Amplicon-based microbiome profiling of honey bee drones and dandelions—the role in contributing to microbial diversity and carrying antimicrobial resistance

Introduction The microbiota of honey bees forms a complex community, whose composition changes throughout the life cycle and varies between castes and hives. Bee-inhabiting microorganisms can be transmitted through direct contact with nestmates, interactions with the hive environment, and while collecting food. Honey bees may act as reservoirs and disseminators of pathogenic microorganisms and antimicrobial resistance. While not involved in economically important pollination services, honey bee males are increasingly recognized as important for overall hive health. This study aimed to characterize bacterial communities associated with western honey bee ( Apis mellifera L.) drones at different developmental stages and dandelions ( Taraxacum officinale F. H. Wigg), located in the hives’ surrounding area, and to assess their role in maintaining microbial diversity and carrying antimicrobial resistance. Methods The microbial DNA was extracted from different stages of honey bee drones and dandelion flowers, and bacterial communities were revealed by Next Generation Sequencing of the PCR-amplified V3-V4 region of the 16S rRNA gene. The distribution of genes conferring resistance to aminoglycosides, β-lactams, tetracyclines, sulfonamides, and tylosins was analyzed by target-specific PCR. Results The results show that prokaryotic community structure differed significantly among sampled groups, including honey bee drones at different stages of life and dandelion flowers, although pairwise comparisons were not significant. Host-health-supporting beneficial microorganisms were detected across all developmental stages of drones, with higher diversity at the larval stage. The bacterial microbiota of dandelion flowers formed a separate cluster and contained taxa previously associated with plant-beneficial or phytopathogenic traits. Taxa shared between honey bee males and dandelion flowers included those that play a vital role in bee health or cause their diseases. The microbiota of honey bee drones and dandelions accumulate various ARGs, with the highest prevalence of genes encoding resistance to tetracycline and sulfonamide. Discussion Our research provides insights into the contribution of honey bee males to microbial diversity, highlights the importance of drones and dandelions as reservoirs for both beneficial and pathogenic bacteria, and identifies them as carriers of antimicrobial resistance genes.