Tag Archives: nestmates

How Pollution Alters Ant Scent, Leading to Attacks on Nestmates

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Harvester ants and the impact of ozone pollution

Harvester Ants and Scent Recognition

Credit: JorgeOrtiz_1976/Shutterstock

Common air pollutants like ozone and nitric oxide can alter the scent of ants, triggering aggressive behavior from nestmates who perceive them as intruders.

Ants rely on scent for social recognition, and when they encounter individuals with unfamiliar scents, they often react with aggression—biting or even killing the perceived invader. Notably, ozone—a greenhouse gas emitted from vehicle exhaust and industrial processes—can impact the chemical makeup of alkenes, compounds important to the unique scent profile of their colony.

Markus Knaden and researchers at the Max Planck Institute for Chemical Ecology in Jena, Germany, previously noted that ozone-induced changes in alkenes can disrupt insect communication, leading to phenomena such as fruit flies mating with inappropriate partners or pollinators like the tobacco moth losing interest in flowers. But how does ozone affect ant behavior?

To explore this, Knaden’s team established artificial colonies of six ant species, exposing them to glass chambers with varied ozone concentrations, mirroring summer levels recorded in Jena. Upon their return, the subjected ants faced attacks from their colony members.

“I honestly didn’t expect this outcome,” Knaden remarked. “We anticipated the ozone might alter just a small fraction—2 to 5 percent—of the overall scent blend.”

In natural settings, such aggressive behavior can hinder colony efficiency, even without any fatalities among the ants, though it is complex to design experiments that effectively measure these impacts.

Daniel Cronauer, a professor at Rockefeller University in New York, commented that the aggression observed is not surprising given the crucial role alkenes play in identifying nestmates.

Alkenes also facilitate other vital ant behaviors, including tracking via footprints and communication between larvae and adults. This study indicates that ozone exposure may lead clonal ant adults (Oseraea Billoi) to neglect their larvae, suggesting that these changes could disrupt various facets of ant life and potentially affect broader ecosystem dynamics.

“In most terrestrial ecosystems, the removal of ants would likely lead to catastrophic consequences,” Cronauer stated. Ants are pivotal for dispersing seeds, aerating soil, and fostering symbiotic relationships with other species.

With global insect populations in decline, this research adds to a growing body of evidence linking air pollution to these declines. Knaden asserts that while current ozone levels may not pose immediate dangers to humans, “we must acknowledge the unseen consequences of our actions.”

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Source: www.newscientist.com

Carpenter ants possess the ability to perform life-saving amputation surgery on injured nestmates

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Carpenter Ants (Camponotus) – Jumping spiders, a diverse genus of large ants that inhabit many forested areas around the world, are able to selectively treat the injured limbs of their nestmates by cleaning or amputating the wounds.

Injured (marked in yellow) Camponotus floridanus. His wounds are being treated by his nestmates. Image credit: Frank others., doi: 10.1016/j.cub.2024.06.021.

For animals, open wounds pose a significant risk of infection and death. To reduce these risks, many animal species apply antibacterial compounds to wounds.

In 2023, researchers discovered another ant species, Megaponera analis, uses special glands to inject antibacterial compounds into wounds, reducing the chance of infection.

Florida carpenter ant (Camponotus floridanus) and other species of the same genus Camponotus. Notably, they lack such glands and therefore appear to use only mechanical means to treat their nestmates.

Dr. Eric Frank from the University of Würzburg and his colleagues discovered that this mechanical care involves one of two pathways.

The ants either clean the wound using only their mouthparts, or clean it and then amputate the leg completely.

When choosing which route to take, Ali appears to be assessing the type of injury and tailoring the best treatment approach based on information.

The study analyzed two types of leg injuries: femur lacerations and ankle-like tibial lacerations.

All femur injuries involved a nestmate first cleaning the cut and then biting off the entire leg, in contrast to the tibia injuries, which involved only mouth cleaning.

In both cases, the intervention resulted in a significant increase in survival of ants with experimentally infected wounds.

“With femur injuries, we always end up amputating the leg, and we have about a 90 to 95 percent success rate. And with tibia injuries, where we don’t amputate, we achieve about a 75 percent survival rate,” Dr. Frank said.

“This is in contrast to the survival rates of untreated infected femoral and tibial abrasions, which are less than 40 percent and 15 percent, respectively.”

The scientists hypothesized that preferred methods of wound care may be related to the risk of infection from the wound site.

