The microbes in the gut help us to exploit our food sources and provide valuable metabolic mechanisms that we otherwise lack. Termites, for example, have a specialized set of microbes in their gut to allow them to consume houses. Bees don’t generally prefer wood in their diet, but they have their own set of microbes to help them to exploit pollen and nectar. Be they honeybees, solitary bees, bumblebees, or even wasps, they each carry specialized sets of microbes to permit exploitation of food resources. Perhaps these microbes are what help to turn nectar into honey. If you see a bee and wonder what species it is, analyze its gut flora to find out. See this article from Molecular Ecology that describes some of the bacteria living with bees.
This article was kindly suggested by Costa Georgopoulos.