Non-random oviposition preference by target pest species on Bt and non-Bt refuge plants may increase the proportion of the population under selection pressure, reducing the value of the refuge strategy for resistance management. Here, we tested the oviposition preference for Bt over non-Bt plants and the damage-avoiding oviposition behavior of moths of the fall armyworm (FAW), Spodoptera frugiperda, a worldwide pest species with three reported cases of field-evolved resistance to Bt maize. In the greenhouse, choice assays indicated no oviposition preference for Cry1F Bt maize over its non-Bt isoline whatever intact or injured by FAW larvae. In a field experiment in a region of intensive agriculture in Brazil, the number of egg masses and FAW larvae was recorded on seven Bt maize varieties and two non-Bt maize varieties during vegetative and reproductive growth stages. There was only a weak oviposition preference by FAW moths for less damaged plants in the V10 stage. When using Cry1A.105 + Cry2Ab Bt maize and 50% refuge in a field experiment in another region in Southeastern Brazil, the number of egg masses on Bt and non-Bt plants also indicated no oviposition preference by the moths. Consistently, these results indicate that FAW moths do not distinguish Bt and non-Bt plants for oviposition and that conspecific larval damage has minor interference in the oviposition choice. Therefore, there seems to be random egg-laying preference of FAW moths in Bt maize fields, an oviposition behavior typical of generalist moth species and unlikely to be associated with the rapid selection of Bt-toxin-resistant FAWs.

中文翻译：

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秋季粘虫蛾的产卵行为不太可能损害转基因Bt作物的避难策略

Bt和非Bt避难植物对目标害虫物种的非随机产卵偏好可能会增加选择压力下的种群比例，从而降低了用于抗性管理的避难所策略的价值。在这里，我们测试了Bt在非Bt植物上的产卵偏好，以及秋天粘虫（FAW），斜纹夜蛾（Spodoptera frugiperda）的蛾类避免伤害的产卵行为。，是一种世界范围内的害虫物种，报告了三例对Bt玉米的田间进化抗性案例。在温室中，选择分析表明，无论完好或受一汽幼虫伤害，Cry1F Bt玉米都比其非Bt同种异型产卵。在巴西一个集约化农业地区的田间试验中，在营养和生殖生长阶段，记录了七个Bt玉米品种和两个非Bt玉米品种的卵量和一汽幼虫的数量。一汽蛾对V10阶段受损较少的植物只有较弱的产卵偏好。当在巴西东南部另一个地区的田间试验中使用Cry1A.105 + Cry2Ab Bt玉米和50％的避难所时，Bt和非Bt植物上的卵团数也表明蛾类没有产卵的倾向。一致地，这些结果表明，一胎蛾不能区分Bt植物和非Bt植物用于产卵，而同种幼虫对产卵的选择影响较小。因此，在Bt玉米田中，FAW蛾的产卵倾向是随机的，这是普通蛾类的典型产卵行为，不太可能与抗Bt毒素的FAW的快速选择有关。