# The Honey Bee Body Surface as a Microbial Hub: Connectivity Shaped by Monoculture vs. Polyculture Farming

## TL;DR

Honey bees' microbial communities are shaped by farming practices, with monoculture reducing diversity and polyculture supporting healthier, more connected ecosystems.

## Contribution

This study reveals how monoculture and polyculture farming influence honey bee-associated microbial networks and diversity.

## Key findings

- Monoculture farming reduces microbial diversity on honey bees, potentially harming their health.
- Polyculture farming supports diverse and interconnected microbial communities linked to honey bees.
- Honey bee body surfaces act as microbial hubs connecting environmental and hive networks.

## Abstract

Honey bees are not only important pollinators but also bioindicator species, one key factor being that their microbial communities reflect habitat quality and agricultural practices. This study explored how growing single crops (monoculture) versus multiple crops (polyculture) affects the microbial diversity and networks associated with honey bees. Researchers analyzed microbial communities from flowers, pollen, nectar, honey bees, and hives across three types of farms: a rape monoculture, a pear monoculture, and a polyculture system. We found that monoculture farming reduces microbial diversity, which can negatively affect honey bee health, while polyculture farming supports diverse and interconnected microbial communities that benefit both honey bees and the environment. These findings emphasize the need for sustainable farming practices to protect honey bee health, maintain biodiversity, and support ecological and agricultural stability.

Honey bees, as vital pollinators and essential contributors to terrestrial ecosystems, play a critical role in maintaining biodiversity and ecological stability. Beyond their role as pollinators, honey bees are increasingly recognized as bioindicators of environmental health, with their microbiomes reflecting habitat quality, agricultural practices, and broader ecological conditions. This study examines the impact of monoculture and polyculture systems on bee-associated microbiomes, focusing on microbial diversity, composition, and functional roles. Microbial communities from floral surfaces, pollen, nectar, foraging bees, hive matrices, and bioaerosols were analyzed across three agricultural plots: a rape monoculture, a pear monoculture, and a polyculture plot. Using 16S rRNA amplicon sequencing, network co-occurrence analysis, and microbial source tracking, the findings reveal that plant species and cultivation methods significantly shape microbial dynamics (Adonis = 0.67 ***). Floral microbiomes exhibit host specificity (Adonis = 0.73 ***), while the honey bee body surface functions as a microbial hub linking environmental, floral, and hive microbial networks (average degree pear: 21.86; rape: 21.96). The polyculture system improves microbial diversity due to the diversity of nectar plants, enhancing ecosystem connectivity and potentially benefiting honey bee health. These results highlight the ecological importance of optimizing agricultural practices to preserve microbial diversity, enhance honey bee health, and maintain ecological stability.