Tag Archives: ant

Close-in of an ant carrying something.

Ants handle social isolation about as well as humans do — poorly

If you’re having a hard time coping with the isolation this pandemic has imposed on us, find solace in the fact that ants, too, would be just as stressed as you in this situation.

Close-in of an ant carrying something, probably a crumb of bread.
Image via Pixabay.

A new paper reports that ants react to social isolation in a similar way to humans and other social species. The most notable changes identified in ants isolated from their groups involve shifts in their social and hygiene behaviors, the team explains. Gene expression for alleles governing the immune and stress response in the brains of these ants were also downregulated, they add.

The burden of loneliness

“[These observed changes] make the immune system less efficient, a phenomenon that is also apparent in socially isolating humans — notably at present during the COVID-19 crisis,” said Professor Susanne Foitzik from Johannes Gutenberg University Mainz (JGU), lead author of the study. The study on a species of ant native to Germany has recently been published in Molecular Ecology.

I don’t think I need to remind you all of this, but humans find social isolation to be a very stressful experience. It can go as far as having a significant and negative impact on our physical health and general well-being. Loneliness, depression, and anxiety can set in quite easily in isolated individuals, they also develop addictions more easily, and their immune system (along with their overall health) takes a hit.

Still, we know much less about how social insects respond to isolation than we do about social animals, including humans. Ants are extremely social insects, living their whole lives in a dense colony and depend on their mates to survive (just like everyone else there). Their lives are so deeply steeped in the social fabric of their colony that worker ants don’t even reproduce, instead caring for the nest and queen, who does all the baby-making. This would be an unthinkable proposition for most other species on Earth.

The team worked with Temnothorax nylanderi, a species endemic to Western Europe. This species lives in cavities formed in fallen plant matter such as acorns or sticks, with colonies usually containing a few dozen workers. The researchers collected young worker ants who were involved in caring for the young from 14 colonies, keeping them in isolation for varying amounts of time. The shortest was one hour, and the longest, 28 days.

After the isolation period, these ants were released back to their colonies. The team explains that these individuals seemed to show lower interest in their adult colony mates, spent less time grooming themselves, but spent more with the brood.

“This reduction in hygienic behavior may make the ants more susceptible to parasites, but it is also a feature typical of social deprivation in other social organisms,” explained Professor Susanne Foitzik.

Gene activity was also impacted. The authors report that a constellation of genes involved in governing the immune system and stress response of these ants was “downregulated”, i.e. less active. This finding is consistent with previous literature showing a weakened immune system after isolation in other social species.

“Our study shows that ants are as affected by isolation as social mammals are and suggests a general link between social well-being, stress tolerance, and immunocompetence in social animals,” concludes Foitzik.

The paper “Social isolation causes downregulation of immune and stress response genes and behavioral changes in a social insect” has been published in the journal Molecular Ecology.

Scientists design spider- and ant-inspired metal structure that doesn’t sink

This metallic structure is so water repellent (superhydrophobic) that it can stay afloat even when it is highly punctured. The innovative design was inspired by diving bell spiders and the rafts of fire ants.

A metallic structure etched by lasers, right, floats to the top on the water’s surface in professor Chunlei Guo’s lab. Credit: University of Rochester photo / J. Adam Fenster.

Researchers at Rochester University, led by Chunlei Guo, who is a professor of optics and physics, used high-speed, femtosecond laser pulses to etch intricate micro and nanoscale patterns onto the surface of aluminum plates. These patterns trap air, making the surface superhydrophobic.

However, when the plates are immersed in water for long periods of time, they eventually start losing their water-repelling properties and sink. Luckily, nature had already found a solution.

Diving bell spiders (Argyroneta aquatic) can survive for extended periods of time underwater by trapping air in their dome-shape web, also called a diving bell. The web carries air from the surface between the spider’s super-hydrophobic legs and abdomen. Fire ants employ a similar strategy, forming a huge raft out of many individuals that can stay afloat thanks to the air trapped between the ants’ superhydrophobic bodies.

“That was a very interesting inspiration,” Guo says. As the researchers note in the paper: “The key insight is that multifaceted superhydrophobic (SH) surfaces can trap a large air volume, which points towards the possibility of using SH surfaces to create buoyant devices.”

The researchers treated two aluminum plates by etching patterns with lasers and then placed them parallel to one another, facing inward, rather than outward. The resulting structure is enclosed and free from external forces. The separation between the plates is just right such that the structure may trap air to keep it floating. Essentially, the setup creates an air-tight, waterproof compartment even when the structure is forced to submerge in water by a heavy object.

