Effcets Of Marker-free Transgenic Cry1Ab Rice On Arthropod Communities In Paddy Fields

During2011, Effcets of marker-free transgenic cry1Ab rice on arthropod communities wereinvestigated at Wufeng and Shoushan Experimental stations, Fujian Province. The four treatmentswere set, which were the marker-free transgenic cry1Ab paddies (B4b68) and the control paddies(Minghui86) with or without pesticides. Minghui86is a non-transgenic rice isoline of B4b68.The results are as follows:1,B4b68paddies with pesticides had the lower species richness and individual abundanceof the arthropod community than the others, which showed significantly difference in Wufeng site.However, B4b68paddies without pesticides had the similar Shannon-Wiener index, Simpsonindex and evenness of the arthropod community to the other paddies. Both B4b68paddies withand without pesticides had no significant influence on the species composition, and thecompositions of the domninant species and the abundant species of the arthropod communities.2,B4b68paddies with pesticides had the lower individual abundance of the arthropodcommunity than the others, which showed significantly difference in Wufeng site. B4b68paddieswithout pesticides had the lower Shannon-Wiener index and Simpson index of the pest communitythan the others, which showed significantly difference in Wufeng site.3,Compared with the control paddies without pesticides, B4b68paddies with and withoutpesticides had positive or negative influences on the species richness, individual abundance,Shannon-Wiener index, Simpson index and evenness of the predatory arthropods on the differentsampling dates. However the influences were not significant. B4b68paddies without pesticideshad the higher Shannon-Wiener index, Simpson index and evenness of the predatory arthropodthan the others, and it can even increase the species richness at the middle and later growing stageof rice. The dominant species of the predatory arthropods in all the paddies were similar, and thesimilarity coefficients with each other were over than0.6.4, B4b68paddies with pesticides had the lower species richness of the parasitoidcommunity than the others, which showed significantly difference in Wufeng site, and itsindividual abundance was significant lower than the control paddies without pesticides. Thedominant species and abundant species varied among the treatment paddies. In B4b68paddies, allthe dominance indices of the obligate parasitoid against target pests, such as Telenomus sp.,Stenomesius sp., Tetrastichus purpureus and Stenomesius tabashii, were significantly lower thanthose in the control paddies. The results indicated that B4b68paddies without pesticides had negative effects on the parasitoid communities to some extent, while B4b68paddies withpesticides had more obviously negative effects.5,B4b68paddies with and without pesticides had no significant effects on the speciescomposition, dominant species and the characteristic indices of community structure of the neutralinsects. Similarity coefficients were higher among all the paddies, reaching more than0.8. All thepaddies shared more common species of the neutral insect, and Chironomidae was the mostimportant dominant species.In conclusion, marker-free transgenic cry1Ab rice (B4b68) had no significant effects on thearthropod communities in paddy fields, even though it had some negative effects on the parasitoidcommunities.