Theo Thormann
It takes true dedication for a researcher to risk being gored by a boar to study an ant. But that’s Elise Nowbahari, who, at her own peril, documents ant rescue behavior.
In graduate school, Nowbahari studied ant aggression, but also became interested in ant rescue behavior when she saw it on a field trip in the south of France in one species, Cataglyphis cursor.
“I saw that when we disturbed them, sand would fall around them, and some ants would come and help free the others (that were trapped in sand),” said Nowbahari, who said the species was her favorite. She continued researching ant aggression, but could not quite forget the intriguing rescue behavior she had seen.
So when a student sought to do an internship, Nowbahari thought she would suggest the rescue behavior she had observed as an option.
But, as often happens in science, what they actually saw was less than overwhelming.
“It was very strange, and we could not understand what was happening because sometimes we saw some of what I saw in the field but others it was very difficult to reproduce it,” Nowbahari said. Unable to reproduce the rescue behavior in the lab, the disappointed student intern eventually drifted away from the project. It seemed like the rescue behavior Nowbahari had seen during her collection trips were not reproducible.
Then, when a second student sought a project a few years later, Nowbahari decided to give the rescue behavior experiment another go.
“I tried many times with this new student to see how we can reproduce the field behavior correctly,” she said. “Eventually the idea came that we could attach a piece of thread to the ants. This way we would have time to look at it and reproduce the behavior.” Their perseverance paid off, paving the way for a host of other experiments that would measure ant rescue behaviors in a variety of ant species.
Karen Hollis, another leading ant behavior researcher, soon after she was tempted with a trip to Paris, began collaborating with Nowbahari.
The two myrmecologists’ (yup, that’s what ant researchers are called) first paper together on the subject was published in PLOS One in 2009. But while Nowbahari and her students had figured out how to replicate rescue behavior in the lab, conducting field research on rescue behavior still presented some challenges.
While field research seems relaxed and benign, Hollis told Truly Curious of her experience during a study of rescue behavior in Reserva Científica Doñana in Spain.
“Wild boars are ferocious animals, and they have tusks. If you get in their way, they could bore you,” she said, perhaps tongue in cheek. “These ants that live in sand, their nests would frequently become trampled by the boar, and the sand would fall in all over them. Hence, no wonder they’re rescuing (their comrades). We had to beware of the wild boar and, on more than one occasion, we got a little too close and had to scurry away.”
Since publishing that first paper together in PLOS One, Nowbahari and Hollis have documented examples of rescue behavior in many ant species. Hollis said that one of the most fascinating things about their research has been watching how organized the ants seemed at freeing captive victims.
“More than once, some ants, after they had moved the sand away from the filter paper, would turn the filter paper over and start biting at the knot underneath.” Hollis does not believe the ants really knew what a knot was, but it was still a fascinating insight into how good these ants have gotten at rescues.
They found that within five days of emerging from the pupal cocoons, ants show rescue behavior equivalent to that of older workers that are even 20 days old. But callows – ants within two days of their emergence from cocoons – are largely immobile and appear incapable of helping another ant in distress.
Recent studies using rodents and other animals suggest that non-humans may be feel empathy. While Hollis and Nowbahari are not arguing that ants are showing empathy the way that mammals might, they both refer to the “proto-empathic behavior” being displayed by the ants.
“There are many animals that rescue one another,” Hollis pointed out. “Looking at ants you can ask why that might have occurred, and then what might be the evolutionary steps that led to more sophisticated rescue behavior.” According to her, the ants’ rescue mission incidentally benefit the colony and promote its survival, but suggests the ants’ behavior may be the beginnings of what evolved into empathy in humans.
Despite the success, the researchers still struggle to answer some questions.
Nowbahari said the team has had some difficulty finding the chemical composition of the pheromone that the trapped ants use to trigger rescue behavior in the ant rescuers.
“I tried to answer this question with (help from) two or three students,” Nowbahari said. “We tried to find out what is the exact pheromone that comes from the ants’ gland. It is much more complex than what we can see and, unfortunately, I have some answers, but not exact (ones).”
But the team is at the job. All they need to do is keep clear of irate ants – and boars.
Theo Thormann has a B.S. in environmental science and policy from the University of Maryland, College Park
This is the link to the original article (paywalled!)
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