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为了更全面地评价转Bt基因作物对甜菜夜蛾Spodoptera exigua(Hbner)(鳞翅目:夜蛾科)的影响,在室内研究了甜菜夜蛾低龄幼虫连续6d取食含不同浓度Cry1Ac毒素的人工饲料后转移到不含毒素的饲料上,其生长发育与成虫繁殖的变化。结果表明:低龄幼虫取食含Cry1Ac的饲料6d内,校正死亡率随Cry1Ac浓度的升高以及取食时间的延长而升高。与一直取食不含Cry1Ac饲料的对照相比,取食含Cry1Ac饲料的幼虫体重显著下降;幼虫历期、预蛹期及雌雄蛹期均显著延长,但雌雄蛹重均与对照无显著差异;幼虫化蛹率显著下降,但羽化率与对照无显著差异;成虫产卵前期显著延长,产卵期与对照无显著差异,仅在5μg/g处理下较对照显著延长1.3d;每雌产卵量以10μg/g处理最高(719粒),但各处理均与对照无显著差异;雌蛾寿命均显著延长,而雄蛾寿命仅在最高浓度80μg/g下显著延长2.4d。这表明,尽管含不同浓度Cry1Ac毒素的饲料对甜菜夜蛾低龄幼虫有明显的生长发育抑制作用或导致死亡,但转移至不含毒素的饲料上取食后,幼虫能迅速恢复生长,顺利化蛹、羽化并产卵。因此,在转Bt基因作物田生长后期,甜菜夜蛾低龄幼虫取食表达Cry1Ac蛋白的组织若能存活并完成世代发育和繁殖,这无疑将增加甜菜夜蛾对Bt作物产生抗性的风险,因此亟需制定Bt作物生态系统中甜菜夜蛾的治理策略。
In order to evaluate the effects of transgenic Bt crops on Spodoptera exigua (Lepidoptera: Noctuidae) in a more comprehensive way, we investigated the effects of Cry1Ac toxins Of artificial feed after the transfer to non-toxic feed, its growth and development of adult reproductive changes. The results showed that the corrected mortality of young larvae fed Cry1Ac diet increased with the increase of Cry1Ac concentration and feeding time. The body weight of larvae fed Cry1Ac diet significantly decreased compared with the control without Cry1Ac feed. The duration of larvae, pre-pupal stage and male-female pupal stage were significantly prolonged, but the values of female and male pupal weight were not significantly different from those of control. Larvae pupation rate decreased significantly, but the emergence rate and no significant difference between the control; adult pre-oviposition significantly prolonged spawning period and the control no significant difference, only 5μg / g treatment significantly longer than the control 1.3d; (719 seeds) at 10μg / g, but no significant difference was found between the treatments and the control. The longevity of the female moths was significantly prolonged, while the male moths’ lives were prolonged by 2.4 days at the highest concentration of 80μg / g. This indicates that although the diet containing different concentrations of Cry1Ac toxins showed obvious growth and development inhibition or death to the beet armyworm larvae, the larvae could recover quickly after being transferred to the non-toxin feed, , Emergence and oviposition. Therefore, in the late growth stage of transgenic Bt transgenic plants, the survival of the tissues of Cry1Ac expressing Cry1Ac by the larvae of C. hellens larvae will survive and complete the generational development and reproduction, which undoubtedly increases the risk of S. beetle producing resistance to Bt crops There is an urgent need to develop a strategy for the control of beet armyworm in Bt crop ecosystems.