Ecology Of Arthropod Community In Orchards

The advance on arthropod community was systemically reviewed in the thesis. The summary and prospect of arthropod community as well integrated pest control in orchards were summed up. According to the investigation, field and indoor trial, by using knowledge and technique of ecology, taxonomy statistics and computer etc, the results were as follows: 1. The structure and dynamics of the arthropod community in orchards was investigated, identified, classified and analyzed from 2001 to 2003 in Shanxi. 178 species belonged to 4 classes, 19 orders and 86 families were discovered in the orchards, including 18 species of predators representing 9 families, 6 orders; 68 species of spiders representing 14 families; 14 species of parasitorids presenting 6 families, 2 orders; 69 species of phytophages presenting 49 families, 7 orders; 6 species of neutralities presenting 6 families; 2 species of other arthropods. According to nutritional and feeding relationship, the arthropod community was divided into 4 sub-communities and 6 functional groups, the relative abundance of the 4 sub-communities was respectively 38.2% of phytophages, 48.42% of predators including 38.2% of spiders, 7.87% of parasitorids and 3.37% of neutralities. Dominant species of phytophages were Pentatomidae, mites, aphids and insect scales; of natural enemies were Anthocoridae, Syrphidae,Chrysopidae and spiders in apple orchards. By the analysis of number dynamics, ecological dominance and diversity of the functional groups, the results showed that the structure of arthropod communities in the orchards was relatively stable. It was obvious that natural enemies were able to control pests effectively. 2. The structure of weed communities in orchards which many arthropods dwelled was studied, and there were 98 species belonged to 28 families in apple orchard. The temporal dynamics of individual number, species abundance and diversity of both weed and arthropod communities were dealt with, and it was also analyzed that the arthropod communities characteristics index were affected by the corresponding index of weed communities, and the change trend of the first and second dominant species both weed and arthropod communities in all of five kinds of orchards were similar. The cluster analysis indicated that there existed similarity on the time dynamics of weed and arthropod communities in various orchards to some extent, however not very significant. 3. Investigation from April to Sept. 2002 on structure and temporal dynamics in the orchards were conducted with the optical sorting methods and principal component analysis. The results showed that three stages according to the time sequence and the distinguishing feature of fruit trees'development were divided, as well as major characteristics and occurrence dynamics of each stage was revealed. the dominant pests and natural enemies in each stage and their predominant role in arthropod communities of orchards were clear and definite. 4 The structure and relative abundance of spider sub-community of apple orchard were carried out, After primarily classification and authenticating in lab, there were 68 species belong to 48 geneses, 15 families, and among them 43 species were new record in Shanxi . The dominant species in apple orchards were Oedothorax feminea, Pardosa astrigera,Phiodromus cespitum,ysticus ephippiatus. Change of time pattern of the species richness(s), total individual number(n), index of diversity(h), and evenness(e) were preliminarily studied by using multiple stepwise regression analysis, the results showed that in early and medium-term of growth of apple tree, the main factor affecting the diversity of spiders was evenness and in lopper it was the species richness. Calculation result of spatial pattern for time, space and three dimension(time-vertical and level space) showed that the spatial pattern of spiders in apple orchards all belonged to aggregated distributions. 5.the study of neutral insect sub-community was carried out, it was showed that neutral insect whose relative abundance was more than 10% was one of important parts and playing an undoubtedly role in the arthropod community of orchards. Meanwhile, the occurrence tendency of the neutral insect which accompany with the occurrence of natural enemy was somewhat earlier than the dominant pest, which could, to some extent, make up with the defect of natural enemies who take place always behind the pests in the natural situation. The study on time niche among three natural enemies and neutral insects showed that encounter opportunity of three natural enemies to Chironomidae, Phoridaec, Ephydridae and Calliphoridae in time sequences was larger. And That is to say, the neutral insect has active effect to maintain the population of natural enemies in the orchard. The principal component analysis was used to explore the neural insect's function in the community, a conclusion was drawn that predominant effect of neutral insects was more scattered and they played the role by the functional group. Through the calculation of grey...