The superhydrophobic structure remains afloat even after significant structural damage.

Tests showed that even after being submerged for two months, the structure still bounced back to the surface of the water once a weight was released. When the structure was punctured multiple times, it could still float because air remained trapped in the undamaged sections. Guo says that although they used aluminum for this study, any metal could be made to float using this etching process.

According to the researchers, the technology is ready for commercial applications since the industry is already equipped with the fast scanning lasers required to do the nanoscale etching. Possible applications include unsinkable ships, highly water-resistant wearables, and electronic monitoring sensors that can survive long-duration missions in the middle of the ocean.

The findings were reported in the journal ACS Applied Materials and Interfaces.

Fastest ant in the world lives in the Sahara and it runs for dear life — at around 85 cm per second

The Saharan silver ant (Cataglyphis bombycina) is the fastest ant found so far, a new study reports — and, relative to its body size, one of the fastest animals out there.

Head view of the Saharan silver ant.
Image credits  www.AntWeb.org.

When measured in body lengths per second, this petite ant is, hands-down, one of the fastest animals we’ve found so far. At a speed of 855 millimetres (33.66 inches) per second, the Saharan silver ant moves roughly 108 times its body length per second. Cheetahs, for comparison, can only manage 16 body lengths per second, while Usain Bolt can only pull off 6.2. A human going at 108 body lengths per second would move at around 800 km (around 500 mi) per hour.

Small but fast

While birds do have a special place on the ‘fastest animals’ list, they also have the unfair advantage of being able to fly. If you only consider running speeds relative to body size, however, the ant is the third-fastest animal alive. First comes the Californian coastal mite (Paratarsotomus macropalpis) at 322 body lengths per second, and the a species of tiger beetle (Cicindela hudsoni) at 170 body lengths per second.

The ant’s incredible speed is an adaptation to its scorching home in the Sahara. While most animals there avoid going out during the day like the plague, the Saharan silver ant adapted to survive the burning sands. The ants have longer legs than their relatives to keep their bodies farther up from the sand and the heat it gives off. Their bodies also produce heat shock proteins before even leaving the nest, for maximum heat resistance. The ants are also able to track the Sun to help them navigate (so they spend as little time outside as possible), and are covered in hairs with a triangular cross-section that reflects and dissipates heat. Finally, they move really fast — also important when trying to get out of the sun.

Dorsal view of the Saharan silver ant.
Image credits  www.AntWeb.org.

Put all of these features together and the ants are able to go out in the baking desert sun for a few minutes at a time, scavenging carcasses for food.

To find out exactly how fast the ants move, biologists from the University of Ulm in Germany decided to film them using a high-speed camera. They first located a nest in the desert and attached an aluminum channel to the entrance, with a feeder at the end, to lure out the ants. In addition, the team carefully excavated a nest and brought it back to Germany, to see how the ants moved in cooler temperatures.

“After the ants have found the food – they love mealworms – they shuttle back and forth in the channel and we mounted our camera to film them from the top,” said biologist Sarah Pfeffer, first author of the study.

The team reports that the ants operate at maximum efficiency in the desert, reaching speeds of up to 855 millimeters per second. In the cooler environment of the lab, they would leisurely stroll around at 57 millimeters (2.24 inches) per second. The secret to their speed is in the gait, the team reports. The Saharan silver ant can swing its legs at speeds up to 1,300 millimetres per second and extends its stride from 4.7mm to 20.8mm as it reaches higher speeds.

At full gallop, all six of the ant’s feet hit the ground at once, and only stay there for around 7 milliseconds. The team believes this helps the ant keep its tiny ant feet cool and prevents them from sinking in the sand.

The paper “High-speed locomotion in the Saharan silver ant, Cataglyphis bombycina” has been published in the Journal of Experimental Biology.

Florida Harvester Ant.

Desert ants’ complex behavior is actually built from very simple interactions

Ant colonies don’t organize per se, but they still pull off complex behavior in harsh environments without any glitches. New research looks into how the insects manage this, offering inspiration for future robotic systems.

Florida Harvester Ant.

Florida Harvester Ant (P. badius).
Image credits Judy Gallagher / Flickr.

Researchers from Princeton have created a new mathematical model to explain how desert harvester ants coordinate efforts to gather seeds. This seemingly-simple process actually needs to be very finely-tuned: in the desert, the colony needs to carefully weigh the water expenditure of foraging against the benefit of bringing in seeds (which serve as both food and water). The model could help future research analyze how ant colonies respond to environmental changes, the team writes, and how behavioral differences among colonies affect their long-term survival and reproductive success.

