Studies On The Dynamics Of The Arthropod Communities In Almond Orchard And The Interaction Relationship Between The Major Pests And Its Natural Enemies

Bsed on the thorough research,the dynamics of the arthropod communities in almond orchard and the interaction of the Empoasca flavescens(Fab.) with its naturalenemies were studied by means of the community analysis,multianalysis,path analysis and grey system theory etc..The conclusions were as follows.The arthropod commuities in almond orchard were divided into two sub-communities according to the constitution and the amount of species and different predator-prey relationships in the almond orchard.The results indicated that there were 59 species of arthropod belonging to 47families including 43 speices of neutral insects assigning to 33 families,16 spices of enemies representing 14 families in almond orchard.The relative abundance of Cicadelidae was the highest in enemies sub-community,0.969204.The dominant concentration and dominance of arthropod communities was 0.653546 and 0.689796.Dominant concentration,dominance,the evenness and the diversitied indexes of every communities were compared and the result was dominant concentration and dominance:total community＞pests-neutral＞natural enemies community;evenness and diversity index on the other way round natural enemies community＞total community＞pests-neutral insects.The diversities and evenness of every sub-communities was in consistent with the total community:the tendency was from low to high,to low,and then,to high,to low again.The diversity was a function of dominant,concentration species richness and the number of individuals;the main component affecting diversity was dominant concentration.The arthropod communities in almond orchard went through a succession that apparently changed from development to prosperity,then to depression.Analyzed the research results of every communities by system clustering, the results of total community and pests-neutral insects sub-community were divided into 4 clusters and that of natural enemies sub-community were divided into 3 clusters.The best temporal partitions in the arthropod total communities and natural enemies sub-community were 5 stages.The pests-neutral insects sub-community was 6 stages.Diversities of arthropod community in almond orchard were analyzed by path analysis.The results showed Hill diversity index of total community was more relative to evenness in almond orchard.So was the diversity of pests-nertral insects sub-community changes in diversity of natural enemies sub-community were contray to dominance and dominant concentration. The principal component analysis studied total community and sub-communities in almond orchard in order to find main factors.Concerning total community, accumulation contribution rate of the Three principal components was 99.7369.Acumulation contribution rate of the front three principal components about main pests and natural enemies were 98.3655%and 99.9087%respectively.Relational grade between ideal dominant enemies and Empoasca flavescens(Fab.) was analyzed by grey analysis.Relational between Empoasca flavescens(Fab.) and its natural enemies were Mantidea(0.5667)＞Coccinellidae(0.4172)＞Theridiidae (0.3818)＞Tetragnathidae(0.3758)＞Lycosodae(0.3629)＞Thomisidae(0.3398)＞Salticidae(0.3299)＞Micryphantidae(0.3163)＞Clubionidae(0.2187).The result showed the relational grade between Misunenops tricuspidatus and ideal enemies was highest,(0.5662).The following was Chrysopa septempunctata.Different pesticide(Ⅰ:Qiangxing andⅡ:Haoniandong) affected the individual number,diversity index and dominant concentration of arthropod community in almond orchard.The result showed:both kinds of pesticide affected the arthropod community.The individual number of pests and natural enemies was reducing.The pesticideⅡhas stronger effection.After 7 days of besprinkled,the losing rate of natural enemies reached 100%.