Commonwealth Scientific and Industrial Research Organization (CSIRO), Entomology, 120 Meiers Road, Indooroopilly, Queensland 4068, Australia.
Ecol Appl. 2010 Dec;20(8):2322-33. doi: 10.1890/09-1278.1.
Agricultural pest control often relies on the ecosystem services provided by the predators of pests. Appropriate landscape and habitat management for pest control services requires an understanding of insect dispersal abilities and the spatial arrangement of source habitats for pests and their predators. Here we explore how dispersal and habitat configuration determine the locations where management actions are likely to have the biggest impact on natural pest control. The study focuses on the early colonization phase before predator reproduction takes place and when pest populations in crops are still relatively low. We developed a spatially explicit simulation model in which pest populations grow exponentially in pest patches and predators disperse across the landscape from predator patches. We generated 1000 computer-simulated landscapes in which the performance of four typical but different predator groups as biological control agents was evaluated. Predator groups represented trait combinations of poor and good dispersal ability and density-independent and density-dependent aggregation responses toward pests. Case studies from the literature were used to inform the parameterization of predator groups. Landscapes with a small nearest-neighbor distance between pest and predator patches had the lowest mean pest density at the landscape scale for all predator groups, but there can be high variation in pest density between the patches within these landscapes. Mobile and strongly aggregating predators provide the best pest suppression in the majority of landscape types. Ironically, this result is true except in landscapes with small nearest-neighbor distances between pest and predator patches. The pest control potential of mobile predators can best be explained by the mean distance between a pest patch and all predator patches in the landscape, whereas for poorly dispersing predators the distance between a pest patch and the nearest predator patch is the best explanatory variable. In conclusion, the spatial arrangement of source habitats for natural enemies of agricultural pest species can have profound effects on their potential to colonize crops and suppress pest populations.
农业害虫防治通常依赖于害虫捕食者提供的生态系统服务。为了控制害虫服务，需要适当的景观和生境管理，这需要了解昆虫的扩散能力以及害虫及其捕食者的源生境的空间配置。在这里，我们探讨了扩散和生境配置如何决定管理措施最有可能对自然害虫控制产生影响的位置。本研究侧重于捕食者繁殖之前的早期定殖阶段，以及作物中害虫种群仍然相对较低的时候。我们开发了一个空间显式模拟模型，其中害虫种群在害虫斑块中呈指数增长，而捕食者则从捕食者斑块在景观中扩散。我们生成了 1000 个计算机模拟景观，评估了四种典型但不同的捕食者群体作为生物防治剂的表现。捕食者群体代表了扩散能力和对害虫的密度依赖和密度独立聚集反应的差和好的特征组合。文献中的案例研究被用来为捕食者群体的参数化提供信息。对于所有捕食者群体，在害虫和捕食者斑块之间最近邻距离小的景观中，景观尺度上的平均害虫密度最低，但在这些景观内的斑块之间，害虫密度可能有很大的差异。移动性强且强烈聚集的捕食者在大多数景观类型中提供了最好的害虫抑制作用。具有讽刺意味的是，除了在害虫和捕食者斑块之间最近邻距离小的景观中，这一结果是正确的。移动捕食者的害虫控制潜力可以用景观中一个害虫斑块与所有捕食者斑块之间的平均距离来最好地解释，而对于扩散能力差的捕食者来说，害虫斑块与最近的捕食者斑块之间的距离是最好的解释变量。总之，农业害虫天敌的源生境的空间配置对它们定植作物和抑制害虫种群的潜力有深远的影响。
