# Honey bee (Apis mellifera) queen quality: host-microbial transcriptomes exploring the influence of age and hindgut symbiont Commensalibacter melissae

## TL;DR

This study explores how gut microbes and age affect honey bee queen quality by analyzing gene expression and microbial composition.

## Contribution

The study identifies specific gene expression patterns linked to the gut symbiont Commensalibacter melissae in honey bee queens.

## Key findings

- Commensalibacter melissae abundance is higher in young queens compared to old queens.
- High C. melissae abundance is associated with genes related to stress response, protein homeostasis, and longevity.
- Gene expression differences linked to C. melissae are twice as numerous as those linked to age alone.

## Abstract

Understanding the biological mechanisms underlying extreme lifespan variation within species remains a fundamental challenge in aging research. Here, we investigated the role of gut microbiota and age in honey bee (Apis mellifera) queens combining 16S rRNA gene sequencing and transcriptomics. Analysis of 40 queen hindguts revealed that Commensalibacter melissae (Alpha 2.1) relative abundance was significantly higher in young queens compared to old queens. Using queens with the highest and lowest C. melissae relative abundance, RNA sequencing identified 1451 differentially expressed genes associated with C. melissae abundance, twice the number associated with age alone (719 genes). Queens with high C. melissae abundance showed distinct transcriptional profiles related to stress response, protein homeostasis, and longevity-regulating pathways, particularly genes involved in oxidative stress response and cellular maintenance. Our analysis revealed complex relationships between age, C. melissae abundance, and gene expression patterns, suggesting that multiple interacting factors contribute to queen quality. These findings contribute to our understanding of host-microbe interactions in honey bee queens and highlight the intricate relationship between gut microbiota composition and host physiology in honey bees.

The online version contains supplementary material available at 10.1186/s42523-025-00408-w.