Understanding animal foraging ecology requires large sample sizes spanning broad environmental and temporal gradients. For pollinators, this has been hampered by the laborious nature of morphologically identifying pollen. Identifying pollen from urban environments is particularly difficult due to the presence of diverse ornamental species associated with consumer horticulture. Metagenetic pollen analysis represents a potential solution to this issue. Building upon prior laboratory and bioinformatic methods, we applied quantitative multilocus metabarcoding to characterize the foraging ecology of honeybee colonies situated in urban, suburban, mixed suburban–agricultural and rural agricultural sites in central Ohio, USA. In cross‐validating a subset of our metabarcoding results using microscopic palynology, we find strong concordance between the molecular and microscopic methods. Our results suggest that forage from the agricultural site exhibited decreased taxonomic diversity and temporal turnover relative to the urban and suburban sites, though the generalization of this observation will require replication across additional sites and cities. Our work demonstrates the power of honeybees as environmental samplers of floral community composition at large spatial scales, aiding in the distinction of taxa characteristically associated with urban or agricultural land use from those distributed ubiquitously across the sampled landscapes. Observed patterns of high forage diversity and compositional turnover in our more urban sites are likely reflective of the fine‐grain heterogeneity and high beta diversity of urban floral landscapes at the scale of honeybee foraging. This provides guidance for future studies investigating how relationships between urbanization and measures of pollinator health are mediated by variation in floral resource dynamics across landscapes.

中文翻译：

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植物元条形码技术在城市-农业梯度上识别蜜蜂花粉多样性的应用

了解动物觅食的生态需要跨较大的环境和时间梯度的大量样本。对于授粉者，这在形态上鉴定花粉方面费力。由于存在与消费者园艺相关的多种观赏物种，因此很难从城市环境中鉴定花粉。遗传学的花粉分析代表了该问题的潜在解决方案。在先前实验室和生物信息学方法的基础上，我们应用定量多位元元条形码来表征位于美国俄亥俄州中部城市，郊区，郊区-农业和农村混合农业地区的蜜蜂群落的觅食生态。在使用显微镜孢粉学交叉验证我们的元条形码结果的子集时，我们发现分子方法和微观方法之间有着高度的一致性。我们的结果表明，相对于城市和郊区，来自农业用地的草料表现出较低的分类学多样性和暂时性周转率，尽管这种观察的普遍性要求在其他地点和城市之间进行复制。我们的工作证明了蜜蜂在大空间尺度上作为花卉群落组成的环境采样器的力量，有助于区分与城市或农业土地利用相关的分类单元与在整个采样景观中普遍分布的分类单元。在我们更多的城市站点中观察到的高牧草多样性和成分更新模式，可能反映了蜜蜂觅食规模下城市花卉景观的细粒度异质性和高β多样性。这为将来的研究提供了指导，这些研究调查了城市化与传粉媒介健康状况之间的关系是如何通过跨景观的花卉资源动态变化来调节的。