(1st Place) Effects of antibiotics on the gut microbiome of newly emerged honey bees

Honey bees are essential agricultural pollinators, making their health vitally important to food security. Beekeeping practices can have significant impacts on the wellbeing of managed bees and can influence hive persistence. The use of antibiotics to prevent and treat bacterial brood diseases, such as American and European foulbrood, has been controversial due to the potential negative impacts antibiotics may pose to adult bees. One such effect may be disruption of the normal gut microbiota. The honey bee gut microbiome plays a crucial role in bee health, performing functions like protecting against pathogen establishment and breaking down otherwise indigestible compounds. The goal of this study was to determine whether tetracycline, an antibiotic commonly used in hives, has persistent effects on the adult honey bee gut microbiome after a single exposure. In this experiment, newly emerged bees were treated with tetracycline, returned to their hive of origin, and collected one and two weeks later. Bacterial community structure in the gut was assessed using 16S rRNA gene amplicon sequencing. Bees treated with antibiotics at emergence had lower gut bacterial diversity than control nestmates, and these differences appeared more pronounced as the bees aged. These findings suggest that antibiotics may have negative impacts on adult honey bee workers, even after a single exposure during emergence.