Bacillus in the guts of honey bees (Apis mellifera; Hymenoptera: Apidae) mediate changes in amylase values

Amylase is one of three main enzymes involved in the breakdown and utilization of macromolecules. In honey bees (Apis mellifera), amylase was traditionally believed to originate only as secretion of the bee. However, other sources of amylase production, such as microbes in the guts of bees remained to be studied. In our research, we compared the differences in the amylase values in rape flower nectar and honey in the stomachs of bees. Then, culture-dependent and culture-independent (16sDNA) methods were used to isolate and identify bacteria in rape flower nectar and bee stomach honey. The dominant bacteria were added to nectar, and the amylase values of nectar with added gut microbes and nectar without added microbes were compared. Our findings indicate that the amylase value was significantly increased, which correlates with the increase in number of bacteria that occurred from nectar to honey in the stomachs of bees. The dominant bacteria in honey bee stomachs were mainly Bacillus during the flowering season of rape. Experiments confirmed that the amylase levels in nectar increased significantly when bacteria were added. These results indicate that bacteria in the foregut of bees help in the processing floral nectar into honey.