Data from: Accuracy of a prey-specific DNA assay and a generic prey-immunomarking assay for detecting predation

Predator gut examinations are useful for detecting arthropod predation events. The accuracy and reproducibility of two different gut assays are tested on various predator species that consumed Chrysoperla carnea (Stephens), that was externally labelled with rabbit immunoglobulin (IgG). Each predator homogenate was examined in triplicate for prey remains by both a conventional PCR assay to detect for C. carnea DNA and a generic ELISA to detect for rabbit IgG marked prey. The ability of each method to detect predation over time was compared among predators and between assay types were determined using a novel three-dimensional contingency table approach. Both assays reliably detected prior predation (e.g., at least one of the three sub-samples yielded a positive reaction) for 6 to 12 h after feeding. However, the generic ELISA was more reproducible (e.g., all three sub-samples yielded the same outcome) than the PCR. This shows that it was important to assay the predators in triplicate by PCR to avoid a high occurrence of false negative reactions. Conversely, reproducible results from the ELISA procedure were not dependent on duplicate sub-samples. Overall, the generic immunomarking gut assay procedure proved an effective method to assess predation.捕食者肠道检测可有效检出节肢动物捕食事件。本研究以被兔免疫球蛋白（rabbit immunoglobulin, IgG）体外标记的普通草蛉（Chrysoperla carnea (Stephens)）为猎物，针对取食该猎物的多种捕食者物种，测试两种不同肠道检测方法的准确性与可重复性。研究人员对每份捕食者匀浆进行三次重复检测，分别采用常规聚合酶链式反应（polymerase chain reaction, PCR）检测普通草蛉DNA，以及通用酶联免疫吸附测定（enzyme-linked immunosorbent assay, ELISA）检测带有兔IgG标记的猎物。通过新型三维列联表（three-dimensional contingency table）方法，比较不同捕食者间各方法随时间推移的捕食检测能力，并分析两种检测方法间的差异。两种检测方法均可在捕食后6至12小时内可靠检出此前的捕食事件（即三次重复子样本中至少有一次呈阳性反应）。但通用ELISA的可重复性（即三次重复子样本结果完全一致）优于PCR。这表明，采用PCR对捕食者进行三次重复检测，对避免高比例假阴性反应至关重要。与之相反，ELISA方法获得可重复结果并不依赖重复子样本检测。总体而言，通用免疫标记肠道检测方法被证实是评估捕食行为的有效手段。