1. Biological pest control is known to depend on landscape heterogeneity. However, such relationship shows irregular pattern and seems influenced by local farming practices and natural enemies that overwinter within crop fields. The objective of this study was to assess the contribution of emerging natural enemies in spring to biological control, and their response to the interaction between landscape heterogeneity and farming intensity.
2. We monitored the overwintering insect community using emergence traps and measured the local potential pest predation using prey cards in 30 cereal fields, in spring in France. Study fields were selected along a landscape heterogeneity gradient and farming practices were recorded.
3. None of the ten emerging taxa influenced predation of lepidopteran eggs or weed seeds. On the ground, aphid predation was positively correlated with emerging carabid beetles. In foliage, aphid predation was negatively correlated with emerging parasitoids. Overall, the community of natural enemies that overwinter within crop fields seemed to benefit from lower crop diversity and higher edge density in combination with higher farming intensities. This suggest that they represent a subset of species adapted to. This study highlights a large broad taxonomic panel of emerging natural enemies and their potential local pest predation.

中文翻译：

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春季谷物田出现的天敌可能有助于生物防治

1. 众所周知，生物害虫防治取决于景观异质性。然而，这种关系显示出不规则的模式，似乎受到当地耕作方式和在农田内越冬的天敌的影响。本研究的目的是评估春季新出现的天敌对生物控制的贡献，以及它们对景观异质性和耕作强度之间相互作用的反应。
2. 我们使用出苗陷阱监测越冬昆虫群落，并在法国春季使用猎物卡在 30 个谷类田地测量当地潜在的害虫捕食情况。研究领域是沿着景观异质性梯度选择的，并记录了耕作方式。
3. 十个新兴分类群中没有一个影响鳞翅目卵或杂草种子的捕食。在地面上，蚜虫捕食与新出现的甲虫呈正相关。在叶子中，蚜虫捕食与新出现的寄生蜂呈负相关。总体而言，在农田内越冬的天敌群落似乎受益于较低的作物多样性和较高的边缘密度以及较高的耕作强度。这表明它们代表了适应的物种的一个子集。这项研究突出了一个庞大的、广泛的新兴天敌分类小组及其潜在的当地害虫捕食情况。