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

Honey bee queens are remarkable insects that can live up to 8 years compared to worker bees' mere 6 weeks. Understanding why queens live so long and remain productive is crucial because queen failure is a leading cause of colony loss in beekeeping operations. In this study, we discovered that healthy, productive queens have higher levels of a beneficial gut bacteria called Commensalibacter in their digestive system compared to underperforming queens. Using metagenomics and transcriptomics, we found that queens with more of this bacteria showed patterns of gene activity associated with youth and stress resistance, even in some older queens. This finding provides new insights into what makes a good queen bee. Understanding the relationship between gut bacteria and queen health may ultimately lead to improved methods for producing and selecting high-quality queens, which is essential for beekeeping industry. We discovered that the gut bacteria Commensalibacter melissae is more abundant in young queens compared to old queens, and identified over 1,400 genes whose expression levels correlate with C. melissae abundance. This represents a stronger association than age alone, which affected only 719 genes. Queens with higher levels of this bacteria showed enhanced expression of genes involved in stress resistance, protein maintenance, and longevity-related pathways.