Bees are flying insects closely related to wasps and ants, and are known for their role in pollonation and for producing honey and beeswax.  There are nearly 20,000 known species of bees in seven to nine recognized families, though many are underscribed and the actual number is probably higher. They are found on every continent except Antarctica, in every habitat on the planet that contains insect-pollinated flowering plants

Bees are adapted for feeding on Nectar and pollen.  the former primarily as an energy source and the latter primarily for protein and other nutrients. Most pollen is used as food for larvae.

Some pollinator insect facts
Britain has 25 species of bumblebees, of which about 11 commonly visit garden flowers.
A honeybee hive can contain up to about 60,000 bees in mid summer and they can convert the nectar they collect into over 100 pounds of honey.
There are about 260 species of solitary bee in Britain.