Ants and their pheromones (Part 2)

© Luke Elstad / Wikimedia Commons / CC-BY-SA-3.0 / GFDL

Recently I blogged about my observation of ants’ behaviours when sprayed by a homemade ant repellent solution of vinegar and water. You can read the last blog here.

The solution has been useful for me at home, so I have more or less been diligently using it. Apparently, it works best (at repelling the ants) when you spray it around the house regularly (at the entry points such as windowsills).

Last week, I accidentally sprayed more than the usual amount of the vinegar-water solution on the table-top while the ant scouts were still randomly foraging for food.

Urgh, this time round, it was more than an invisible trap. Several of the ant scouts were kind of “pinned” down by the solution, making them immobile. I could, however, see their legs struggling to move. The rest of the ants were scurrying around. You might think that they would be heading off back to their nest, following whatever remaining scent trails (pheromones) they have released earlier. I had thought so. But no, the ants were scurrying all over the place, and I soon saw some of them heading towards those ants that were trapped in inactivity and circling the invisible “trap”.

I was curious about what the ants were trying to do, and observed a little more. It seems that they were trying to reach those ants in captivity. Wondering what they would do next if I were to remove the vinegar-water “trap”, I used a table cloth to wipe away some of the solution around those struggling trapped ants. Guess what? There seemed to be a lot of activities between these ants. There were a lot of circling (seemingly examining the situation) and a lot of ant-to-ant touch (seemingly communicating).

The next thing I observed amazed me.

One ant was trying to pull up the ant that was unable to move! And there were others trying to do the same for the others that were in similar predicaments. The actions were so clear I couldn’t have misinterpreted them. Once an ant managed to pull a trapped ant out, it carried it and scurried off at extreme high speed back to the nest. I knew that ants are strong and can carry loads many times their own weight. I was just not expecting this act, and at that very moment, I felt very touched and very bad at the same time. It was almost like a rescue mission that the ants were carrying out, and I felt bad to put them through this.

Anyway, it was only after doing some reading about pheromones recently, that I realised that there are many types of pheromones that ants can release from glands found all over their bodies. There are about ten to twenty different pheromone scents and each represents something that the entire colony would understand. Pheromones can summon a few ants to thousands of ants, depending on what is required. When an ant is squashed, it releases a kind of pheromone that warns the other ants of potential danger. Reading this, I think I understand why the ants that were not trapped knew where to go to find their friends in trouble. I am not sure if I am reading too much into this, but I am impressed by the help they rendered to their family in times of need.

It is amazing how many lessons we can learn from these little creatures!

4 Comments Add yours

  1. Andy Giger says:

    It is well possible that the ants were launching a rescue operation and carried their incapacitated sisters back to the nest. But we have to be careful not to conclude that too soon. There are too many alternative explanations that we haven’t ruled out.

    For example, they may have brought them back as food. That is actually quite plausible, as the ants recognise their nest mates by smell as well. The vinegar that disrupted the pheromone trails may well have removed or masked that sisterhood scent signal, too. And any tasty bits that an ant comes across and doesn’t recognise as a nest mate is fair game to hunt down and bring back to feed the colony.

    It’s great to observe and get inspired by the creatures around us. And you may well take away some personal lessons from that. But before we get too impressed by the apparent compassion of an ant, we need to be aware that this is based on our own interpretation.

  2. Kiat Teng says:

    Thanks Andy for highlighting the other possibilities. It did not occur to me that they might have taken them back as food, but now that you mentioned, it seems possible as well. And that will paint the picture in a totally different direction altogether!

    Unfortunately, I have no access to their nest to observe more, but again, I am not sure whether I wish to, since I may not display the same kind of reaction to a colony of ants as opposed to seeing just a small percentage of them.

    I guess I will just leave it to the surface observation for now.

  3. Andy Giger says:

    This is a good illustration of the situation many scientist are in: They have observed a phenomenon, and they may have a possible explanation, but they have no idea what other explanations could be out there, or which is the correct one (or two, or three…)

    In comes the scientific method, which is meant to (a) prevent the scientist projecting any unfounded interpretations, and (b) provide the means to check if any given explanation is plausible, based on testable evidence.

  4. Kiat Teng says:

    There should be a “like” function for comments, but anyway, thanks for the explanation!

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