Bees have a worldwide distribution and are major pollinators of native flowering plants on all inhabited continents. The domestication and breeding of a number of species such as honeybees, bumblebees or stingless bees by humans has heavily impacted and manipulated their populations and distributions. Their agricultural importance as pollinators for major crops is now very significant and some are also sources for commercial honey, pollen, and wax production. Bees have also been a model species for a broad range of scientific studies for many years and the full sequencing of their genomes has now opened the way to new opportunities for functional genomics research.