Biocontrol agents are critical for pest management in sustainable agriculture. Generalist arthropod predators may hold a great potential as biocontrol agents because they are ubiquitous and consume pests in agroecosystems. However, their diet composition over the entire crop season has rarely been quantified, which hinders our ability to assess their biocontrol potential in real field conditions that foster temporal dynamics of pest and alternative prey populations. To fill this knowledge gap, we surveyed arthropod communities over crop stages in organic and conventional rice farms (n = 7 each) and used stable isotope analysis (δ¹³C and δ¹⁵N) to quantify the diet composition of generalist arthropod predators over time. We aimed to (1) examine the resource partitioning (trophic niches) in these predators, (2) quantify these predators’ diet composition from potential prey sources (rice herbivores, tourist herbivores, and detritivores), and (3) investigate the effects of farm type (organic/conventional) and crop stage (tillering/flowering/ripening stage) on pest (rice herbivore) consumption by the predators. The results show that generalist predators in both organic and conventional farms shifted trophic niches over the crop season and consumed a higher percentage of rice herbivores at late than at early crop stages (e.g., 90–93% at ripening vs. 34–55% at tillering), suggesting an increasing biocontrol value over time regardless of farm type. Surprisingly, generalist predators consumed higher proportions of rice herbivores in conventional than organic farms at tillering and flowering stages, highlighting their underappreciated potential as biocontrol agents in conventional farms. These results demonstrate that although generalist arthropod predators do consume non-pest alternative prey, they have a high biocontrol potential (per capita pest consumption) in both organic and conventional rice farms. We encourage modern agriculture to develop techniques to support robust populations of these predators and the ecosystem services that they provide.

中文翻译：

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在有机和传统农场中，多才多艺的节肢动物捕食者的害虫消耗随着作物阶段的增加而增加

生物防治剂对于可持续农业中的害虫管理至关重要。多才多艺的节肢动物捕食者可能具有作为生物防治剂的巨大潜力，因为它们无处不在，并以农业生态系统中的害虫为食。然而，它们在整个作物季节的饮食成分很少被量化，这阻碍了我们在实际田间条件下评估它们的生物防治潜力的能力，这些条件促进了害虫和替代猎物种群的时间动态。为了填补这一知识空白，我们调查了有机稻田和传统稻田（ 每个n = 7）作物阶段的节肢动物群落，并使用了稳定同位素分析（δ ¹³ C 和 δ ¹⁵N）随着时间的推移量化多面手节肢动物捕食者的饮食组成。我们的目的是（1）检查这些捕食者的资源分配（营养生态位），（2）量化这些捕食者的潜在猎物来源（水稻食草动物、旅游食草动物和碎屑动物）的饮食组成，以及（3）调查捕食者对害虫（水稻食草动物）消耗的农场类型（有机/传统）和作物阶段（分蘖/开花/成熟阶段）。结果表明，有机农场和传统农场中的多面手捕食者在整个作物季节都改变了营养生态位，并且在后期比早期作物阶段消耗了更高比例的稻草食草动物（例如，成熟时为 90-93%，而在成熟时为 34-55%）。分蘖），表明无论农场类型如何，生物防治价值都会随着时间的推移而增加。出奇，在分蘖和开花阶段，通才掠食者在传统农场中消耗的水稻食草动物比例高于有机农场，这突显了它们作为传统农场中生物防治剂的潜力未被充分重视。这些结果表明，虽然多才多艺的节肢动物捕食者确实消耗非害虫替代猎物，但它们在有机和传统稻田中都具有很高的生物防治潜力（人均害虫消耗量）。我们鼓励现代农业开发技术来支持这些捕食者的强大种群及其提供的生态系统服务。这些结果表明，虽然多才多艺的节肢动物捕食者确实消耗非害虫替代猎物，但它们在有机和传统稻田中都具有很高的生物防治潜力（人均害虫消耗量）。我们鼓励现代农业开发技术来支持这些捕食者的强大种群及其提供的生态系统服务。这些结果表明，虽然多才多艺的节肢动物捕食者确实消耗非害虫替代猎物，但它们在有机和传统稻田中都具有很高的生物防治潜力（人均害虫消耗量）。我们鼓励现代农业开发技术来支持这些捕食者的强大种群及其提供的生态系统服务。