Data from: Biological control in winter: novel evidence for the importance of generalist predators

1. The role of generalist predators in pest control has been neglected because generalists are not able to track pest populations. Generalist predators are suggested to be important in spring before specialist predators become active. 2. Here, we show that some generalist predators are important even during winter, when the majority of arthropod pests and their enemies are dormant. We quantified the role of winter-active generalist predators on the suppression of pear psylla during winter using a discrete nonlinear model of an intraguild predation system. 3. To parameterize our model, we conducted a series of experiments on (i) functional responses, (ii) prey preferences and (iii) ontogenetic development and made observations on the population densities of spiders and potential prey. We ran the model for different winter scenarios, that is, for very cold and very warm winters. 4. Synthesis and applications. We found that winter-active predators considerably suppressed the pear psylla population. Predators exerted a stronger effect in a warmer winter than in a colder one. Orchard growers thus should avoid use of non-selective pesticides during this period and instead aim to support the community of generalist predators. Our results suggest more attention should be given to encouraging generalist predator populations in other systems, even in periods when crops are not producing.1. 广食性捕食者（generalist predators）在害虫防治中的作用长期被忽视，原因在于这类捕食者无法追踪害虫种群的动态。已有研究指出，广食性捕食者在专食性捕食者（specialist predators）活跃前的春季就已发挥重要作用。 2. 本研究证实，部分广食性捕食者即便在多数节肢动物害虫及其天敌处于蛰伏状态的冬季，仍可发挥关键作用。我们借助集团内捕食系统（intraguild predation system）的离散非线性模型，量化了冬季活跃的广食性捕食者对梨木虱（pear psylla）的种群抑制效应。 3. 为完成模型参数化，我们开展了一系列实验：(i) 功能响应（functional responses）测定、(ii) 猎物偏好（prey preferences）分析以及(iii) 个体发育（ontogenetic development）观察，并对蜘蛛及其潜在猎物的种群密度进行了监测。我们针对不同冬季情景（即极寒冬季与极暖冬季）运行了该模型。 4. 综合与应用。本研究发现，冬季活跃的捕食者可显著抑制梨木虱种群，且在暖冬环境中的抑制效果强于寒冬。因此，果园种植者应避免在此期间施用非选择性农药，转而致力于保护广食性捕食者群落。本研究结果表明，即便在作物休耕期，也应更加关注其他生态系统中广食性捕食者种群的培育与保护。