Studies On The Dynamics Of Arthropod Communities In Vigna Unguiculata W.ssp. Sesquipedalis(L.) Verd Field

This thesis came from the project "Special Fund of Anhui Province Governor(y47)—integrated pest management and application for the non-environment damage vegetables",strived to discover the traits of arthropod community in Vigna unguiculata W. ssp.sesquipedalis(L.) Verd 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 2006,arthropods got 67 species which belonged to 49 families,phytophage was prominent part,its relative abundance was 0.9055,dominant species was Bemisia tabaci and Aphididae;and that of predacious sub-community was 0.0853,dominant species was Aphididae and Bemisia tabaci;In 2007,arthropods got 66 species belonged to 49 families,phytophage was prominent part,its relative abundance was 0.7784,dominant species was Aphididae and Bemisia tabaci;and that of predacious sub-community was 0.1773,dominant species was Aphididae and Bemisia tabaci;Dominant concentration and dominance in two years were compared and the result was phytophage community＞total community＞predacious sub-community,and result of the diversities indexes predacious community＞total community＞phytophage community;The result of the above in two years was same,which was caused by large number of the dominant population.(2) Caused by interaction of pest,natural enemy and climate factors,indexes of every communities fluctuated.Change tendency of diversity index in 2006 in total community was:low-high-low;Change tendency of diversity index in 2007 was low-high-low-high -low-high:and so did phytophage community,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.Evenness had close relationship with diversity indexes in total community;richness,species numbers,dominant concentration,dominance all influenced diversity indexes;Individual number had close relationship with diversity indexes in phytophage sub- community in 2006. Evenness had close relationship with diversity indexes in phytophage sub- community in 2007,and so did predacious sub-community as total community.(4) Total community and phytophage,predacious community in two years were analyzed by clustering.The result in 2006:The total community was divided into 5 clusters when D is 0.94;the phytophage community was divided into 4 clusters when D is 0.93;the predacious was divided into 4 clusters when D is 0.89.And the result in 2007:The total community was divided into 4 clusters when D is 0.952;the predacious was divided into 5 clusters when D is 0.913.The clustering result of the optimization partitions in the arthropod total communities in 2006 was 7.7,7.14～7.21,7.28～8.4,8.11～8.25;which in 2007 was 4.30～5.14,5.21,5.28～6.4,6.11～6.25,7.2,7.9.(5) The characteristic parameters of arthropod community and its phytophagous,predacious sub-community in Vigna unguiculata W.ssp.sesquipedalis(L.) Verd field in two years were analyzed with the method of principal component analysis.The results showed that in 2006:in the first principal component,the contribution of arthropod community,phytophagous sub-community and predacious sub-community in Vigna unguiculata W.ssp.sesquipedalis(L.) Verd field was 78.14%,79.40%,64.78%respectively. For the three kinds of communities,the absolute values of normalized regressive coefficient of Hill diversity index H,Pielou evenness(J),species numbers S and richness R were larger,indicating that diversity index H,species numbers S and richness R had greater contribution;in 2007:in the first principal component,the contribution of arthropod community,phytophagous sub-community and predacious sub-community in Vigna unguiculata W.ssp.sesquipedalis(L.) Verd field was Hill diversity index H,Pielou evenness(J) and richness R respectively.For the three kinds of communities,the absolute values of normalized regressive coefficient of Hill diversity index H,Pielou evenness(J) and richness R had greater contribution.(6)Systematical investigation on populations dynamics of Bemisia tabaei and its 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 indicated that Misumenops tricuspidatus(Fabricius),Therdion octomaculatum Boes. et Str were the major enemy affecting Bemisia tabaci in 2006and2007.(7) The temporal niche overlap of Bemisia tabaci ane its natural enemies were analyzed. The result is the Clubionajaponicola,Tetragnathajaponica,Propylaea japonica (Thunberg),Orius agilis(Flor) in 2006 and Therdion octomaculatum Boes.et Str,Orius agilis(Flor),Clubionajaponicola had high overlap grad with Bemisia tabaci in 2007,they were its main natural enemies.