"Let's carry his head around, cause that guy was acting like a nut," says Andrew Quitmeyer, who is currently "designing and implementing computer-vision based animal behavioral research and documentaries." It's a weird sentence, but seems appropriately bizarre given the experiment it's uttered during. A post on Quitmeyer's website titled "Magnetic Insect Testing" details his experiments with ants, magnets and magnetic paint, which result in some weird and unique behavior.
He explains that superorganisms like ants--defined as a collection of agents which can act in concert to produce phenomena government by the collective--are much easier to experiment on than regular organisms, since their behavior can be modified incrementally and returned to normal afterwards. Quitmeyer mixed up some non-lethal magnetic paint and dabbed it onto a couple ants with a couple ideas in mind.
For scientists, "tagging" certain small animals or insects with magnetic paint would make them much easier to retrieve for periodic study--just run a magnet over the ant colony to pick up the appropriate workers. Then there's the superorganism experiment angle--changing the behavior of certain ants to see how the others react. When Quitmeyer moved one painted ant around by sliding a magnet back and forth near it, the other ants responded to its erratic movement by biting its head. That means "stop freaking out" in ant, apparently.
Quitmeyer's video of him playing with the ants is an interesting look at their behavior. It's also creepy, thanks to Andrew's mad scientist-style voiceover. "I provide a andy's-been-programming-too-long crazy narration of the events," he writes.
Ants actually have an interesting sensitivity to magnets--a post on Scientific American last year showed that ants can learn to follow environmental clues back to their nests, including visual, vibrational, olfactory and magnetic landmarks. Normally the desert ants in the study use their own sense of "path integration," whcih Scientific American describes as "innate mental trigonometry," to get back home. But when their home was paired with an environmental landmark--like a smell or magnetic anomaly--they learned to use those cues. And when the two were separated, they relied on the smell or magnetism to guide them home and walked right past their nest.
Researchers still aren't exactly sure how ants sense the magnetic field, though:
"Despite the ants’ ability to learn an association between magnetic cues and their nests’ location, it is not clear whether enough magnetic variation exists for magnetic fields to be useful homing cues for ants under normal circumstances. In addition, the ability to pair a magnetic field with their nest’s location does not by itself indicate the presence of some sort of magnetic organ within ants. Instead, it could be that the magnetic fields created some generic sort of change in the way the ants’ neurons fired near their nest’s entrance. If this is the case, then the ants’ association of the magnet with their nest may not be due to the magnetic field, per se. As ever, more research will be required to investigate this possibility."
Ants, man. How do they work?