Ants’ sense of smell is so strong they can detect cancer


The ant oncologist is going to see you now.

Ants live in a world of smells. Some species are completely blind. Others are so dependent on the scent that those who lose track of a trail of pheromones walk in circles, until they die of exhaustion.

In fact, ants have such a keen sense of smell that researchers are now training them to detect the scent of human cancer cells.

A study published this week in the journal Proceedings of the Royal Society B: Biological Sciences highlights a keen sense of ants and highlights how one day we may use animals with pointy noses – or, in the case of ants, pointy antennae – to detect tumors quickly and at a lower cost. This is important because the earlier the cancer is detected, the better the chance of a cure.

“The results are very promising,” said Baptiste Piqueret, a postdoctoral researcher at the Max Planck Institute for Chemical Ecology in Germany, who studies animal behavior and co-authored the paper. However, he adds: “It is important to know that we are far from using them on a daily basis to detect cancer.

Extending their pair of slender sensory appendages atop their heads, insects detect and deploy chemical signals to do almost everything – find food, swarm prey, spot colony mates, protect young. This chemical communication helps ants build complex societies of queens and workers that work so in tune with smell that scientists call some colonies “superorganisms.”

For their study, Piqueret’s team grafted pieces of a human breast cancer tumor onto mice and trained 35 ants to associate the urine of tumor-bearing rodents with sugar. Placed in a petri dish, the silky ants (formica fusca) spent significantly longer near the tubes with urine from “diseased” mice compared to urine from healthy mice.

“The study was well designed and conducted,” said Federica Pirrone, an associate professor at the University of Milan who was not involved in the ant research but has conducted similar investigations of the olfactory ability of dogs.

Piqueret has been fascinated by ants ever since he played with them as a child in his parents’ garden in the French countryside. “I’ve always loved ants,” he said, “watching them, playing with them.”

The way we diagnose cancer today – by drawing blood, taking biopsies and performing colonoscopies – is often expensive and invasive. Animal behaviorists envision a world in which doctors one day harness species with heightened senses to help spot tumors quickly and cheaply.

Dogs can detect the presence of cancer in body odor, according to previous research. Mice can be trained to distinguish between healthy and tumor-bearing compatriots. Nematodes are attracted to certain organic compounds associated with cancer. Even fruit fly neurons ignite in the presence of certain cancer cells.

But ants, Piqueret suggested, may have the edge over dogs and other animals that take time to train.

During the covid confinements, he brought silky ants to his apartment outside of Paris to continue his experiments. He chose the species because it has a good memory, is easy to train, and doesn’t bite (at least not hard, says Piqueret).

Researchers need to do a lot more work before ants or other animals can help make an actual diagnosis. Scientists need to test for confounders such as diet or age, Pirrone said. Piqueret’s team plans to test the ability of ants to detect cancer markers in the urine of real patients.

“To have real confirmations, we have to wait for the next steps,” said Pirrone.

If ever ants are used in cancer screening, Piqueret wants to make one thing clear: no, they won’t need to crawl on you.

“There will be no direct contact between ants and patients,” he said. “So even if people are scared of bugs, it’s okay.”

Once he had to reassure someone familiar with his research that ants invading a picnic were not a sign of cancer.

“The ants weren’t trained,” he said. “They just want to eat sugar.”

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