Anting it

“[The study] was this beautiful marriage of the opportunity not just to collect data, but to define experiments — to use our models and our perspective to try to understand the connection between what individuals are doing and what happens at the level of the group,” said Naomi Ehrich Leonard, Princeton’s Edwin S. Wilsey Professor of Mechanical and Aerospace Engineering, and the paper’s corresponding author.

The study was borne of Professor Leonard’s expertise — she has previously analyzed the dynamics of bird flocks and fish schools to understand how large groups can operate efficiently without central control — and that of Stanford University biologist Deborah Gordon. Gordon and her team have spent the last three decades monitoring red harvester ants (Pogonomyrmex barbatus) at a field site in the New Mexico desert.

Leonard powered-up Gordon’s efforts with a computer model meant to describe how interactions between individual ants generate the complex and highly-tuned behavior seen on the colony-level. In turn, the research will help in the design of robot swarm teams for search and rescue missions or other tasks in environments we can’t reach.

All in all, the ants are an excellent example of how a group of individuals interacts and makes tradeoffs in uncertain conditions. In the dry deserts of the southwestern United States and northern Mexico, red harvester ants gather seeds for both food and water. However, unless they go about it properly, they risk losing more water than they recover from seeds — which would, eventually, lead to the colony dying of dehydration.

“The ants are able to regulate the rate at which they send out foragers with a very limited communication framework,” says Renato Pagliara Vasquez, the study’s lead author.

Vasquez explains that the ants communicate mainly via smell. When two ants tap their antennae together, “they can smell what are called cuticular hydrocarbons, and that smell changes when they’ve been outside the nest. One ant can also tell if the other is carrying a seed, and this information is enough to regulate the entire foraging behavior of the colony.”

The model Leonard developed crunches these interactions to estimate how likely each forager is to leave the nest in search of seeds. Put together, these estimates allow them to analyze how a colony’s foraging rates fluctuate in response to environmental conditions.

To gather data for the model, Gordon’s team used videos and computer-vision software, as well as manual counts, to record 13 colonies of ants. They monitored how many of the insects entered and exited the nests during the morning hours (before it got too hot for the ants to forage) and how these figures varied from colony to colony.

The team looked at foraging behavior as a “closed-loop system” in which the environment and ants that are already foraging outside influence interactions inside the colony. In turn, this affects foraging rates. Ants coming into the colony interact with those already there, influencing their likelihood of engaging in foraging. What they wanted to understand is how environmental conditions affect each ant’s sensitivity to these interactions — something they call “sensitivity level volatility”.

It’s actually very similar to how simple interactions between neurons form our thoughts and memories, the team writes.

“The ants don’t know what the current temperature or humidity is outside the nest, so they become informed the first time they leave the nest,” Vasquez explains. “So, we proposed [that once] they’ve been outside for the first time they change how sensitive they are to interactions with returning foragers. In essence, the colony can use the accumulated information from the incoming ants to regulate how sensitive the colony is to sending out new foragers.”

“This model puts together the interactions of ants inside the nest and the rate at which they forage outside into one system, so that we can understand the process that evolution is shaping,” said Gordon. “Natural selection is acting on how this all works dynamically, and now we have a way to describe that. It’s a very elegant way to think about a lot of noisy dynamics and put it together into a model that can be used to guide further work.”

The researchers plan to expand their research by looking at the behavior of single ants throughout the day. Gordon also plans to integrate the foraging model with genetic data on the ant colonies to explore whether foraging behavior that helps the ants conserve water is heritable, since it is known to affect a colony’s reproductive success.

The paper “Regulation of harvester ant foraging as a closed-loop excitable system” has been published in the journal PLOS Computational Biology.

Dracula ants have the fastest body parts known to man: their jaws

A new study has found that their jaws can move at 90 meters per second (more than 200 mph), making it the fastest animal movement on record.

The mandibles of this Dracula ant species, Mystrium camillae, are the fastest known moving animal appendages, snapping shut at speeds of up to 90 meters per second. Image credits: Adrian Smith.

As you might infer from their name, Dracula ants (a generic name for species in the Adetomyrma genus) are pretty nasty creatures. Their name comes not from their jaws, but rather from their extremely unusual feeding habits. They practice a sort of “non-destructive cannibalism”, chewing holes into and feeding on the haemolymph (insect “blood”) of the colony’s own pupae and larvae.

Some species have also been known to drink the haemolymph of prey, and have also been observed to feed off of egg yolk. But these ants are also known for the incredible strength of their mandibles, which they can use both offensively or defensively.

