When you come down with a cold or flu, you can choose to keep a distance from other people to spare them from a similar unusual fate – and in turn they can get away from you. According to the new study, people are not alone in their efforts to seize sick people. In the presence of infectious pathogens, modest garden ants can also change their behavior in order to keep contaminated blood flow apart from other colony members.
Ants are social creatures. They live in large groups, communicate and collaborate with each other to ensure that the colony functions properly. Because they are often in close contact, the ants are also susceptible to contagious diseases. Studies have shown that ants can sustain bird diseases through a series of hygienic mechanisms, such as the removal of garbage and the body of members of dead colonies from their nests. Scientists have doubted that insects will also affect their social behavior in order to reduce the spread of infections, but this hypothesis is difficult to prove.
"There are hundreds of individuals in the Ant colony," explains Nathalie Stroeimeit, a postdoctoral researcher at the University of Lausanne in Switzerland, who studies collective behavior in the colonies of Anthony. "So far, there was no technical methodology for measuring their interactions at the level of colonies over a longer period of time."
Fortunately, the automated tracking system developed by Swiss researchers in 2013 allowed Stroeimeit and her colleagues to take a closer look at how 22 colonies raised by laboratories behave when diseases are percolated in their environment. The team buried small 2D barcodes on the ants labor, giving each insect a unique identifier – "just like the KR code," says Stroeimeit. A camera placed above the antenna enclosure opens two images every second, and the algorithm detects and records the position of each barcode, giving researchers rich data on the movements of the ants.
For four days, the team allows the ants to flood in their cabin without a trace. As with wild colonies, some ants worked outside the nest to feed the food, while others, like the queen and "sister", who had the tendency to develop, stayed in the nest. On the fifth day, the researchers presented some, but not all, potatoes from 11 colonies to fungi Metarhizium brunneum, which is often found in the land of habitats of garden ants, and is known to make them sick. Furmans from the other 11 colonies were treated with a benign solution, which serves as a control group.
Of crucial importance, the previous studies have shown that M. brunneum Fungi need at least 24 hours to infect ants, which in turn gave researchers time to observe insects before they were really ill.
"We wanted to focus [this] a period … so that we could distinguish the active reaction of the ant from the unwanted effects of the disease or parasitic manipulation, "Stroeimeit explains.
Writing in the magazine Science, researchers find that, when the feeders returned to the enclosure, contaminated ants spent more time outside the nest, which means they had fewer contacts with the most valuable colony members: the queen, who laid all the colony eggs, and the indoor workers, who are younger from the Crusaders and therefore have more hours to contribute to the colony. (The older ants have the task of risking jobs outside the nest, because, as Stroeimeit makes it clear, "they will die anyway.")
But the essence of the research lies in the discovery that contaminated ants are not the only ones who change their behavior. Cattle that were not exposed to mushrooms also increased the time spent in the nest. The nurses inside the nest moved young ones from within and spent more time overlapping with them, which could "be seen as spatial isolation from the crusaders," says Stroeimeit.
How did the colony know that it was to take action to prevent the disease before the fungal spores had even infected certain crowns? Researchers are not sure, but the powerful odor of ants can be crucial. The ants reassure themselves around with their antennas, which constantly touch and take insects in the environment. It is perfectly possible, according to Stroeimeit, that the ant will be able to detect fungal fungi on one of its members of the colony, as easily as it could retrieve the pathogen on its own body.
Why non-contaminated potatoes have also reduced the time spent in the nest yet another interesting question. As the first contact line with their colleagues who were soon ill, they might somehow have known to stay away from the important members of the colony. But it is also possible that, by detecting pathogens on their colleagues, they simply spent more time for treating contaminated workers outside the nest. Ants produce formic acid through the glands at the top of the tusks or stomachs; They can kill fungal spores one on the other, getting formic acid in the mouth and licking the body of their pathogenic fellow.
Although researchers recorded less interaction between cruisers and indoor workers, the contact did not stop completely – which led to another interesting discovery. When using modeling simulations as fungal pathogens expanded throughout the colony in relation to changes in the social network of ants, researchers found that the likelihood of the queen and nurses received a potentially fatally burdensome fungus, but the probability of these important ants who received low loads increased se.
"It's similar to immunization or vaccination in humans," Stroeimeit explains. "These low doses do not lead to mortality, but allow ants to develop some kind of protection from later exposure to the same pathogen. [finding] it is also something that is completely new. "
On the move forward, Stroeimeit plans to explore how pathogens trigger social changes in the wild colony ants, which can be counted into hundreds of thousands; she doubts that segregation between prisoners and open workers may be more pronounced in these large groups.
Megan Frederickson, associate professor of ecology and evolutionary biology at the University of Toronto, who was not involved in the new study, called the researcher's findings "a new and exciting finding" that brought "the most up-to-date methods". She adds that similar technology can help scientists investigate whether ants also change their social networks to transfer useful microbes to each other. And Frederickson thinks "Character." [of the study] even beyond the ants. "
"I wonder," she says, "how often other social animals reorganize their networks to limit the spread of the disease."
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