The principles of organic production are based on the respect of ecological processes including the promotion of natural enemies to control pests. However, as a last resort, some natural pesticides can be applied such as the pesticide spinosad. This neurotoxic insecticide is now widely used even in non-organic production systems. As generalist predators, spiders, and especially orb web spiders, which prey on flying pests, are thought to be useful for biocontrol. To study the effects of spinosad on orb web spiders, we applied spinosad (Success4®) at the normal application rate (96 g ha-1) in an orchard covered by nets where Araneus diadematus was very abundant. Its abundance (number of webs), location when present on the web and web characteristics were determined one day before (D - 1) and 1, 3, 6, 10 and 14 days after the application (D + 1, D + 3, D + 6, D + 10 and D + 14). After spinosad application, at D + 1 and D + 14, the number of A. diadematus webs decreased by 28% and 47%, respectively, compared to D - 1 where we observed on average 0.2 webs m-2. This decrease is likely due to a combination of direct pesticide effects, reduced prey availability and mechanical effects of the air blast sprayer. The short-term toxicity of spinosad was assessed using behavioural markers: (i) the percentage of abnormally located spiders (i.e. neither in the centre of the web nor hidden under the apple leaves) for 30 and 50% of the webs at D + 1 and D + 3 respectively, (ii) the percentage of incomplete webs (made only of the non-sticky spiral) in 35 and 75% of the cases at D + 1 and D + 3 respectively and (iii) one web characteristic, the mean parallelism between spirals, that was significantly reduced at D + 1 compared to D - 1. The study of the other web characteristics indicated that spiders did not modify the capture area but rather significantly decreased their investment in silk at D + 6 and D + 10 by reducing the number of radii and spiral turns. Overall, the application of spinosad (Success4®), representing a triple disturbance (mechanical, toxicological and alimentary), has a negative impact on the orb web spider A. diadematus and should thus be used with caution if growers want to promote the contribution of these spiders to natural biocontrol in their fields.

中文翻译：

---

在苹果园中应用多杀菌素会影响蜘蛛Araneus diadematus的丰度及其网状构造行为。

有机生产的原则基于对生态过程的尊重，包括促进天敌控制害虫。但是，作为最后的手段，可以使用一些天然农药，例如杀虫剂多杀菌素。这种神经毒性杀虫剂现在甚至在非有机生产系统中也被广泛使用。作为多面手的食肉动物，蜘蛛，尤其是以飞虫为食的球网蜘蛛被认为可用于生物防治。为了研究多杀菌素对球网蜘蛛的影响，我们以正常施药量（96 g ha-1）将多杀菌素（Success4®）施用在Araneus diadematus含量很高的网覆盖的果园中。它的丰度（网的数量），出现在网上的位置和网的特性是在施用前一天（D-1）和施用后的1，3、6、10和14天（D + 1，D + 3，D + 6，D + 10和D + 14）。施用多杀菌素后，在D +1和D + 14时，与我们平均观察到0.2个网片m-2的D-1相比，A。diadematus网片的数量分别减少了28％和47％。这种减少可能是由于直接的杀虫剂作用，减少的猎物可利用性和鼓风喷雾器的机械作用共同造成的。使用行为标记评估了多杀菌素的短期毒性：（i）30％和50％的网在D + 1时异常定位的蜘蛛（即既不在网中心也不在苹果叶下的百分比）的百分比和（D + 3），（ii）在D + 1和D + 3的情况下，分别有35％和75％的情况下不完整网（仅由非粘性螺旋制成）的百分比，以及（iii）一种网的特性，螺旋之间的平均平行度，与D-1相比，在D +1时显着减少。研究其他网状特征表明，蜘蛛并没有改变捕获面积，而是通过减少数量而大大减少了在D + 6和D + 10时对丝的投资。半径和螺旋圈。总体而言，多杀菌素（Success4®）的使用代表了三重干扰（机械，毒理学和营养），对球网蜘蛛A. diadematus具有负面影响，因此，如果种植者希望促进果蝇的生长，应谨慎使用。这些蜘蛛在他们的领域进行自然生物防治。对其他网状特征的研究表明，蜘蛛并没有改变捕获面积，而是通过减少半径和螺旋圈数，显着减少了在D + 6和D + 10时对丝的投资。总体而言，多杀菌素（Success4®）的使用代表了三重干扰（机械，毒理学和营养），对球网蜘蛛A. diadematus具有负面影响，因此，如果种植者希望促进果蝇的生长，应谨慎使用。这些蜘蛛在他们的领域进行自然生物防治。对其他网状特征的研究表明，蜘蛛并没有改变捕获面积，而是通过减少半径和螺旋圈数，显着减少了在D + 6和D + 10时对丝的投资。总体而言，多杀菌素（Success4®）的使用代表了三重干扰（机械，毒理学和营养），对球网蜘蛛A. diadematus具有负面影响，因此，如果种植者希望促进果蝇的生长，应谨慎使用。这些蜘蛛在他们的领域进行自然生物防治。