洞察景观环境影响蜜蜂之新视角: 肠道微生物

作为生态服务提供者的传粉蜜蜂与景观生态息息相关, 而以农田为主的景观组成显著降低了传粉蜜蜂的多样性。目前调查研究显示, 农田的扩张与蜜蜂多样性下降相关, 且农药残留对蜜蜂损害严重。景观中的开花植物决定了蜜蜂的食物(营养)组成, 其中花粉蛋白含量与蜜蜂的生长发育紧密相关。尽管研究已证实景观环境会显著影响蜜蜂蜂群的发展和个体的生长繁殖能力, 但未来还需要加强景观组成变化直接作用于蜜蜂的机制研究。另一方面, 大量研究表明蜜蜂肠道共生菌是影响宿主健康的重要因素: 可促进宿主吸收营养和抵抗病原菌。作为传粉者, 蜜蜂接触到的主要外部环境——花粉和花蜜都含有特殊的微生物, 很多研究暗示花源微生物是蜜蜂肠道菌来源之一。研究表明景观环境相关的食物(营养)、农药残留以及环境微生物都会显著影响肠道微生物。现有少量的研究证明不同景观的蜜蜂肠道微生物有差异, 景观环境可能通过作用于蜜蜂肠道微生物进而影响蜜蜂健康。然而不同景观环境中的微生物, 尤其是花源微生物和蜜蜂肠道菌之间的关联有待证明。景观对蜜蜂肠道微生物的影响值得研究, 希望可以从肠道菌的视角鉴别对蜜蜂友好的景观环境, 进而指导土地合理利用和蜜蜂保护。

A new perspective on landscape impact in bee populations: Considering the bee gut microbiome

Pollinator bees are providers of an important ecosystem service, and their survival relies completely on the landscape. Now with the landscape dominated by agriculture, bee diversity has been significantly reduced. Studies suggest that bee populations decline as agricultural land-use increases due to increased exposure to detrimental pesticides. Further, the protein content of pollen is highly important for the growth and development of a bee, and different landscapes provide distinct sources of nutrition. Although many studies have demonstrated the apparent impacts of landscape change on the population dynamics and individual survival of the bees, the underpinning mechanisms remain largely unknown. On the other hand, an increasing body of literature has shown that bee gut symbionts are of great importance to the health of the host bees in absorbing nutrients and resisting pathogens. When foraging, pollinator bees are exposed to particular microbes from pollen and nectar which have been suggested to be a source of some bee gut symbionts and could be either probiotics or pathogens. Together with landscape-related nutrition and pesticides, environmental microbes have been reported to affect bee microbiomes significantly. A number of pilot studies suggest that landscape change could affect bee microbiota, thereby influencing host health. An important linkage, however, is missing between environmental microbiota, especially those associated with the flowers, and that of the bee gut in a changing habitat. It is worth exploring how gut microbiomes respond to landscape changes. This will hopefully help us identify landscape types that are friendly to bees, so proper land-use can be implemented to protect the bees.