The mutualism between bees and angiosperms are amongst the most fascinating examples of mutualism. Originated in the Cretaceous about 120 Ma, pollination by bees was potentially one of the most important drivers of the extraordinary diversity of species, forms and habitat occupied by angiosperms. Bees are completely dependent on plants to feed adults and larvae, and in many cases to construct nests, sleep and reproduce, therefore explaining the huge importance of angiosperms to this animal group evolution. Studying the evolution of this mutualism, I aim to understand time and place of origin of specific relationships between bees and plants and the scenario of its evolution. Moreover I am trying to explain the astonishing diversity of specialization in morphology, behaviour and geographical distribution involved in the pollination by bees. My research also provide bases to the preservation of this endangered, economically and ecologically extremely important ecosystem service.