Department of Entomology, University of Kentucky, S225 Agricultural Science Center North, Lexington KY 40546-0091, USA.
Mol Ecol Resour. 2010 Nov;10(6):1023-33. doi: 10.1111/j.1755-0998.2010.02857.x.
Molecular tools that characterize the structure of complex food webs and identify trophic connectedness in the field have become widely adopted in recent years. However, characterizing the intensity of predator-prey interactions can be prone to error. Maximizing collection success of small, fast-moving predators with vacuum suction samplers has the potential to increase the likelihood of prey DNA detection either through surface-level contamination with damaged prey or direct consumption within the sampling device. In this study, we used PCR to test the hypothesis that vacuum suction sampling will not cause an erroneous increase in the detection of 'predation', thereby incorrectly assigning trophic linkages when evaluating food web structure. We utilized general (1) Aphidoidea and (2) Collembola primers to measure the predation rates of Glenognatha foxi (Araneae: Tetragnathidae) on these prey collected by hand versus those sampled with a vacuum suction device. With both primer pairs, there was no significant increase in predators screening positive for prey DNA when sampled by vacuum suction versus those predators collected, in parallel, by hand. These results clearly validate the application of vacuum suction sampling during molecular gut-content analysis of predator-prey feeding linkages in the field. Furthermore, we found no evidence that predation was occurring inside the suction sampler because specimens collected were never observed to be feeding nor did they screen positive at greater frequencies than hand-collected individuals. Therefore, it can be concluded that the use of vacuum suction sampling devices (in this case a Modified CDC Backpack Aspirator Model 1412) is suitable for molecular gut-content analysis.
近年来，用于描述复杂食物网结构并在野外确定营养联系的分子工具已被广泛采用。然而，描述捕食者-猎物相互作用的强度可能容易出错。使用真空抽吸采样器最大限度地提高小型、快速移动的捕食者的采集成功率，有可能增加猎物 DNA 检测的可能性，要么是通过表面受损猎物的污染，要么是直接在采样装置内消耗。在这项研究中，我们使用 PCR 来检验这样一种假设，即真空抽吸采样不会导致“捕食”检测的错误增加，从而在评估食物网结构时错误地分配营养联系。我们利用通用（1）蚜虫和（2）弹尾目引物来测量 Glenognatha foxi（蛛形纲：Tetragnathidae）对这些通过手动收集和通过真空抽吸装置收集的猎物的捕食率。对于这两种引物对，当通过真空抽吸采样时，与通过手动平行收集的捕食者相比，没有显著增加对猎物 DNA 呈阳性的捕食者。这些结果清楚地验证了在野外进行分子肠道内容物分析时应用真空抽吸采样的适用性。此外，我们没有发现捕食行为发生在抽吸采样器内的证据，因为收集到的标本从未被观察到在进食，也没有比手动收集的个体更频繁地呈阳性。因此，可以得出结论，使用真空抽吸采样器（在这种情况下是改良的 CDC 背包吸气器模型 1412）适合于分子肠道内容物分析。
