Honey bees from Easter Island have a distinctive gut microbiota compared to those from continental Chile

The honey bee (Apis mellifera L.) is the predominant pollinating insect and provides economically important pollination services for agriculture. However, honey bee health is threatened by multiple stress factors, including the intensification of agriculture, associated to a decrease in pollen diversity and an increase in pesticides use. Honey bee gut microbiota plays a key role in the maintenance of bee health. It is involved in detoxification, immune response, defense against pathogens, nutrition, metabolism, among other functions. The aim of this study was to evaluate the composition and diversity of the gut microbiota of honey bees from different geographical and productive areas with different agricultural characteristics in Chile continental and insular (Easter Island). The gut bacterial communities of worker honey bees were analyzed through 16S rRNA amplicon sequencing (V3-V4 region). We found that honey bees exposed to different agricultural systems exhibit significant differences in their gut microbial communities. Honey bees from colonies placed in Rapa Nui (RP), an island with small-scale beekeeping activity, with low applications of pesticides, absence of varroa and no use of acaricides, showed a differential gut microbiota. It is characterized by a high bacterial diversity, and a higher abundance of Gilliamella spp. and Snodgrasella spp. than honey bees from colonies located on blueberry field (TAS), central coast bushland areas (SB) or grassland-livestock agricultural system (LAS) These results suggest that agricultural interventions and their intensive practices can negatively alter the honey bee gut microbial community, which may increase its vulnerability to biotic and abiotic stressors.