Abstract: An investigation was conducted on the arthropod community on the plants (weeds, soybean, and sesame) at the margins of both organic farming paddy rice-duck field and conventional paddy field with wheat-rice rotation in East China across rice growth season. A total of 172 arthropod species belonging to 76 families, 12 orders, and 2 classes were collected, including 103 species of natural enemies (33 spiders, 6 predatory insects, and 64 parasitoid species) and 64 species of phytophagous insects. At the margins of organic farming paddy rice-duck field, the species richness and abundance of the spiders and insect natural enemies on the plants were >4.5 times and >1.5 times greater than those at the margins of conventional paddy field, respectively. The insect species richness at the margins of organic farming paddy rice-duck field was the highest on soybean and weeds (71), followed by on sesame (62), and the Shannon index was the highest on weeds; while at conventional paddy field margins, the insects on soybean had the highest richness (52) and Shannon index, and those on weeds had the smallest Shannon index. An obvious link was observed in the seasonal variations of the abundance between spiders and rice planthoppers on the weeds at organic farming paddy rice-duck field margins, but not observed at conventional paddy field margins probably due to the application of pesticides for the control of rice planthoppers. This investigation indicated that, compared with conventional paddy field, organic farming paddy rice-duck field was more beneficial to the protection of natural enemies, and planting soybean and sesame at conventional paddy field margins had positive effects on the conservation of arthropod community in paddy field.

Key words: Avicennia marina, Artificial wetland system, Cadmium, Distribution, Migration, Purifying effect