Nitrogen fertilizers are widely used to maximize crop productivity but are also known to benefit pest insects. Here we show that nitrogen not only increased the egg size of the key pest, brown planthopper (BPH), Nilaparvata lugens Stål, but also benefitted the predatory mirid bug, Cyrtorhinus lividipennis Reuter (Hemiptera: Miridae). Predator nymph survival and development rate, female adult weight, longevity and fecundity were all enhanced. Importantly, however, high nitrogen levels also extended the predator handling time (Th), reducing the number of prey eggs attacked per predator and signalling a weakening of top-down control. We conclude that nitrogen fertilizer can exacerbate pest impact by natural enemy-mediated effects in addition to previously reported direct effects on herbivores. Our results highlighted the need to moderate the use of nitrogen fertilizers to maintain effective biological control of these rice pests to reduce dependence on insecticides, another potentially hazardous input.

中文翻译：

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水稻氮肥可提高食虫类捕食者的生态适应性，但可减轻其对猎物，稻褐飞虱，Nilaparvata lugens的影响

氮肥被广泛用于最大程度提高农作物的生产力，但也已知可以使害虫受益。在这里，我们表明，氮不仅增加了关键的害虫，褐飞虱（BPH）的鸡蛋大小，褐飞虱蝽，而且还受益掠夺mirid错误，黑肩绿盲较不安全路透社（半翅目：盲蝽科）。捕食者若虫的生存和发育速度，成年雌性体重，寿命和繁殖力均得到提高。然而重要的是，高氮水平也延长了捕食者的处理时间（Th），减少每个捕食者攻击的猎物卵的数量，并表明自上而下的控制能力减弱。我们得出的结论是，除了先前报道的对草食动物的直接影响之外，氮肥还可以通过天敌介导的作用加剧害虫的影响。我们的结果强调需要适度使用氮肥，以保持对这些水稻害虫的有效生物学控制，以减少对杀虫剂的依赖，而杀虫剂是另一种潜在的危险输入。