Richardson Rodney T, Eaton Tyler D, Lin Chia-Hua, Cherry Garrett, Johnson Reed M, Sponsler Douglas B
Appalachian Laboratory, University of Maryland Center for Environmental Science, Frostburg, MD, USA.
Department of Entomology, Ohio State University, Wooster, OH, USA.
Mol Ecol. 2021 Jan;30(1):310-323. doi: 10.1111/mec.15704. Epub 2020 Nov 10.
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.
了解动物觅食生态学需要跨越广泛环境和时间梯度的大样本量。对于传粉者而言，这一过程因从形态上鉴定花粉的繁琐性质而受到阻碍。由于城市环境中存在与消费园艺相关的多种观赏物种，鉴定城市环境中的花粉尤其困难。宏基因花粉分析是解决这一问题的潜在方法。在先前的实验室和生物信息学方法的基础上，我们应用定量多基因座元条形码技术来描述位于美国俄亥俄州中部城市、郊区、城郊混合农业和农村农业地点的蜂群的觅食生态学。通过使用显微镜孢粉学对我们的元条形码结果的一个子集进行交叉验证，我们发现分子方法和显微镜方法之间有很强的一致性。我们的结果表明，与城市和郊区地点相比，农业地点的觅食分类多样性和时间周转率有所下降，不过要将这一观察结果推广还需要在更多地点和城市进行重复研究。我们的工作证明了蜜蜂作为大空间尺度上花卉群落组成的环境采样器的作用，有助于区分与城市或农业土地利用特征相关的分类群和那些在整个采样景观中普遍分布的分类群。在我们更多的城市地点观察到的高觅食多样性和组成周转率模式，可能反映了蜜蜂觅食尺度上城市花卉景观的细粒度异质性和高β多样性。这为未来研究调查城市化与传粉者健康指标之间的关系如何通过景观中花卉资源动态变化来介导提供了指导。
