Analysis of the meiofaunal food web is hampered because few prey have features that persist long enough in a predator's digestive tract to allow identification to species. Hence, at least for platyhelminth predators, direct observations of prey preference are almost nonexistent, and where they occur, prey identification is often limited to phylum. Studies using an in vitro approach are rare because they are extremely time-consuming and are subject to the criticism that predators removed from their natural environment may exhibit altered behaviors. Although PCR-based approaches have achieved wide application in food-web analysis, their application to meiofaunal flatworms suffers from a number of limitations. Most importantly, the microscopic size of both the predator and prey does not allow for removal of prey material from the digestive tract of the predator, and thus the challenge is to amplify prey sequences in the presence of large quantities of predator sequence. Here, we report on the successful use of prey-taxon-specific primers in diagnostic PCR to identify, to species level, specific prey items of 13 species of meiofaunal flatworms. Extension of this method will allow, for the first time, the development of a species-level understanding of trophic interactions among the meiofauna.

中文翻译：

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诊断 PCR 可用于阐明小型动物的饮食和营养关系

小型动物食物网的分析受到阻碍，因为很少有猎物具有在捕食者的消化道中持续足够长的时间以识别物种的特征。因此，至少对于扁形动物捕食者来说，对猎物偏好的直接观察几乎不存在，而且在它们发生的地方，猎物识别通常仅限于门。使用体外方法的研究很少见，因为它们非常耗时，并且受到批评，即从自然环境中移除的捕食者可能会表现出改变的行为。尽管基于 PCR 的方法已在食物网分析中得到广泛应用，但它们在小型动物扁虫中的应用受到许多限制。最重要的是，捕食者和猎物的微观尺寸不允许从捕食者的消化道中去除猎物物质，因此挑战是在大量捕食者序列存在的情况下放大猎物序列。在这里，我们报告了在诊断 PCR 中成功使用猎物分类单元特异性引物，以在物种水平上识别 13 种小型动物扁虫的特定猎物。这种方法的扩展将首次实现对小型动物之间营养相互作用的物种级理解。13 种小型动物扁虫的特定猎物。这种方法的扩展将首次实现对小型动物之间营养相互作用的物种级理解。13 种小型动物扁虫的特定猎物。这种方法的扩展将首次允许对小型动物之间的营养相互作用进行物种级别的理解。