Esteves Filho Alberto B, de Oliveira José V, Torres Jorge B, Gondim Manoel G C
Depto de Agronomia/Entomologia, Univ Federal Rural de Pernambuco, Recife, PE, Brasil, 52171-900.
Neotrop Entomol. 2010 May-Jun;39(3):338-44. doi: 10.1590/s1519-566x2010000300005.
The two spotted spider mite, Tetranychus urticae Koch, is a nontarget herbivore of Bt-cotton, but acquires and accumulates higher levels of Cry toxin than that expressed by transgenic plants. This work investigated the development and reproduction of T. urticae and of the predator Phytoseiulus macropilis Banks, during three successive generations looking for potential nontarget effect. In addition, behavioral studies on feeding preference, oviposition, and predation were carried out on Bt and non-Bt cottons. The development and reproduction of T. urticae and P. macropilis was conducted using leaf discs of Bt and non-Bt cottons. Arena containing leaf discs from both cotton types connected by a slide coverslip were also used in the behavioral studies. Averages of the three generations showed that the Bt-cotton does not affect the development, survival of immature stages, and reproductive output of T. urticae and of the predator P. macropilis. Furthermore, the preference for feeding and oviposition of T. urticae and P. macropilis were similar on both cotton types. In addition, P. macropilis exhibited similar predatory behavior on T. urticae fed on both cotton types. Levels of Cry1Ac toxin in T. urticae was 3.97 times greater than that found in the Bt-cotton plants as determined using a ELISA test. Despite of the amount of toxin acquired by the prey (T. urticae), no detectable levels of Cry1Ac were found in the predatory mite P. macropilis.
二斑叶螨（Tetranychus urticae Koch）是转Bt基因棉花的非靶标植食性害虫，但它获取并积累的Cry毒素水平高于转基因植物所表达的水平。本研究连续三代调查了二斑叶螨及其捕食性天敌加州钝绥螨（Phytoseiulus macropilis Banks）的发育和繁殖情况，以寻找潜在的非靶标效应。此外，还对二斑叶螨和加州钝绥螨在Bt棉花和非Bt棉花上的取食偏好、产卵和捕食行为进行了研究。利用Bt棉花和非Bt棉花的叶片圆盘对二斑叶螨和加州钝绥螨进行发育和繁殖研究。行为学研究中还使用了含有两种棉花叶片圆盘且由载玻片连接的饲养场。三代的平均值表明，Bt棉花对二斑叶螨和捕食性天敌加州钝绥螨的发育、未成熟阶段的存活以及繁殖产量均无影响。此外，二斑叶螨和加州钝绥螨在两种棉花上的取食和产卵偏好相似。另外，加州钝绥螨对取食两种棉花的二斑叶螨表现出相似的捕食行为。通过ELISA检测确定，二斑叶螨体内Cry1Ac毒素水平比Bt棉花植株中的高3.97倍。尽管猎物（二斑叶螨）获取了一定量的毒素，但在捕食性螨类加州钝绥螨中未检测到Cry1Ac毒素。
