size was analyzed with the grey system theory and method, and the relational grade of various natural enemies to ideal dominant natural enemies was also analyzed. The results indicated that Erigonidium graminicola, C.sinica were the major natural enemies affecting Aphis gossypii, followed by Tetragnathidae, Chrysopa septempunctata and Therdion octomaculatum.(6) The temporal and vertical niche breadth and overlap of Aphis gossypii and its natural enemies were analyzed. The temporal and vertical breadth of Aphis gossypii were all broad. This indicated that the Aphis gossypii appeared in all stages of megranate growth and al horizontal directions. The Erigonidium graminicola, Chrysopa septempunctata, Tetragnathidae and Tromobidiidae had high overlap grad with Aphis gossypii were its main natural enemies.(7)Investigations on the spatial construction and distribution of Aphis gossypii and Erigonidium graminicola at different period from 2002.4 to 2002.11. The results indicated that the semivariogram of them could be described by spherical model. This meant theamount and spatial distribution ofErigonidium graminicola was closely related to that of Aphis gossypii.(8) The use of pesticide "KKY" had a influence on the condition of communities. Dominant concentration of CK and low-thickness area changed from highly to loosely tended, to highly tended again and the high-thickness had the opposite trend. The CK and low-thickness area had a higher level of diversity index than high-thickness. |
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