This one-minute video comes with no information about the location or the species of ant, clearly raiding a hornet’s nest for grubs. What puzzles me is how they built the damn bridge. If they started on only one side, they’d have no way to go upwards when they reached the bottom. They could start on both sides and join at the bottom, but why, if they wanted to access the nest, did they need a bridge in the first place? Why couldn’t the ants just walk directly to the nest on the ceiling? After all, they seem to cling to the ceiling, at least around the nest, pretty well.
And why did the chain go so low?
I sent the video to a friend of mine who works on ants, and he was mystified as well. Given the lack of notes about the video, he helpfully identified the ant as a New World army ant in the genus Eciton, a denizen of Mexico and South America. They’re known for their raids on wasp nests, and love to abscond with the wasp grubs (you can see that in the video).
But as for why this bridge exists, neither of us knew. So we jointly formulated a theory, which is ours. This was, perhaps, an experiment done by some naturalist, who put a piece of thread in a catenary shape from the edge to the nest to get the ants to crawl along it. But why didn’t the ants just walk directly to the nest along the ceiling? Well, the experimenter could have coated the space between the roof edge and nest with Fluon®, a slippery, Teflon-like substance that insects can’t get a grip on. They would then have to go along the preexisting thread (not visible in the video) to get to the nest. There would be no Fluon on the house side of the nest, explaining why ants are on the ceiling in that area
That’s just one hypothesis, but it’s the only one that makes sense to me. The idea that this was some kind of experiment is also supported by the fact that the video notes have no information in them, nor does the site allow comments.
As for how these ants defeat the wasps, I’m not sure, but this is their lifestyle, and they regularly raid nests like this.
If you have another theory which is yours, by all means put it below.