Ecological Studies On Orchard Spider Community

In this article , the composition and niche of spider community in orchard in Taigu of Shanxi was preliminarily analysed . At the same time , the reaction of function that dominant species about spider-Philodromus cespitum who preyed Aphis pomi DeGeer was researched ,these theoretical results were provided for further protecting and using natural enemies and doing sustainable IPM .1 .Spider community in orchard in taigu of shanxi was systemically in investigated in 2002.There were 4447 spiders were gathered in total .After primarily classing and authenticating in lab ,these spiders belonge to 15 families ,48 genuses and 68 species (among them ,a new species of Linythidae was found and a spider which was not ascertained was still being authenticated at present ),applying. berger-parker(1974) index of dominant degree(d) showed that dominant species and dominate species of spider community in orchard in different time.Whereas ,density and trends in fields of dominant species of spider were primary analysed.2. It's preliminarily studied that the degree of richness (S) ,total individual number (N),index of diversity(H) and degree of evenness (E) about the changes of fluctuation ,The degree of richness of species, evenness and total individual number(N) were regarded as independent variables and diversity(H) as dependant variable .Multiple gradual regression analysis were done, the analysis of main compositions of diversity indicated that the main composition of diversity affecting spiders was evenness in young period and medium-term of growth of apple trees. But it was the degree of richness of species in later stage .3. Applying the method of two parameters testing aggregated intensity. Which put by lwao(1968) .namely M*-M ,the method of regression analysis .Compared aggregated intensities of four orientations of four dominant species .Spiders location :east , south, west, north and three layers of apple trees: upside, mediun, undersurface and the earth of surface .M*-M of four dominant spiders classes were all beyond 1 which showed that space distribution of each orientation of four dominant spiders all .Belonged to aggregated distributions (except lycosa whose number was 0 on crown of tree) and according to α and β Individual average congestion of each classes and aggregated guidelines of population per unit were preliminarily researched.4. Eight dominant species of spider in apple tree were quantitatively estimated from the aspect of niche breadth and overlap value by time apace and two-space of two -dimensionalniche. According to two-dimensional niche overlap value and the similar guideline of species mistiness analysis was done,if clustering threshold is λ =0.8353,eight spiders in apple trees were divided into two obvious competing species and two separated species.5. Under the condition of lab,the function that the philodromus cespitum preyed Aphis pomi DeGeer was researthed. Density of quarries and preyers and united reaction recioprocal interference and effects of preying function under different temperature were analysed .Theritical value which was simulated.with Moiling ,Watt.Hassell equations. And observational value were closer and after tested by x2, errors were not obious (