Data from: Disentangling mite predator-prey relationships by multiplex PCR

Gut content analysis using molecular techniques can help elucidate predator-prey relationships in situations in which other methodologies are not feasible, such as in the case of trophic interactions between minute species such as mites. We designed species-specific primers for a mite community occurring in Spanish citrus orchards comprising two herbivores, the Tetranychidae Tetranychus urticae and Panonychus citri, and six predatory mites belonging to the Phytoseiidae family; these predatory mites are considered to be these herbivores’ main biological control agents. These primers were successfully multiplexed in a single PCR to test the range of predators feeding on each of the two prey species. We estimated prey DNA detectability success over time (DS50), which depended on the predator-prey combination and ranged from 0.2 to 18 h. These values were further used to weight prey detection in field samples to disentangle the predatory role played by the most abundant predators (i.e. Euseius stipulatus and Phytoseiulus persimilis). The corrected predation value for E. stipulatus was significantly higher than for P. persimilis. However, because this 1.5-fold difference was less than that observed regarding their sevenfold difference in abundance, we conclude that P. persimilis is the most effective predator in the system; it preyed on tetranychids almost five times more frequently than E. stipulatus did. The present results demonstrate that molecular tools are appropriate to unravel predator-prey interactions in tiny species such as mites, which include important agricultural pests and their predators.

利用分子技术开展肠道内容物分析（gut content analysis），可在其他研究方法难以奏效的场景中阐明捕食者-猎物（predator-prey）关系，例如螨类这类微型物种间的营养互作——而螨类本身包含重要农业害虫及其天敌。针对西班牙柑橘园中的螨类群落，我们设计了物种特异性引物（species-specific primers）：该群落涵盖2种植食性螨类——隶属于叶螨科（Tetranychidae）的二斑叶螨（Tetranychus urticae）与柑橘全爪螨（Panonychus citri），以及6种隶属于植绥螨科（Phytoseiidae）的捕食性螨类，这类捕食螨被视为上述植食性螨的核心生物防治因子。我们将上述引物成功应用于单一多重聚合酶链式反应（multiplex PCR）体系，以此检测取食这两种猎物的捕食者类群。本研究估算了猎物DNA随时间的检出成功率半衰期（DS50，detectability success over time），该指标因捕食者-猎物组合不同存在差异，取值范围为0.2至18小时。我们进一步利用这些数值对野外采集样本中的猎物检出结果进行加权校正，以厘清两种优势捕食者——斯氏真绥螨（Euseius stipulatus）与智利小植绥螨（Phytoseiulus persimilis）所扮演的捕食角色。斯氏真绥螨的校正捕食值显著高于智利小植绥螨。然而，由于这1.5倍的差异远小于二者种群丰度间7倍的差值，因此本研究判定智利小植绥螨是该系统中捕食效率最优的捕食者：其取食叶螨科物种的频率几乎是斯氏真绥螨的5倍。本研究结果证实，分子工具可有效解析这类微型物种间的捕食者-猎物互作关系。