The study of animal diets has benefited from the rise of high-throughput DNA sequencing applied to stomach content or faecal samples. The latter can be fresh samples used to describe recent meals or older samples, which can provide information about past feeding activities. For most invertebrates, however, it is difficult to access ‘historical’ samples, due to the small size of the animals and the absence of permanent defecation sites. Therefore, sampling must be repeated to account for seasonal variation and to capture the overall diet of a species. This study develops a method to describe the overall diet of nest-building Hymenoptera, based on a single sampling event, by analysing prey DNA from faeces accumulated in brood cells. We collected 48 nests from two species of introduced paper wasps (Polistes chinensis Fabricius and P. humilis Fabricius) in the urban and peri-urban areas of Auckland, New Zealand and selected two samples per nest. One from brood cells in the outer layer of the nest to represent the most recent diet and one from brood cells in an inner layer to represent older diet. Diet differed between species, although both fed mainly on Thysanoptera, Lepidoptera and Acariformes. Prey taxa identified to species level included both agricultural pests and native species. Prey communities consumed were significantly different between inner and outer nest samples, suggesting seasonal variation in prey availability and/or a diversification of the wasps’ diet as the colony grows. We also show for the first time potential predation of marine organisms by Polistes wasps. Our study provides field evidence that Polistes wasps feed on agricultural pests, supporting the hypothesis that some social wasp species could have a suppressing effect on agricultural pests. The proposed methodology is readily applicable to other nest-building Hymenoptera and has the potential to provide comprehensive knowledge about their diet with minimum sampling effort. Such knowledge is essential to measure the ecological impact of invasive Vespidae and support the conservation of native invertebrate biodiversity.

中文翻译：

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利用黄蜂巢研究膜翅目饮食的分子方法

动物饮食的研究受益于应用于胃内容物或粪便样品的高通量DNA测序的兴起。后者可以是用来描述最近进餐的新鲜样本，也可以是较旧的样本，可以提供有关过去喂养活动的信息。但是，对于大多数无脊椎动物而言，由于动物体型较小且没有永久排便位，因此很难获得“历史性”样本。因此，必须重复采样以说明季节性变化并捕获物种的整体饮食。这项研究开发了一种方法，可以通过分析来自巢细胞中积累的粪便的猎物DNA，来基于单个采样事件来描述筑巢膜翅目的整体饮食。我们从两种引进的黄蜂（Polistes chinensis Fabricius和P. humilis Fabricius）在新西兰奥克兰的市区和郊区，每个巢区选择了两个样本。一种来自巢外层的巢细胞代表最新的饮食，另一种来自内层的巢细胞代表较老的饮食。不同物种之间的饮食有所不同，尽管两者主要以fed翅目，鳞翅目和and形目为食。确定为物种级别的猎物分类单元包括农业害虫和本地物种。内巢和外巢样品之间所消耗的猎物群落显着不同，这表明随着菌落的增长，猎物可用性的季节性变化和/或黄蜂饮食的多样化。我们还首次展示了Polistes黄蜂对海洋生物的潜在捕食。我们的研究提供了野外证据，表明Polistes黄蜂以农业害虫为食，支持某些社会黄蜂物种可能对农业害虫具有抑制作用的假设。拟议的方法很容易适用于其他筑巢膜翅目，并有可能以最少的采样工作提供有关其饮食的全面知识。这些知识对于衡量入侵维斯皮科的生态影响和支持本地无脊椎动物生物多样性的保护至关重要。