转基因抗虫作物对非靶标昆虫的影响

Impact of the insect-resistant transgenic crops on non-target insects

转基因抗虫作物自 1996年被批准商业化种植以来 ,它的抗虫性和经济效益已得到了普遍肯定 ,同时 ,转基因抗虫作物对非靶标生物的影响 ,如转基因抗虫作物的长期种植 ,是否会导致次要害虫上升为主要害虫 ,是否会影响有益昆虫 ,包括重要经济昆虫、捕食性和寄生性天敌以及重要蝶类的种类及种群数量 ,已成为转基因抗虫作物生态风险评估的重要内容。一些研究结果表明 ,转基因抗虫作物在对靶标害虫有效控制的同时 ,一些对杀虫蛋白不敏感的非靶标害虫有加重危害的趋势 ,由于种植转基因抗虫作物 ,减少了化学农药的使用 ,客观上也使非靶标害虫种群数量上升 ,这对转基因抗虫作物害虫综合治理提出了新的要求。靶标害虫数量的减少直接影响了害虫天敌种群数量 ,靶标害虫取食转基因抗虫作物后发育迟缓 ,也间接影响了天敌昆虫的生长发育 ,转基因抗虫作物的花粉或花蜜是一些重要经济昆虫如蜜蜂、熊蜂和一些寄生蜂 ,甚至捕食性天敌的食物来源 ,或花粉飘落到一些鳞翅目昆虫如家蚕或重要蝶类昆虫的寄主植物上 ,直接或间接对这些昆虫造成一定影响。目前大多数研究表明转基因抗虫作物对非靶标昆虫 ,特别是对有益昆虫没有明显的不利影响 ,也有研究报道认为对某些有益昆虫有一定的不良影响。

Since the approval of transgenic crops resistant to insect pests for commercial production in 1996, it has been recognized and accepted widely for its excellent resistance to insects with good economic benefits. However, the impacts on non-target organisms which include the non-target insect pests, important economic insects, natural enemies and some butterflies, have become an important part of risk assessment of transgenic crops resistant to insect pests. Some reports showed that the target insects could be controlled effectively by transgenic crops resistant to insects, but the population of the secondary insects which are not susceptible to the expressed toxins in plant increased and also owing to the decreased chemical uses. Direct effects are that the population of some natural enemies decreases as the population of target insects decreased in transgenic crops resistant to insects. Indirect effects are that the development of the natural enemies lowered as that the target insects growth were retarded when fed on transgenic crops. The pollen or nectar of some transgenic crops resistant to insects are food sources for some important economic insects, such as honey bees, bumble bees, some parasitoids and predators, and also some pollen deposited on food plants of silkworms or some important butterflies, which could have direct or indirect effects on these beneficial insects. Most reports indicated that the transgenic crops resistant to insects do not have side effect on non-target insects, especially the beneficial insects, but some side effects also reported. It will be helpful to evaluate the ecological risks of the transgenic crops resistant to insects and take full advantage of the transgenic crops in IPM.