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 多样性 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.