Honeybee microbiome is stabilized in the presence of propolis

Honey bees have developed many unique mechanisms to help ensure the proper maintenance of homeostasis within the hive. One specific method includes the collection of antimicrobial plant resins and wax to form propolis, which is deposited throughout the hive. Propolis is believed to play a significant role in reducing disease load in the colony due to its antimicrobial and antiseptic properties. However, little is known on how propolis may be interacting with the commensal bacteria of the hive and if propolis alters the microbial community structure. In this study, we demonstrate that propolis appears to maintain a stable microbial community composition and reduce the overall diversity of the total honey bee microbiome. Several key members of the honey bee gut microbiota were significantly altered in the absence of propolis suggesting that it may play an important role in maintaining favorable levels of commensal bacteria. Overall, these findings demonstrate that propolis may help to maintain honey bee colony microbial health by limiting changes to the overall microbial community.