ants' return to the nest

dual light

Senior Member
KOREAN
Hello,

This is about an experiment on desert ants from "You Are Here: Why We Can Find Our Way to the Moon, but Get Lost in the Mall"

In this experiment, Wehner found that when the ants find food and return to the nest, they strike out on a direct, straight-line path for the nest. With regard to such ability, one possibility is that the nest emits some kind of signal, such as a smell, but he also found that 'smell' is not a factor for such ability, which is explained as follows:

"But using a simple but clever technique, Wehner proved that the ants were not following a scent. When foraging ants reached food sources, he picked up the ants and moved them to a new location. The ants responded to this displacement by running immediately in a direct course to where the nest would have been located if they had not been displaced. This proved that the ants were keeping track of the location of the nest by means of a continually updated estimate."

It is a little difficult for me to understand which part in this explanation is related to the proof that the ants were not following a scent.
Could I have your kind comment on this?
 
  • JamesM

    Senior Member
    Let's say that the ants were 10 feet south of the nest when they found food. When Wehner moved them (let's say 5 feet directly west of the nest) they still headed 10 feet north back to the "remembered" location of the nest relative to the food, which would be heading away from the actual position of the nest. If scent had been involved in this scenario they would have headed 5 feet east.
     

    Parla

    Member Emeritus
    English - US
    I'm not sure this is a language question, but:

    It's the third sentence, about how the ants acted. They had gone from their home (the nest) to a source of food. The question was, how would they find their way home again? Did their nest have a particular scent that they could smell? If that was so, they could find their way back to the nest even if they were picked up and moved. So the scientist did that: he picked them up and moved them. The ants didn't go back to the nest, though. Instead, they went in the direction that would have taken them back to the nest if they were still at the food source. So they weren't following any scent (which would have taken them to the nest). Instead, they "thought" (well, as much as ants think) they were going home by heading in a particular direction.
     

    Packard

    Senior Member
    USA, English
    I agree with James' explanation; I will offer another example.

    To travel from your apartment to your place of work, for example, requires that you walk 10 blocks north and six blocks west.

    Now that you have moved to a new apartment on the north side of town your new directions should be travel 15 blocks south and nine blocks east. But, out of habit you left your new apartment and traveled 10 blocks north and six blocks west, ending up a long ways from your proposed destination.

    In other words you used the same directions regardless of your starting point. So, apparently the ants used an old map instead of a new GPS unit.
     

    dual light

    Senior Member
    KOREAN
    Let's say that the ants were 10 feet south of the nest when they found food. When Wehner moved them (let's say 5 feet directly west of the nest) they still headed 10 feet north back to the "remembered" location of the nest relative to the food, which would be heading away from the actual position of the nest. If scent had been involved in this scenario they would have headed 5 feet east.
    Thanks, JamesM. I thought at first as you explained. On a second thought, however, I wondered whether the place where the nest would have been located if they had not been displaced, could be the original nest. Now I understand the place where the nest would have been located should not be interpreted as an original nest, but a fictitious place.
     
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