Data from: Application of ITS2 metabarcoding to determine the provenance of pollen collected by honey bees in an agroecosystem

Premise of the study: Melissopalynology, the identification of bee-collected pollen, provides insight into the flowers exploited by foraging bees. Information provided by melissopalynology could guide floral enrichment efforts aimed at supporting pollinators, but it has rarely been used because traditional methods of pollen identification are laborious and require expert knowledge. We approach melissopalynology in a novel way, employing a molecular method to study the pollen foraging of honey bees (Apis mellifera) in a landscape dominated by field crops, and compare these results to those obtained by microscopic melissopalynology. Methods: Pollen was collected from honey bee colonies in Madison County, Ohio, USA, during a two-week period in mid-spring and identified using microscopic methods and ITS2 metabarcoding. Results: Metabarcoding identified 19 plant families and exhibited sensitivity for identifying the taxa present in large and diverse pollen samples relative to microscopy, which identified eight families. The bulk of pollen collected by honey bees was from trees (Sapindaceae, Oleaceae, and Rosaceae), although dandelion (Taraxacum officinale) and mustard (Brassicaceae) pollen were also abundant. Discussion: For quantitative analysis of pollen, using both metabarcoding and microscopic identification is superior to either individual method. For qualitative analysis, ITS2 metabarcoding is superior, providing heightened sensitivity and genus-level resolution.研究背景：蜜粉孢粉学（Melissopalynology）即针对蜜蜂采集花粉的鉴定工作，可为探究觅食蜂所利用的花卉资源提供重要参考。该技术可用于指导辅助传粉昆虫的花卉增补种植计划，但由于传统花粉鉴定方法耗时费力且需要专业知识储备，其实际应用十分有限。本研究采用全新的分子检测方法，针对大田作物主导的农田景观中的西方蜜蜂（Apis mellifera）花粉觅食行为展开研究，并将该方法的结果与传统显微蜜粉孢粉学方法所得结果进行对比。 研究方法：花粉样本采集自美国俄亥俄州麦迪逊县的西方蜜蜂蜂群，采集工作于仲春时节的两周内完成，分别采用显微鉴定法与ITS2元条形码（ITS2 metabarcoding）技术进行物种鉴定。 研究结果：元条形码技术共鉴定出19个植物科，相较于仅鉴定出8个植物科的显微鉴定法，其对大型且物种多样的花粉样本中的类群具有更高的识别灵敏度。西方蜜蜂采集的花粉主要来自乔木类植物（无患子科、木犀科与蔷薇科），不过蒲公英（Taraxacum officinale）与十字花科（Brassicaceae）的花粉占比也较为丰富。 讨论：在花粉定量分析中，联合使用元条形码技术与显微鉴定法的效果优于单独使用任一方法；而在花粉定性分析中，ITS2元条形码技术更具优势，可提供更高的识别灵敏度与属级分类分辨率。