Floral and Foliar Source Affect the Bee Nest Microbial Community

Area of Science:

• Agricultural Science
• Microbiology
• Entomology

Background:

• Managed pollinators are crucial for global crop production.
• Foraging bees interact with diverse microbes from floral and foliar sources.
• The composition of the bee-nest microbiome is influenced by these interactions.

Purpose of the Study:

• To investigate how floral and foliar sources affect the microbiome of alfalfa leafcutting bee (Megachile rotundata) nests.
• To determine if bee-nest microbial communities are derived from environmental sources.
• To identify potential plant pathogens within bee nests.

Main Methods:

• A 2x2 factorial design exposed M. rotundata adults to varied floral and foliar sources.
• 16S rRNA gene and internal transcribed spacer (ITS) sequencing were used to analyze bacterial and fungal diversity.
• Microbial communities in bee nests were characterized.

Main Results:

• Nest microbial communities significantly differed between treatments, confirming environmental inoculation.
• Diverse bacterial and fungal communities were found, including plant and bee pathogens.
• No significant interactions were observed between bacterial and fungal communities.

Conclusions:

• Alfalfa leafcutting bees transfer plant-associated microbes, including pathogens like smut fungi and blight/wilt bacteria, into their nests.
• Bee nests can serve as reservoirs for plant pathogens across seasons.
• Further research is needed to explore bee-mediated pathogen transmission from nests to host plants.