In Ants at Work, Deborah Gordon writes:
The basic mystery about ant colonies is that there is no management. A functioning organization with no one in charge is so unlike the way humans operate as to be virtually inconceivable. There is no central control. No insect issues commands to another or instructs it to do things in a certain way. No individual is aware of what must be done to complete any colony task. Each ant scratches and prods its way through the tiny world of its immediate surroundings. Ants meet each other, separate, go about their business. Somehow, these small events create a pattern that drives the coordinated behavior of colonies.
When I interviewed her for EconTalk , we talked about how humans are actually a lot more like ants than people think.
Check out this extraordinary video  of what ants can achieve without top-down management. (HT: Harry Blanek). Don't miss it. It is beautiful and spectacular.