转Bt基因抗虫玉米对亚洲玉米螟幼虫取食行为的影响

室内研究了转cry1Ab杀虫蛋白基因的Bt抗虫玉米MON81 0和Bt1 1对亚洲玉米螟Ostriniafurnacalis初孵幼虫和3龄幼虫的取食行为、取食选择性和存活率的影响。在48h的非选择性试验中玉米螟初孵幼虫在MON81 0和Bt1 1玉米心叶组织上的幼虫取食率随时间的增加而下降,在对照玉米上的幼虫取食率随时间的增加而上升,两者间差异极显著。初孵幼虫接虫到MON81 0和Bt1 1玉米叶片48h的累计死亡率分别为67 .5 %和47 .5 % ,而在对照玉米上死亡率均为0. 3龄幼虫在Bt和非Bt玉米穗轴组织上的幼虫取食率随时间的增加呈上升趋势,第48h时在Bt和非Bt玉米上的幼虫取食率分别达到77 5 %和1 0 0 % ,差异极显著。选择性试验中,第4～48h内,初孵幼虫在Bt玉米上的幼虫取食率呈下降趋势,第48h时MON81 0和Bt1 1与各自非Bt对照的组合中初孵幼虫的累计死亡率分别为2 5 .0 %和1 7. 5 % ,二者差异不显著。3龄幼虫在Bt玉米和非Bt玉米上的幼虫取食率均随时间的延长而增加,但在非Bt玉米的幼虫取食率增加速度快,与Bt玉米差异极显著。Bt玉米对玉米螟幼虫取食有抑制和忌避作用。

Feeding behavior of Ostrinia furnacalis larvae on transgenic Bt corn expressing Cry1Ab toxin

Feeding behavior of the Asian corn borer (ACB) Ostrinia furnacalis (Guenée) neonates and the third instar larvae on transgenic Bt corn expressing Cry1Ab toxin from Bacillus thuringiensis and their survival were compared to the non-transgenic controls in laboratory bioassay. MON810 and Bt11 and their non-Bt corn controls, DK647 and NX4906, were used in the studies. In no-choice test, the percentage of neonates feeding on whorl leaf tissues of Cry1Ab-expressing decreased and was significantly less than those on non-Bt controls as the exposure time increased during the experiments. The cumulative mortality of neonates feeding on MON810 and Bt11 whorl leaf tissues was 67.5% and 47.5%, respectively, but no one died on non-Bt controls 48 h after infestation. In choice test, the percentage of neonates feeding on Bt whorl leaf tissues decreased as the time increased during the tests. The cumulative mortality of neonates feeding on the MON810 and Bt11 with their non-Bt whorl leaf tissues together was 25.0% and 17.5%, in 48 h after infestation respectively; no significantly difference was observed between the two Bt corns and their non-Bt controls. For the third instar larvae, the percentage of larvae feeding on young cob sections of either two Bt hybrids or non-Bt controls increased as the exposure time increased during the 48 h tests. The number of larvae feeding on non-Bt controls was significantly higher than that on the Bt hybrids. All of the third instars survived either on Bt or non-Bt corn leaf sections after a 48 h feeding period. Bt corn could effectively restrain the feeding of Asian corn borer larvae.