Structure And Dynamics Of Arthropod Community In Different Transgenic Poplar-Cotton Eco-systems

The biological security problem has already been paid attention by more and more people today. Transgenic hybrid poplar741 and transgenic cotton have been developed and planted widely in recent years, as new genetic modified plants, their possible influence on arthropod community has been studied extensively, especially the transgenic poplar-cotton eco-system as the research object, and there has no related report at present. There were four different transgenic poplar-cotton eco-systems:Ⅰ,Ⅱ,Ⅲ,Ⅳ.Ⅰwere composed by non-transgenic hybrid poplar741(ⅠY)and non-transgenic cotton Xin Luzao-36(ⅠM),Ⅱwere composed by non-transgenic hybrid poplar741(ⅡY)and transgenic cotton Xin Luzao-36(ⅡM),Ⅲwere composed by transgenic hybrid poplar741(ⅢY)and non-transgenic cotton Xin Luzao-36(ⅢM),Ⅳwere composed by transgenic hybrid poplar741(ⅣY)and transgenic cotton Xin Luzao-36(ⅣM). And the arthropod community of the four different transgenic poplar-cotton eco-systems was investigated. Based on the methods of ecological community and system investigation, the effect of transgenic eco-system on the whole structure of arthropod community, the seasonal fluctuation of arthropod guilds and the similarity of arthropod community were evaluated in the transgenic eco-system in Zhuozhou, Hebei during 2009-2010, so as to provide the scientific foundations to the using and promotion of rational cultivation pattern persisting rational application of the transgenic poplar-cotton eco-system. The main results were as follows:(1) Impacts of transgenic poplar-cotton eco-system on arthropod community structure A total of 146663 arthropod individuals were found in the investigation of tow years. Transgenic poplar-cotton eco-system compared to the poplar-cotton eco-system have a good inhibitory action in herbivorous insect, but higher than the poplar-cotton eco-system in stick suction insect in 2009, and had a decreased trend in 2010; transgenic poplar-cotton eco-system had a more addition in the total number of predacitica natural enemy, but had a little effect in the total number of parasitical insect and neutral arthropod.ⅠM andⅠM were higher thanⅠM andⅠM in the individuals of Pest sub-community;ⅠM andⅠM were higher thanⅠM andⅠM in the individuals of predacitica natural enemy. The investigation of this two years of the poplars were different, on the whole, the structure of arthropod community had a certain melioration ofⅢY andⅣY. As anslysed from the character index, have the same results basically, at the same time, proved that the connection of arthropod community in poplar-cotton eco-system was complicated, and it need a further analysis and research.(2) Impacts of transgenic poplar-cotton eco-system on nutritional classes of arthropod community A higher abundance was found in transgenic poplar-cotton eco-system than in control poplar-cotton eco-system. According to the number of Lepidoptera pests, four systems were ranked as follows:Ⅲ﹥Ⅰ﹥Ⅱ﹥Ⅳ. On the individuals of the intermediate species and top species,Ⅰhad the dominant position, but in other insect groups, transgenic poplar-cotton eco-system had the dominant position;ⅠM andⅢM were higher thanⅡM andⅣM in the amount of Lepidoptera pests, as the intermediate species,ⅣM had the dominant position in the most functional group; then the Lepidoptera had a explosion in poplar in 2009,but reduced in 2010; on the individuals of intermediate species and top species, the structure of the arthropod community of the poplar had improved in 2010, and the abundance of most functional groups was higher.(3) Impacts of transgenic poplar-cotton eco-system on arthropod guilds dynamics In the course of time series, transgenic poplar-cotton eco-system show continuous resistance in 2010 compared to 2009, but in stick suction and other phytophagous insect, the transgenic poplar-cotton eco-system have little difference compared with control poplar-cotton eco-system; transgenic poplar-cotton eco-systemⅠshowed higher abundance on the number of predacitica natural enemy, parasitical insect and neutral arthropod consistently. The change of each cotton function groups is consistent in transgenic poplar-cotton eco-system. Transgenic cotton had significant resistance to herbivorous insect. But for stick suction and other phytophagous insect have no significant resistance. Transgenic poplar-cotton eco-system is higher at the number of predacitica natural enemy, but the compare poplar-cotton eco-system is dominant at the number of parasitical insect. The changes of the number of poplar forest function groups is not significant with time variation, In transgenic poplar forest, the occurred quantity of herbivorous insect is lower in 2010 than in 2009.(4) Similarity between arthropod communities among the four different transgenic poplar-cotton eco-systemsTwo years the similarity coefficient of the arthropod community in the four transgenic poplar-cotton eco-systems had the obvious contrast. On the whole, the whole effect of the transgenic poplar-cotton eco-systems showed the level of similarity of them were higher among them in 2009, but the similarity among each sample's was not obvious, but the similarity was notable in 2010, the transgenic plants(ⅠM—ⅠM,ⅠY—ⅠY)and the compare plants(ⅠM—ⅢM,ⅠY—ⅡY)get together by theirself, the result indicated that the structure of the arthropod community had improved in the small sample among the transgenic poplar-cotton eco-systems with the extension of time.