Birds in flocks make turns as a collective. Ants build, supply, and defend their burrows. How does a group make better decisions than any one of its members? Welcome to the hive mind.
The queen of an ant colony is like the queen of England. She doesn't really have any power (except in Canada). She doesn't oversee the colony or give orders. She's a part of the collective more than the organizer. An ant colony doesn't have an organizer. Despite that, it works efficiently.
The colony doesn't just pump out genetically pre-determined components. Many ants can switch to different roles during the course of their lives, depending on what the colony needs. Together, the colony has an intelligence, which single ants do not possess. Over the years, many different studies hae been done to explore this concept of collective intelligence.
Some study the mechanics of collective intelligence. For example, a Stanford researcher noticed that foraging ants would change their search patterns if they were given different-sized areas to search. Ants don't see very well, so they weren't able to see each other. Nor did any one ant ‘round up the others'. The most likely theory was that each ant had a number of different possible search patterns. If it ran into other ants too often, it would change to a wider-reaching search pattern. If it didn't run into them often enough, it would switch to a more conservative one. The result was all the searching ants, as a collective, changing their individual search behaviors in the same way after roughly the same amount of time.
Ants are also incredible at collectively finding the shortest routes through complicated systems, using luck and pheromone trails. As ants move through the world, they leave behind pheromones. The ants that follow behind them use a combination of chance, and pheromone scent to plot out their own routes. The first forays are random, but over time the most efficient routes have the most bunched-together pheromones trails, until the most efficient trails are discovered.
So far, it seems like just animals following instincts which lead them to a successful outcome – which is natural to all animals. The useful behaviors stick around. It's more than that, though. Collectively, a colony learns. Destroy it one day, and it will move and rebuild. Destroy it the next day, and it will do the same thing. Faster.
Collective intelligence is a possible hot concept. The behavior used by ants can be used by malware scanners, cleaning robots, and mapping programs. Design a machine to do a complicated thing, and it becomes a complicated problem if something goes wrong. Design it, and many of its fellows, to do simple things that, collectively, accomplish the same task, and things can go a lot more smoothly.
Until they rebel against us, that is.