In the past decade, it has become clear that omnivory, feeding on more than one trophic level, is important in natural and agricultural systems. Large mammalian herbivores (LMH) frequently encounter plant-dwelling arthropods (PDA) on their food plants. Yet, ingestion of PDA by LMH is only rarely addressed and the extent of this direct trophic interaction, especially at the PDA community level, remains unknown. Using a DNA-metabarcoding analysis on feces of free-ranging cattle from a replicated field experiment of heavily and moderately grazed paddocks, we reveal that feeding cattle (incidentally) ingest an entire food chain of PDA including herbivores, predators and parasites. Overall, 25 families of insects and four families of arachnids were ingested, a pattern that varied over the season, but not with grazing intensity. We identified the functional groups of PDA vulnerable to ingestion, such as sessile species and immature life stages. Most of the fecal samples (76%) contained sequences belonging to PDA, indicating that direct interactions are frequent. This study highlights the complex trophic connections between LMH and PDA. It may even be appropriate to consider LMH as omnivorous enemies of PDA.

中文翻译：

---

通过 DNA 元条形码揭示大型哺乳动物食草动物和植物节肢动物之间的神秘相互作用

在过去的十年中，很明显，杂食性，以不止一个营养级为食，在自然和农业系统中很重要。大型哺乳动物食草动物 (LMH) 经常在其食用植物上遇到植物性节肢动物 (PDA)。然而，LMH 摄入 PDA 很少得到解决，这种直接营养相互作用的程度，特别是在 PDA 社区层面，仍然未知。通过对来自重度和中度放牧围场的重复田间实验的自由放养牛的粪便进行 DNA 元条形码分析，我们发现饲养牛（顺便提一下）摄入了 PDA 的整个食物链，包括食草动物、捕食者和寄生虫。总体而言，摄入了 25 个昆虫科和 4 个蛛形纲动物科，这种模式随季节而变化，但不随放牧强度而变化。我们确定了 PDA 易被摄入的功能组，例如固着物种和未成熟的生命阶段。大多数粪便样本 (76%) 包含属于 PDA 的序列，表明直接相互作用是频繁的。这项研究强调了 LMH 和 PDA 之间复杂的营养联系。甚至可以将 LMH 视为 PDA 的杂食性敌人。