The Double Effects Of Transgenic Cotton On The Cotton Worm (Helicoverpa Armigera) And Its Two Parasites

Since the transgenic plants are common in the agricultural systems, the biosafety of them have gained the concern of many aspects. Many reports have showed that the transgenic plants have some disadvantages and potential influences on the non-target species, even the higher trophic level organisms, e.g. predators and parasites. In this paper, some experiments are planed to testify the potential risks of the transgenic cotton, which will afford the theoretical foundation to analyze and test the biosafety and potential environmental implications of the transgenic crop plant. In the experiments, the transgenic cotton "zhong kang 310" as the research aim and its parent's cotton "si mian 3" as control group are materials, and its direct effects on the cotton worm Helicoverpa armiger and indirect influences on its two parasites Microplitis mediator and Campoletis chlorida are tested. Several conclusions are as follows:1) The transgenic cotton has clearly inhibited the development of cotton worm. After the cotton worm is fed on the transgenic cotton, the growth speed of it begins to be slower, at 8th day, the weight of it is 22.0mg, while the cotton worm fed on the normal cotton, the weight of it is 105.9mg, the latter is 83.9mg higher than the former; then to 10th day, the difference of them has reached 136.6mg; In the other hand, the process of growth is always lower when the cotton worm is fed on the transgenic cotton, at 8th day, the average stage's grade of it is 1 1.4, while that of control group is 12.8.2) The transgenic cotton has disadvantageous effects on the development of population of the two parasites. When parasites have their eggs in the larva of cotton worm, which has been fed the transgenic cotton, cocooning rate of two parasites decline 26.5% and 18.5%, the average weight of the cocoon also declines 1.0mg and5.1mg, and the rate of the abnormal cocoon of Microplitis mediator inclines 23.2%. What's more, there are many abnormal larvae of parasites in the cotton worm.3) When cotton worm is fed on the transgenic cotton and is attracted by the parasite at the same time, it will be more inhabited and the death rate will be higher than that of any one independently. For example, the weight of cotton worm fed on the transgenic cotton is 22.0mg at 8th day, then Microplitis mediator has the effects on it, the weight of it is 12.4mg, the difference of them are 9.6mg, which is caused by the parasite; the same results have been gained by the Campoletis chlorida. The similar results can be seen in the number of blood cell of cotton worm.4) The insect cell line conditioned media can initiate the difference of the newly laid eggs of two koinobiotic endoparasitoid wasps Microplitis mediator (Hymenoptera: Braconidae) and Campoletis chloridae (Hymenoptera: Ichneumonidae) from neonate to germ band or hatch in vitro. The developing rate of Microplitis mediator in three insect cell line conditioned media is 93.3%, 86.3% and 60.0% respectively, the hatching rate of it is 77.2%, 80.0% and 16.7%; the developing rate of Campoletis chloridae is 92.2%, 86.7% and 43.1% respectively, the hatching rate of it is 94.8%, 93.6% and 20.0. but none of control group can be develop.5) When analyzing the indirect effects of the transgenic cotton on two parasites, we find the changing host's circumstances have the indeed disadvantage on them. The physical analysis shows: many physical standards have changed, which may be the real influence factors that inhibit the growth of two parasites. For example, the total protein content of cotton worm fed on the normal cotton is 265.8 ug/ml at 6day, while that of cotton worm fed on the transgenic cotton is 168.9 ug/ml, the latter has declined 36.5%; In addition, when cotton worm is to 9 stage grade (equal to the end of 3 stage), the blood numbers of cotton worm fed on the normal cotton is 458.7 /ul, while that of cotton worm fed on the transgenic cotton is 346.3 /ul, the latter has declined 24.5%.