Environment shapes the microbiome of the Blue Orchard Bee, Osmia lignaria

Wild bees encounter and collect environmental microbes whilst foraging. While environmental context affects bee diversity, little is known about it how affects the wild bee microbiome. We used field surveys in 17 urban gardens to examine whether and how variation in local and landscape habitat features shapes the microbiome of the solitary Blue Orchard Bee, Osmia lignaria. We installed O. lignaria cocoons at each site, allowed bees to emerge and forage, then collected them. We measured local features of gardens using vegetation transects and landscape features with GIS. We found that in microbiome composition between bee individuals varied by environmental features such as natural habitat, floral resources, and bee species richness. We also found that environmental features were associated with the abundance of bacterial groups important for bee health, such as Lactobacillus. Our study highlights complex interactions between environment context, bee species diversity, and the bee-associated microbes.

野生蜜蜂在觅食过程中会接触并获取环境中的微生物。尽管环境背景会影响蜜蜂多样性，但目前学界对于环境背景如何调控野生蜜蜂的微生物组仍知之甚少。本研究在17个城市花园中开展野外调查，旨在探究局域与景观尺度的生境特征变异，是否以及如何塑造独居蓝果园蜂（Osmia lignaria）的微生物组。我们在每个样点放置O. lignaria的茧，待蜜蜂羽化、完成觅食后进行样本采集。本研究采用植被样带法量化花园的局域生境特征，并通过地理信息系统（GIS）解析景观尺度的生境特征。研究结果表明，蜜蜂个体间的微生物组组成差异受自然栖息地、花类资源、蜜蜂物种丰富度等环境特征的显著调控。此外，我们还发现环境特征与对蜜蜂健康至关重要的细菌类群（如乳酸杆菌属Lactobacillus）的丰度存在显著关联。本研究揭示了环境背景、蜜蜂物种多样性与蜜蜂共生微生物之间的复杂相互作用关系。