[Community structure and its dynamics of predatory arthropod in different tobacco varieties fields]

With principal component analysis and using community structural characteristic indices, this paper studied the community structure and its dynamics of predatory arthropod in fields planted with tobacco varieties Nc89, Nc82 and K326. The results showed that in all test fields, spiders and predatory insects were the predominant components of the predatory arthropod community, and their relative abundances were 83.25%-86.87% and 13.13%-16.38%, respectively. There was a significant difference in the mean density (individuals per 8 plants) of the most common predatory arthropod groups between different tobacco varieties fields, which was the highest in K326 field, followed by Nc82, and Nc89 field. The individuals of both Linyphiidae and Coccinellidae played the dominant role in the community. There was a significant difference in the richness of predatory arthropod community between Nc89 and Nc82 fields, but the differences of other structural characteristic indices were not significant. The temporal dynamics of the richness and dominancy in all test fields had a trend of low-high-low, and those of the diversity and evenness index were high-low-high.