Micro-CT scans of the femur confirmed that it was mostly composed of muscle tissue, suggesting that it played a functional role in pumping blood, called hemolymph, from the leg to the trunk.

When the femur is damaged, the muscles are damaged and the ability to circulate blood that may be contaminated with bacteria is reduced.

The tibia, on the other hand, has very little musculature and little contribution to blood circulation.

“With a tibia injury, the hemolymph flow is less disrupted, allowing bacteria to enter the body more quickly, whereas a femur injury slows down the rate at which blood circulates in the leg,” Dr Frank said.

“If tibial injury would hasten infection, one might expect that amputation of the entire leg would be the most appropriate option, but in fact the opposite has been observed.”

“It turns out that the speed at which the ants can sever the legs makes a difference.”

“An amputation surgery using ants takes at least 40 minutes to complete.”

“Experiments have demonstrated that in the case of tibial injuries, the ants cannot survive unless the leg is removed soon after infection.”

“This means that the ants cannot cut their legs quickly enough to prevent the spread of harmful bacteria, so by taking their time cleaning the wound in their shins they try to reduce a potentially fatal infection,” says Dr Laurent Keller, an evolutionary biologist at the University of Lausanne.

“The fact that ants can diagnose wounds, determine whether they are infected or sterile, and then treat them accordingly over time with other individuals — the only medical system that could match that would be the human medical system.”

Given the sophisticated nature of these behaviors, the next question to ask is how these ants are able to perform such precise care.

“This is all innate behaviour; ants’ behaviour changes as individuals age, but there is little evidence of learning,” Dr Keller said.

of Investigation result Published in the journal Current Biology.

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Eric T. Frank othersIn order to combat infections in the ant community, they amputate legs depending on the injury. Current BiologyPublished online July 2, 2024; doi: 10.1016/j.cub.2024.06.021

This article is based on an original release by Cell Press.

Source: www.sci.news

Ants remove limbs of their nestmates to prevent infection

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Termites in Florida

Paul Young/Alamy

Some ants will bite off the infected limbs of their nestmates to improve their chances of survival, making them the only non-human animals documented to amputate a limb to save the life of another animal.

Ants are already known to be one of the few animals that treat the wounds of their fellow creatures.Megaponera analisFor example, bacteria can treat infections by secreting antibacterial substances that are secreted from special glands.

But not all ant species have these glands, he said. Eric Frank “We wanted to know what would happen to the ants when they couldn’t use antibiotics,” said researchers from the University of Würzburg in Germany.

If you look closely at a colony of Florida carpenter ants (Camponotus floridanus) In the lab, Frank’s colleague Danny Buffatto of the University of Lausanne in Switzerland discovered ants biting off the injured legs of their nestmates.

“I didn’t believe it at first,” says Frank, “I thought there must be something else going on. Maybe there was a threat, or maybe the ants thought they were attacking an enemy.”

Analysing video footage from the colony, the team found many more cases of amputation, none of which showed any signs of resistance, and moreover, these amputations were only performed on animals in the thigh area.

To investigate further, the team injured the femurs of 72 carpenter ants and infected them. Half of the ants had their legs amputated by the researchers, while the rest served as controls. Mortality rates of the amputated ants were 90 percent lower than those of the controls, suggesting that the treatment successfully prevented the spread of the pathogen.

In contrast, in other ants, amputations never occurred when the wounds were on the ants’ lower legs, and when the team repeated the experiment with lower-leg injuries, the amputation and control groups died at the same rate. This may be due to the ants’ physiology, Frank says. “Insects don’t have a central heart like humans do,” he says. Instead, several muscles pump blood around the body, and by using micro-CT scanning, the team found that many of these muscles are concentrated in the carpenter ants’ upper legs.

This means that amputating the upper leg would damage the muscles that pump blood, restricting blood circulation and allowing the infection to spread, whereas amputating the lower leg would not prevent the infection from spreading because it does not have these muscles.

“This discovery is remarkable and pushes the boundaries of our understanding of the behavioral immune system of social insects,” said Dr. James Traniello At Boston University in Massachusetts.

Tomer Chakkes Researchers at the University of Regensburg in Germany were surprised at how targeted the amputations were: “They don’t just do amputations for any injury, but only when it makes sense.”

“It’s unlikely that the ants understand the ultimate reasons why these cuts work; rather, it’s more likely that this is an innate behavior that they’re ‘born’ with,” he says.

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Source: www.newscientist.com