Natures wonders: review of ant bridge algorithm (Introduction)

by David Turell , Wednesday, December 01, 2021, 14:44 (877 days ago) @ David Turell
edited by David Turell, Wednesday, December 01, 2021, 14:59

Individual ant simple response is the key:

https://www.quantamagazine.org/the-simple-algorithm-that-ants-use-to-build-bridges-2018...

"...army ants manage this coordination with no leader and with minimal cognitive resources. An individual army ant is practically blind and has a minuscule brain that couldn’t begin to fathom their elaborate collective movement. “There is no leader, no architect ant saying ‘we need to build here,’” said Simon Garnier, director of the Swarm Lab at the New Jersey Institute of Technology and co-author of a new study that predicts when an army ant colony will decide to build a bridge.

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"To see how this unfolds, take the perspective of an ant on the march. When it comes to a gap in its path, it slows down. The rest of the colony, still barreling along at 12 centimeters per second, comes trampling over its back. At this point, two simple rules kick in.

"The first tells the ant that when it feels other ants walking on its back, it should freeze. “As long as someone walks over you, you stay put,” Garnier said.

"This same process repeats in the other ants: They step over the first ant, but — uh-oh — the gap is still there, so the next ant in line slows, gets trampled and freezes in place. In this way, the ants build a bridge long enough to span whatever gap is in front of them. The trailing ants in the colony then walk over it.

***

"Except, of course, individual ants have no idea how many of their colony-mates are holding fast over a gap. And this is where the second rule kicks in. As individual ants run the “bridging” algorithm, they have a sensitivity to being stampeded. When traffic over their backs is above a certain level, they hold in place, but when it dips below some threshold — perhaps because too many other ants are now occupied in bridge-building themselves — the ant unfreezes and rejoins the march."

Comment: Support of simple insect algorithms. Note I presented ant bridges previously:

Wednesday, November 25, 2015, 02:23