Amazonian bees gather disintegrated wood granules, resembling sawdust, from the bottom of a rotting tree, and carry them off in their pollen baskets. This species use it for building their nests, which hang from trees, like European wasp nests.

More info on bees I encountered on a trip to the rainforest in Peru: https://oxnatbees.wordpress.com/2014/10/24/rainforest-bees/