Structure and dynamic changing patterns of arthropod community in transgenic Bt cotton and two traditional cotton fields
Using the systematic investigation in fields and community parameters analysis by one way ANOVA, studies for the structure and dynamics of arthropod community in the fields of transgenic Bt cotton Lumianyan 34F1(A), conventional cotton Sumian 12(B) and Zhongmian 19(C) were conducted. The results showed that in the whole cotton growth period, the relative abundance of arthropod sub-communities in pest insects, predators and neutral insects were A(92.1%)B(85.4%)C( 77.9%), A(1.4%)B(1.5%)C(2.8%), and A(6.5%)B(13.1%)C(19.3%), respectively. The pest insect species number of 7.3 ± 0.3 species / 10 plants in A was significantly lower than that of 11.3 ± 1.3 species / 10 plants in C. The individual number of total community in A was 21 827.3±7 293.4 individuals / 10 plants, which was significantly higher than that of 12 079.0±1 056.7 individuals / 10 plants in B and 7 302.3±1 423.8 individuals / 10 plants in C. The pest insect individual number in A was 20 101.3 ± 4 198.6 individuals / 10 plants, which was significantly higher than that of 5 690.6 ± 881.1 individuals /10 plants in C. The predator individual number of 298.0 ± 12.7 individuals / 10 plants in A was significantly higher than that of 185.3 ± 17.4 individuals / 10 plants in B. The individual number of dominant species enemy T. octomaculatum in A was 33.0±1.0 individuals / 10 plants, which was significantly lower than that of 45.0±2.6 individuals / 10 plants in C. The individual number of dominant species enemy P. japonica in A was 145.6±34.4 individuals / 10 plants, which was significantly higher than that of 67.6±7.7 individuals / 10 plants in B and 59.3±24.1 individuals / 10 plants in C. The individual number of target pest insect A. gossypii in A was 18 810.6±7 105.0 individuals / 10 plants, which was significantly higher than that of 9 164.0±786.0 individuals / 10 plants in B and 4 790.0±890.9 individuals / 10 plants in C. The dominant index of total community in A was 0.745 7±0.041 3, which was significantly higher than that of 0.600 1±0.017 6 in B and 0.485 0±0.019 3 in C. The diversity index of total community in A was 0.589 1± 0.080 5, which was significantly lower than that of 0.846 1±0.048 7 in B and 1.072 4±0.053 2 in C. The pest insects diversity index in A was 0.262 9±0.093 9, which was significantly lower than that of 0.469 1±0.131 4 in C. The evenness index of total community in A was 0.176 7±0.022 4, which was significantly lower than that of 0.246 5±0.009 3 in B and 0.307 8±0.014 7 in C.