Leafcutter ants are fascinating tropical creatures that farm fungus gardens, require access to certain resources in order to survive and grow, and are constantly splitting off from the pack to form new colonies with connections to the old. Which, of course, makes them the perfect species to adapt into a version of Settlers of Catan, as entomologist M.L. Henneman has done. — Maggie
The big benefit to something like this is that it could allow scientists to easily alter the populations of social insect groups. Each colony of ants functions, in many ways, like a single organism. So what happens to that hive mind if you remove all the ants doing one particular type of task? Instead of painstakingly picking out each worker with a pair of tweezers every time you want to try this, you could create a colony in which all the workers have had magnetic paint daubed onto their abdomens. Then, you could quickly and easily collect some of them, or all of them, using a magnet. Hunting ants with a tweezer once > hunting ants with a tweezer over and over and over.
Another, possibly less legitimate, use of the paint is demonstrated by Quitmeyer in this video. (Quitmeyer, for the record, is not a social insects researcher.) Using single painted ants in a population of unpainted ants, he plays around with the way colonies remove unhealthy members of their own community. When a magnetized ant starts flopping around erratically in response to a nearby magnet, nearby ants quickly react.
As Quitmeyer says in the video, this demonstration quickly passes from science into mad science (or, at least, YouTube science).
In the video, researchers pump 10 tons of concrete down an ant hole and then slowly, carefully excavate the site to see what an ant colony looks like. The result is an intricate structure, equivalent in labor to humans building the Great Wall of China.
And then you think, "Oh, and we just pumped 10 tons of concrete down it. Oh. We're ... kind of assholes sometimes, aren't we?" Sorry ants. Sants.