Natures wonders: desert ants navigation aides (Introduction)

by David Turell , Wednesday, July 19, 2023, 19:47 (282 days ago) @ David Turell

The ants build them:

https://www.sciencedaily.com/releases/2023/05/230531150134.htm

"'The desert ant Cataglyphis fortis stands out due its remarkable ability to successfully navigate and forage in even the harshest environments, making it an excellent subject for studying the intricacies of navigation. With an innate navigation mechanism called path integration, these ants use both a sun compass and a step counter to measure the distances they cover. In addition, they possess the ability to learn and utilize visible and olfactory cues. We believe that this extremely harsh habitat has led, during evolution, to a navigation system of unsurpassed precision," said Marilia Freire, the study's lead author, summarizing what is known so far about the amazing orientation skills of these small animals.

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"For their experiments, the researchers followed the ants with a GPS device. This allowed them to track the ants on their way to the saltpan and back home. "We observed that desert ants are capable of traveling much greater distances than previously reported. The farthest distance a single animal traveled was more than two kilometers. However, we also observed an unexpectedly high mortality rate. About 20% of foraging ants do not find their way back home after extremely long runs and died in front of our eyes, which explains the enormous selection pressure for even better orientation," says Marilia Freire.

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"In ant nests, labor is divided. Ants that go foraging are usually older and more experienced nest members, while younger ants are busy building. Therefore, there must be some kind of information flow between the two groups. The researchers do not yet know exactly how this is achieved. "One possibility would be that ants in the nest somehow notice that fewer foragers return home, and as a result, hill-building activities at the nest entrance are increased," says Marilia Freire.

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"Markus Knaden has been studying desert ants for 25 years and is still amazed by their fascinating abilities: "The animals can learn visual and olfactory cues despite their small brains. In addition, they are able to decide which information is useful for their navigation and which is not. All this was already known. However, the fact that they even build their own landmarks for orientation and only choose to invest in this work when other environmental cues are missing is quite surprising.'"

Comment: since individual ants must make decisions, and individual ants are known to react automatically in ant swarms, it is currently unknown whether these reactions are automatic or spontaneous. Both are possible.