Studies On The Dynamics Of The Arthropod Communities In Oil Camellia Orchard In South Anhui

Based on the thorough investigation, the dynamics of the arthropod communities in oil camellia orchard and interaction of main insects with its natural enemies were studied by means of community analysis, grey system theory, path analysis and geostastics. These provided theory foundation for IPM.1 The arthropod community was divided into four sub-communities, which were phytophages, predators, parasitoids and neutralities. The results were showed 97 species of arthropod belonging to 77 families and 50 species of phytophages belonging to 46 families in oil camellia orchard. The relative abundance of phytophages was 0.55066. Toxoptera aurantii (Boyer de Fonscolombe), Stenocatantops mistshenkoi F. Willense and Cryptothelea minuscule Butler were dominant insects of phytophages. The relative abundance of predators was 0.39874. Pristomyrmex pungens Mayr and spiders were dominant enemies of predators. Dominance and dominant concentration of total communities were 0.074 and 0.063 respectively. Dominance and dominant concentration of every sub-community showed parasitoids >predators >phytophages.2 The seasonal dynamics of sub-communities was in consistent with the total community; the tendency during June to May was from high to low, to high again. Hill diversity index was in relation to species, individuals, dominance, dominant concentration, Pielou evenness and species richness. Hill diversity index was most relative with Pielou evenness, dominance and dominant concentration by path analysis. Principal components analysis coordinates analyzed indexes of communities; the results revealed diversity, evenness, species richness and dominant concentration were synthetic indexes of community construction. 3 Diversity indexes of arthropod communities were analyzed by clustering and optimization partitions. Total community, phytophages and predators sub-communities were divided into three stages according to different clustering distance. The optimization partitions in the arthropod total communities were 2003.6.03~10.16,11.18,2004.3.16~4.14 and 5.11.The result of the optimization partitions of phytophages sub-community was 2003.6.03~6.24,7.14~10.16,11.18and 2004.3.16~5.11. The result of the optimization partitions of predators sub-community was 2004.6.03,6.24,7.14~10.16 and 11.18~04.5.11.4 Study on the relationship of Cryptothelea minuscule Butler and its natural enemies by grey theory, the result showed Micryphantidae and Ichneumonidae were its ideal dominant enemies and Aarneidae , Tetragnathidae and Chalcidoidae were main enemies.5 The temporal niche breath and overlap of Cryptothelea minuscula Butler and its natural enemies, the vertical spatial breadth and overlap of them in different stage of oil camellia growth were analyzed. Cryptothelea minuscula Butler appeared in all stages of oil camellia growth evennessly, its temporal niche breadth was 0.802016. The niche breadth of Aarneidae was 0.73714 and was highest among all enemies; its niche overlap with Cryptothelea minuscula Butler was 0.80082;The fuzzy neartude of Cryptothelea minuscula Butler with Aarneidae was also highest. The synchronous effect was high between Cryptothelea minuscula Butler and Aarneidae. Aarneidae could follow simultaneously with Cryptothelea minuscule Butler.6 Study on spatial construction and relationship of Cryptothelea minuscule Butler and Aarneidae by geostastics from 3 June to 17 September and 16 March to 11 May, spatial construction of Cryptothelea minuscula Butler and Aarneidae showed aggregated distribution at different periods and its semi-variance models were spherical. The ranges of spatial dependence of Cryptothelea minuscula Butler and Aarneidae were 8.58~20.00 and 11.25~25.39 respectively. The value of spatial dependence was near at different period expect 11 May. These results showed Aarneidae followed with Cryptothelea minuscula Butler on populations and space. Therefore, Aarneidae was dominant natural enemy of Cryptothelea minuscula Butler.