【作者】 穆兰芳；

【导师】 董双林；

【作者基本信息】 南京农业大学 ， 农业昆虫与害虫防治， 2005， 硕士

【摘要】 转Bt基因棉花(简称Bt棉)的大面积推广和应用,对有效控制近年棉铃虫的发生和为害起到了重要作用。然而Bt棉仍存在两个突出的问题:其一是Bt棉对棉铃虫的抗性在后期下降问题;其二是棉铃虫的抗性风险问题。本研究即针对这两个问题,从昆虫一生最薄弱的环节——两性间的求偶和交配着手,通过研究棉铃虫性信息素通讯系统在不同情况下的变化,以期为生产上利用性信息素等行为调控技术防治Bt棉后期棉铃虫的为害;为合理设置、利用和评价“庇护所”措施,防止棉铃虫对Bt棉产生抗性,提供理论参考。研究分为两部分:1)研究Bt毒素(与Bt棉中的相同)处理棉铃虫3龄幼虫至化蛹后对存活成虫性信息素通讯系统的影响;2)比较Bt棉抗感棉铃虫品系(室内筛选品系)间性信息素通讯系统的差异。主要研究结果如下: 1.Bt毒素处理棉铃虫幼虫后对存活成虫性信息素通讯系统的影响 (1)Bt毒素处理棉铃虫3龄幼虫至化蛹后,使存活雌蛾的求偶百分率、求偶起始时间和求偶持续时间减少。处理雌蛾的求偶起始时间,在第3和第4个暗期分别为3.25±0.93和4.07±0.91hr,而对照雌蛾分别为2.5±0.84和3.45±0.97hr,差异显著;求偶持续时间在7个暗期均差异极显著,7个暗期中处理雌蛾的求偶持续时间分别为1.8±0.61、3.1±0.56、4.25±1.04、3.53±0.74、2.43±0.76、2.05±0.74和1.12±0.36hr,对照雌蛾分别为3.15±0.73、4.25±0.70、5.57±0.89、4.18±0.92、3.3±0.81、2.73±0.80和2.25±0.92hr。Bt毒素对雌蛾的求偶节律(包括时节律和日节律)没有影响,求偶高峰期均为第三个暗期的8-9小时。 (2)Bt素处理棉铃虫3龄幼虫至化蛹后,存活雌蛾性信息素组分Z11-16∶Ald和Z9-16∶Ald的滴度均有不同程度的降低。存活雌蛾两种性信息素组分的滴度分别为42.88±12.86和3.30±0.84ng/♀,而对照雌蛾分别为47.45±3.91和3.76±0.46ng/♀,Z9-16∶Ald的滴度差异显著。存活雌蛾性信息素组分Z11-16∶Ald和Z9-16∶Ald的滴度比例为12.99±2.17,对照为12.70±1.21,差异不显著。 (3)Bt素处理棉铃虫3龄幼虫至化蛹后,存活雄蛾对不同剂量的性信息素二元混合物的EAG反应值均有不同程度的增加。处理雄蛾对不同剂量(1、10、100、1,000、10,000和100,000ng)的性信息素二元混合物(Z11-16∶Ald∶Z9-16∶Ald=97∶3)的触角电位(EAG)值分别为7.31±1.63、8.84±2.67、9.73±2.59、12.72±2.22、15.47±3.65和18.61±3.84mV,对照分别为6.30±1.01、6.42±0.83、7.15±1.09、7.91±1.41、9.77±1.86和11.02±2.34mV,当刺激物剂量为1,000、10,000和100,000ng时,EAG反应差异极显更多还原

【Abstract】 Transgenic Bt cotton (Bt cotton) has been effectively used in many cotton-producing countries to prevent economic injury by H. armigera in fields in recent years. However, the most common used Bt cotton varieties now all over the world still have two serious problems: 1) the decreasing in resistance of the Bt cotton to H. armigera on later cotton development stage, when the 3rd and 4th generation bollworm occur in China, which made it needed to carry on the essential chemical spraying; 2) the resistance risk of H. armigera to the Bt cotton which threat the sustainable use of the Bt cotton as an effective means of cotton bollworm control. Our objectives of this study are aimed to elucidate 1) the effects of sublethal treatment of the cotton bollworm larvae (from 3-instar to pupation) with Cry 1 Ac toxin (same as that in Bt cotton) on the sex pheromone communication system, and 2) the variation of this communication system in resistant cotton bollworm strain to the susceptible one.The major results for the first part of the researches are:1. The calling behavior of female survivors from the artificial diet containing sublethal dose of Bt toxin is suppressed. The calling percent, the mean onset time of calling and the mean time spent calling of survivors are all decreased over the first to seven scotophases, especially significant difference in 3rd and 4th scotophases for the mean onset time of calling (P<0.05) and in all 7 scotophases for the mean time spent calling (P<0.01). In the 3rd and 4th scotophases, the mean onset time of calling of female survivors is 3.25±0.93 and 4.07±0.91 hr after the initiation of scotophase, whereas that of control is 2. 5±0.84 and 3.45±0.97hr, respectively. In all 7 scotophases, the mean time spent calling of female survivors are 1. 8±0.61, 3.1±0.56, 4.25±1.04, 3.53±0.74, 2.43±0.76, 2.05±0.74 and1.12±0.36hr; whereas that of control are 3.15±0.73, 4.25±0.70, 5.57±0.89, 4.18±0.92, 3.38±0.81, 2.73±0.80 and 2.25±0.92hr, respectively. However, the calling periodicities (day periodicity and hour periodicity) of both control and treated females are same, with the peak calling time at 8-9 hr after the initiation of 3rd-scotophase.2. The titers of sex pheromones produced by female survivors from the artificial diet containing sublethal dose of Bt toxin are decreased, but not significantly different to thecontrol for Zll-16:Ald. The titers of Zll-16:Ald and Z9-16:Ald females are 47.45±3.91 and 3.76±0.46ng/(?) in control, and 42.88±12.86 and 3.30±0.84 ng/(?) in female survivors, respectively. Similarly, the ratio of Zll-16:Ald to Z9-16:Ald is not significantly different between control (12.70±1.21) and female survivors (12.99±2.17).3. The EAG responses of male survivors to a series dosages of binary sex pheromone mixtures ( 1, 10, 100, 1 000, 10 000 and 100 000ng) increase to 7.31±1.63, 8.84±2.67, 9.73±2.59, 12.72±2.22, 15.47±3.65 and 18.61±3.84mV from 6.30±1.01, 6.42±0.83, 7.15±1.09, 7.91±1.41, 9.77±1.86 and 11.02±2.34mV in control, respectively. When the dosage are 1 000ng and above, the EAG responses between them are significant difference(P<0.01).4. The behavioral response in wind tunnel to sex pheromone lure (300ng) of male survivors is slightly increased than the control males, but there are no significant difference in regard to the percentages of ’taking flight’, ’orientation’, ’up-wind flight’, ’approaching’ and ’contacting’ behaviors.5. Assortative mating between control and survivor cotton bollworms indicated there is no evidence for assortative mating between them.In the second part of this research, we have carried on a comparative study on the difference of sex pheromone communication systems between Bt cotton-susceptible (S) and Bt cotton-resistant (R) H. armigera The major results as follows:1. The calling behaviors of S and R female are similar not only in the calling periodicities (day periodicity and hour periodicity) with the peak calling time at 8-9 hr after the initiation of 3rd-scotophase, but also in the calling percent, the m更多还原