Abstract:Honey bees (Apis mellifera) provide invaluable benefts for food production and maintenance of biodiversity of natural environments through pollination. They are widely spread across the world, being adapted to diferent climatic conditions. To survive the winter in cold temperate regions, honey bees developed diferent strategies including storage of honey and pollen, confnement of individuals during the winter, and an annual cycle of colony growth and reproduction. Under these conditions, winter honey bees experience physiological changes, including changes in immunity and the composition of honey bee gut microbiota. However, under tropical or subtropical climates, the life cycle can experience alterations, i.e., queens lay eggs during almost all the year and new honey bees emerge constantly. In the present study, we characterized nurses? honey bee gut microbiota in colonies under subtropical region through a year, combining qPCR, PCR-DGGE, and 16S rDNA highthroughput sequencing. We also identifed environmental variables involved in those changes. Our results showed that under the mentioned conditions, the number of bacteria is stable throughout the year. Diversity of gut microbiota is higher in spring and lower in summer and winter. Gradual changes in compositions occur between seasons: Lactobacillus spp. predominate in spring while Gilliamella apicola and Snodgrasella alvi predominate in summer and winter. Environmental variables (mainly precipitations) afected the composition of the honey bee gut microbiota. Our fndings provide new insights into the dynamics of honey bee gut microbiota and may be useful to understand the adaptation of bees to diferent environmental conditions.