Phylogenetic comparison of bacteria isolated from the honey stomachs of honey bees Apis mellifera and bumble bees Bombus spp.
Tobias C. Olofsson and Alejandra Vásquez
It has recently been discovered that the honey bee Apis mellifera has a large flora of symbiotic lactic acid bacteria in its honey stomach, belonging to the genera Lactobacillus and Bifidobacterium. It appears that the flora may protect the honey bees, their larvae and their food against harmful microorganisms. Since bumble bees (Bombus spp.) are related to honey bees and have a honey stomach where they store nectar during their flight we investigated whether their honey stomachs also contain symbiotic lactic acid bacteria. Bacterial isolates cultivated from both the surface and from the honey stomachs of bumble bees were identified using 16S rRNA gene analyzes. The results showed that bumble bees also possess lactic acid bacteria in their honey stomachs but in fewer phylotypes and only belonging to the genus Lactobacillus. In contrast to honey bees, bumble bees do not produce honey or bee bread but feed their larvae directly with nectar and pollen, and their society does not survive the winter in temperate climates. It was therefore concluded that bumble bees have less need than honey bees of an extensive lactic acid bacterial flora.