Abstract
The honey bee (Apis mellifera L.) is a eusocial insect widely known for its role in pollination and plant biodiversity. Diverse microorganisms, including both beneficial and pathogenic, colonize bees and play important roles in the overall hive health. Microorganisms with biocontrol properties are natural modulators of honey bee microflora. Since most studies have focused on the characterization of worker bee-associated microbes, there is a lack of information about the drones' microbial environment. In this study, we identified cultivable yeasts from different stages of honey bee drones collected in Lithuania. Sealed larvae hosted the widest variety of yeasts. Metschnikowia species were detected across all developmental stages of drones. The assessment of functionality revealed that M. pulcherrima and M. fructicola exhibited the most pronounced biocontrol properties, accompanied by high levels of autoaggregation and hydrophobicity. Starmerella apis and M. reukaufii were distinguished by the highest autoaggregation capacity, exceeding 60%, and strong adherence to hydrocarbons. Starmerella genus yeasts demonstrated strong biofilm-forming ability. The novel information on the functionality of honey bee drone-inhabiting yeasts suggests their importance in maintaining the healthy microbiological environment of the hive. The isolated yeasts with beneficial traits may serve as candidates for future studies aimed at supporting honey bee health.