Motta, E. V. S. | bioRxiv Science

bioRxiv2025

A non-destructive approach to assess the gut microbiome of honey bee (Apis mellifera) queens using fecal samples

Fecal sampling is a widely used, non-invasive method for assessing gut microbiomes across various organisms. However, its suitability for studying the gut microbiome of honey bee (Apis mellifera) queens has not been tested. In this study, we evaluated whether fecal microbiomes accurately reflect gut microbiomes in honey bee queens, offering a potential non-destructive approach for microbiome research. We successfully obtained fecal and gut samples from 21 out of 26 queens. Bacterial communities were analyzed using 16S rRNA amplicon sequencing and qPCR. Our results indicate that queen fecal microbiomes closely resemble gut microbiomes, with no significant differences in alpha diversity and only minor differences in specific bacterial taxa. Beta diversity analyses revealed that within-pair microbiomes (i.e., gut vs. feces from the same queen) were significantly more similar than between-pair comparisons. Additionally, qPCR analyses revealed a strong positive correlation between bacterial abundances in fecal and gut samples, further supporting the use of feces as a proxy for gut microbiome composition. While promising, fecal collection from queens can sometimes be challenging. In our study, we were unable to collect feces from five queens, and these individuals lacked stored fecal material upon inspection of dissected guts. Nonetheless, our findings suggest that fecal sampling can be a useful, non-invasive method for studying honey bee queen microbiomes, enabling longitudinal assessments without compromising colony stability. ImportanceThe gut microbiome plays important roles in honey bee health, including protection against pathogens and stimulation of host physiological pathways. Because gut microbiome analysis involves destructive dissections, most research has focused on workers, given that colonies can have tens of thousands of individuals. This has left a significant gap in microbiome studies of other colony members, such as queens. Given that a queen is the sole reproductive female, her gut microbiome cannot be sampled without compromising colony integrity. In this study, we demonstrate that fecal sampling from honey bee queens provides a reliable, non-destructive alternative for assessing the composition of their gut microbiomes. We found that queen fecal microbiomes closely resemble their gut microbiomes in both taxonomic diversity and composition. This approach enables longitudinal monitoring of queen microbiomes without disrupting colony integrity, offering a valuable tool for honey bee research.

microbiology↗

bioRxiv2024

Glyphosate Effects on Growth and Biofilm Formation in Bee Gut Symbionts and Diverse Associated Bacteria

Biofilm formation is a common adaptation enabling bacteria to thrive in various environments and to withstand external pressures. In the context of host-microbe interactions, biofilms play vital roles in establishing microbiomes associated with animals and plants and are used by opportunistic microbes to facilitate proliferation within hosts. Investigating biofilm dynamics, composition, and responses to environmental stressors is crucial for understanding microbial community assembly and biofilm regulation in health and disease. In this study, we explore the independent gut colonization and in vitro biofilm formation abilities of core members of the honey bee (Apis mellifera) gut microbiota. Additionally, we assess the impact of glyphosate, a widely used herbicide with antimicrobial properties, and a glyphosate-based formulation on growth and biofilm formation in bee gut symbionts as well as in other biofilm-forming bacteria associated with diverse animals and plants. Our results demonstrate that several strains of core bee gut bacterial species can independently colonize the bee gut, which probably depends on their ability to form biofilms. Furthermore, glyphosate exposure has varying effects on bacterial growth and biofilm formation. These findings imply specific impacts of environmental stressors on microbial biofilms with both ecological and host health-related implications. Importance Biofilms are essential for microbial communities to establish and thrive in diverse environments. In the honey bee gut, the core microbiota member Snodgrassella alvi forms biofilms, potentially aiding the establishment of other members and promoting interactions with the host. In this study, we show that specific strains of other core members, including Bifidobacterium, Bombilactobacillus, Gilliamella, and Lactobacillus, also form biofilms. We then examine the impact of glyphosate, a widely used herbicide that disrupts the bee microbiota, on their growth and biofilm formation. Our findings demonstrate diverse effects of glyphosate on biofilm formation, ranging from inhibition to enhancement, reflecting observations in other beneficial or pathogenic bacteria associated with animals and plants. Thus, glyphosate exposure may influence bacterial growth and biofilm formation, potentially shaping microbial establishment on host surfaces and impacting health outcomes.

microbiology↗