Several years ago I had a house with a garage in which there were a lot of mice. I set out glue traps for them. One morning, I found something kind of amazing. A lizard had been caught in the trap sometime during the evening, and some ants had come to take it (unfortunately piece by piece of course) back to their anthill. The amazing part is: They had built a bridge over the glue using grains of sand. The nearest place they could have found any dirt was several yards away, past the street. There were hundreds of dead ants to be found in the trap itself, trapped in the glue, so its not as though the ants knew all along that they ought to build a bridge. But somehow, they seemed to figure it out–“We’re dying here, what we need, is to go get dirt from way over there, and bring it here, and make a bridge.”
That’s the story.
He doesn’t think that last part is what individual ants were thinking, of course, but what he does think is that this is a case of mentality being expressed where we would not intuitively think there can be any subjectivity or mentality–namely, at the level of the ant colony rather than any individual ant. He thinks the colony, through trial and error, figured out a way to solve a problem, and did so in a way not predictable by any “functional” analysis of mentality.
Well, philosophy aside, the story itself seems amazing to me. But do ants have an instinct for bridge building or something?
I know some ants (I think none I would be familiar with here in the states) build bridges out of themselves sometimes. Could this behavior be related to that behavior?
If the colony was actually “thinking,” why not build a bridge of dead ant bodies? Also, how would the colony determine that sand would negate the glue? My WAG would be the much simpler explanation that the ants who died tracked in sand that built (or appeared to build) the bridge. Or maybe the big-shot professor’s wife played a trick on him and is still laughing about it to this day.
Now - I’m not saying it didn’t happen in the way your professor said - but I’m fairly (and I think rationally) skeptical.
Well, that was just to give an explanation as to why he told the story–as an illustration of what he believes constitutes mentality. In light of that, I can answer on his behalf by explaining that he would not say that thinking entails thinking of the best possible solution. Anyway, the dead ants were stuck to the glue.
It seems implausible to me to think that randomly tracked in dirt would form something one could fairly describe as a bridge.
Also, why “big-shot”?
I do wonder how accurately the scene has been described. Thats part of why I’m asking after precedents.
My point being - it would be much simpler for each individual ant to figure out it could walk across dead ants. That explanation would seem to me to be more like the sort of bottom-up thinking that most people ascribe to colony “thought.” At least as far as I understand it. Using dirt from several yards away seems more akin to the sort of problem-solving top-down thought we attribute to higher-functioning animals (hope that makes sense).
Actually I agree - but IMHO it’s more likely than the ants using dirt from a distant source to create a bridge over a glue trap. That’s why I mentioned it as a possible alternative explanation.
A joke. Pure and simple.
Like you, I’m aware of some ant bridge-building behavior. Just never over a glue trap. I was just weighing in that my BS-o-Meter went off - as in, maybe your professor wanted to see a perfect example of colony thinking and he found it. But YMMV.
I think this is the hive mind manifestation of the colony. The ants keep coming and acting like stupid ants. Sometimes carrying shit in the wrong direction, sometimes tracking in dirt, whatever it is dumb ants do. Ants also carry away their dead sometimes. The hive “figured out” how to build a bridge when the bridge was built and most who perished carried it away. Next time they want a lizard, same thing will happen, and a bridge will be built. Ants don’t remember crap about bridges or lizards (most likely), and the hive “remembers” it only in the sense that the hives that can’t do this might starve and die out. To me this is a form of intelligence (much like the human immune system is a form of intelligence).
There is certainly precedent for ants to use the “over my dead body” system for negotiating problematic situations. For instance, the Imported Fire Ant (Solenopsis invicta) will respond to flooding by forming a ball of ants containing all members of the colony, plus the queen and as many larvae as the workers can carry. The ball floats. Some ants under water may drown. Others will migrate toward the upper levels, sending somebody else under water. The process continues until the ball eventually encounters something solid, like a tree trunk or a tuft of grass. The net effect is survival of the colony. After the '04 and '05 hurricanes here (southern Florida) we were forced to do quite a lot of wading. The unaware among us learned swiftly to watch for those baseball sized reddish masses floating nearby. Touching one resulted in your tender flesh being immediately covered with as many as tens of thousands of biting and stinging ants.
But the idea of tracking sand along by accident is absurd. Ants are clean little critters that groom themselves all - well, not “day” but “throughout their active period”. And a grain of sand relative to an ant is like a tennis ball (fine clay) to a basketball (builder’s sand) to a human. There is zero chance of such an object or objects being “tracked along” accidentally.
This of course begs the question of deliberate action, or fictional story.
Looking at the dictionary, I find “antecedents” appears appropriate. But I meant to ask, in so many words, whether the behavior I describe is “unprecedented” or not. I have always heard “unprecedented” used to mean “lacking any previous examples” or something like that. So I took it that a “precedent” is something like “a previous example,” especially one that helps explain a present example. And that, too, is listed as a definition of “precedent” in the dictionary.
It’s not as exotic as all that. At a landscape seminar, I asked a Purdue University tree expert about trees I had seen as a kid, with a band of sticky goo around the trunk. “Is it some kind of bug-killer stuff, and does it work?” I asked.
He explained that the goo was called Tanglefoot for insects. It’s an alarmingly sticky treatment you apply in a band around the trunk to keep bugs from climbing any higher up the tree. It does work. However, ants, who climb up in large numbers with their herd of young aphids, will build a bridge of dead ants across the Tanglefoot. So, you have to check the goop every few days to destroy the ant bridges.
I don’t know the species names, but these are ordinary backyard ants.
When I was a kid we had a brick driveway. One day I found a trail of ants crawling across it: crossing the surface of a brick, down into a mortar trench, up onto the next brick surface and so on. The line between the grass and the half of a lizard (courtesy of my cat, who diligently ate only the rear half of every lizard caught and left the other half for whomever wanted it, presumably us) was your ordinary sort of ‘this is the straightest line I can make with my tiny ant nervous sytem’ thing.
So being a kid I stomped on them, and some died and the rest scattered. The neat thing was when I came back an hour later, they had redone the scent trail so that it was now woven along through the mortar trenches, and kept the ants off the brick surfaces. I couldn’t have stomped them even if I wanted to. Whatever ant had laid the second trail specifically set a new path that was a) non-obvious, b) was longer than the prior one and c) gave protection from a prior method of attack. And the ants were following it without deviation, scurrying along the trenches like WW1 infantry on the front.
It’s not as neat as building a bridge out of sand but as far as I could tell it was a remarkably fast and clever response to a threat while continuing the pursuit of an original objective.
The first thing I can think of is that the scent of squashed ant is something that ants would do well to avoid. They may not have crossed the area where the previous ants were stomped.
I believe it was on the SDMB, a thread about ants getting into electric relays, for example, air conditioners and water pumps. There would be hundreds of dead ants the prevented the relay contacts from closing. Ants supposedly emit an odor when they die that cries, “Come and help!” to other ants, and the dead bodies pile up. The corpses stop the switch or form a bridge.
I had this happen to me this past summer with my HVAC unit, but it was a dead spider that died when squished by the contactors that close to deliver current to the compressor. I had no AC for several days in 90 plus degree heat in my house.
