It takes a lot of energy for a Bee to make wax, they consume about 8oz of honey to create 1oz of wax.
A swarm of Bees can be encouraged to cover objects with wax by the use of pheromones. This sculpture was created by trapping a swarm of Bees in a glass box with a wax covered human form on which they started to draw out comb. The artist had coloured wax already on the form, the Bees drew it out with their own wax to create this amazing work of art.
Here are the Bees building it:
Here is the Artist explaining his work:
He has done quite a few pieces with Bees in this way.
Further Reading:
http://www.tomaslibertiny.com/?works=sculptures
http://beesinart.com/