Effect Of Different Area Designs On The Researching Result Of Arthropod Community In The Paddy Fields

Rice is one of the crops which is most widely grown in China. Currently, there are many studies of diversity of arthropod community structure between different cultivation patterns or different varieties of rice, but lack of critical minimum area designs. In order to study the effct of different arera designs on the researching results of stability and diversity of arthropod community, whcih is to determine the critical minimum area, to support the method of survey, to pick out the population dynamics of main pests and to make use of the natural control function of enemies. It is of great significance of sustainable production of rice. The main results were as follows:1. Comparisons of the stability and diversity of arthropod community sampled in rice plots of different area designsIn2012and2013, we sampled with five sub-samples in rice plots of different area designs by vacuum-suction machine. It was that there were no significant differences in common community indices such as species richness(S), Shannon-Wiener diversity index(H’), evenness index(J) and dominance index(C), were also found in the temporal dynamics of the four community indices of different area designs. All the similarity indices were higher than78%, showed the similar community compositions of the rice plots along different area designs.2. Comparisons on guild dominance of rice plots of different area designs of the arthropod communityIn2012and2013, it was showed that there were no significant differences on guild dominance in different area designs of the arthropod sampled by vacuum-suction machine with five sub-samples. The phytophages was the major class. And was found in the temporal dynamics of dominance in the phytophages, the parasitoids, the detritivores, the predators and the others. But the dominance of the phytophages sampled in300m2was significantly higher than that sampled in150m2and75m2On July16,2012. And the dominance of the parasitoids sampled in300m2was significantly higher than that sampled in150m2On September14,2012.3. Comparisons on dominant families and species of rice plots of different area designs of the arthropod community It was showed that there were no significant differences on dominant families and species in different area designs of the arthropod sampled by vacuum-suction machine with five sub-samples.And the highest-dominance families were the delphacidae, the chironomidae and the cicadellidae, meanwhile Sogatella furcifera, Inazuma dorsalis (Motschulsky) and Nilaparvata lugens were the highest-dominance species in2012and2013.4. Comparisons on the population densities and the temporal dynamics of the main arthropods in rice plots of different area designsWe selected the main phytophages (Sogatella furcifera, Nilaparvata lungens, Nephotettix cincticeps, Deltocephalus dorsalis) sampled by vacuum-suction machine with five sub-samples. It was showed that there were no significant differences in the population densities of the selected arthropods, were as the same the temporal dynamics in2012and2013.We selected the main predatorys (Crytorrhinus lividipennis, Paederus fuscipes Curtis, Hylyphantes graminicola, Marpissa magister) sampled by vacuum-suction machine with five sub-samples. It was showed that there were no significant differences in the population densities of the selected arthropods, were as the same the temporal dynamics in2012and2013. But the number of Hylyphantes graminicola sampled in300m2was significantly lower than that sampled in150m2in On August15,2012.We selected the main parasitoids (Haplogonatopus japonicus, Anagrus nilaparvatae, Apanteles schoenobii, Apanteles sp.) sampled by vacuum-suction machine with five sub-samples. It was showed that there were no significant differences in the population densities of the selected arthropods, were as the same the temporal dynamics in2012and2013.But the number of Haplogonatopus japonicus or Anagrus nilaparvatae sampled in300m2was significantly higher than that sampled in150m2On September14,2012.The above results indicts that the stability and diversity of arthropod community are similar and have no significant differences, but we need more area designs and sampling scales.