“These ants are fascinating as their mandibles are very unusual,” said University of Illinois animal biology and entomology professor Andrew Suarez, who was one of the co-authors. “Even among ants that power-amplify their jaws, the Dracula ants are unique: Instead of using three different parts for the spring, latch and lever arm, all three are combined in the mandible.”

Not all that much is known about the lifestyle of these ants. They were only discovered a decade ago on a rotting log in Madagascar, and they quite confused researchers at first — because unlike many other ant species, their looks don’t necessarily betray their role in the colony. For instance, some workers sometimes become queen ants, which may or may not have wings, and these wings can be large or small. In addition, the genus has three different modes of reproduction, which makes understanding them even more challenging. However, in the new study, researchers didn’t focus on their ecology, but rather on their jaws.

Unlike trap-jaw ants, which have a pair of mandibles capable of shutting their jaws from an open position, Dracula ants power up their mandibles by pressing the tips together. This creates an internal stress that is released when one mandible slides across the other — somewhat similar to how we can snap our fingers, researchers say.

This way, they don’t necessarily bite off their opponents, but rather smack them around violently.

“The ants use this motion to smack other arthropods, likely stunning them, smashing them against a tunnel wall or pushing them away. The prey is then transported back to the nest, where it is fed to the ants’ larvae,” Suarez said. The workers use venom to stun their prey and then bring them back to the colonly to feed it to the larvae.

“Scientists have described many different spring-loading mechanisms in ants, but no one knew the relative speed of each of these mechanisms,” says Fredrick J. Larabee, a postdoctoral researcher at the Smithsonian National Museum of Natural History. “We had to use incredibly fast cameras to see the whole movement. We also used X-ray imaging technology to be able to see their anatomy in three dimensions, to better understand how the movement works.”

After they carried out computer simulations of mandible snaps from different species, researchers better understood just how the ants are capable of generating so much power and speed in their jaws. According to their results, these are the fastest moving appendages in the animal world.

“Our main findings are that snap-jaws are the fastest of the spring-loaded ant mouthparts, and the fastest currently known animal movement,” Larabee said. “By comparing the jaw shape of snapping ants with biting ants, we also learned that it only took small changes in shape for the jaws to evolve a new function: acting as a spring.”

However, it’s still not clear how all these mandibles are used in practical situations. Researchers want to better examine how Adetomyrma employ this power in offensive and defensive situations.

The paper “Snap-jaw morphology is specialized for high-speed power amplification in the Dracula ant, Mystrium camillae” has been published in Royal Society Open Science.

New ant species from Borneo detonates itself to defend its colony

This planet sure has its share of incredible life forms, and the exploding ants of Borneo can stand up with the best of them. When threatened by other insects, they rupture their own body walls, releasing a toxic, sticky liquid which kills or immobilizes their attacker.

Exploding behavior of an unfortunate Colobopsis explodens in an experimental setting with a weaver ant. Image credits: Alexey Kopchinskiy.

These ants were first mentioned more than a century ago, back in 1916. Surprisingly, they were chalked off as little more than a curiosity, and were only classified as a species in 1935. It wasn’t until 2014 that a multi-disciplinary expedition properly described them. The collaborative effort featured entomologists, botanists, microbiologists, and chemists from the Natural History Museum Vienna, Technical University Vienna, IFA Tulln and Universiti Brunei Darussalam. Together, they identified 15 separate species of exploding ants, and one of them has now been thoroughly described in the open access journal ZooKeys.

The species previously nicknamed “Yellow Goo” due to its bright yellow gland secretion, has now been named Colobopsis explodens. The species has been picked as the model species for the group, with researchers noting that its behavior is “particularly prone to self-sacrifice when threatened by enemy arthropods, as well as intruding researchers”.

The team reports that the ants have developed extreme abilities, similar to what computer games often feature. For instance, minor workers have developed the self-destructive ability to explode, taking their attackers with them. Meanwhile, some major workers (called door-keepers) have developed plug-shaped heads used to physically barricade the nest entrances against intruders.

Researchers have also observed queens and males on a mating flight, and they have sampled the first males of these ants that were ever seen. They also documented the ants’ schedule and food preferences, as well as tracked how their explosive behavior is used.

These exploding ants seem to play a dominant role in their rainforest ecosystem, but other than what has been described so far, we know very little of them. It’s fairly uncommon for creatures to develop such dramatic abilities, and the processes which led to this evolution are still unclear.

The study is just the first of many currently in preparation describing the ants’ behavior, chemical profile, microbiology, anatomy, and evolution, scientists say. The team has also set up a website, ExplodingAnts.com, where you can follow news, updates, and media from the project.

Journal Reference: Laciny A, Zettel H, Kopchinskiy A, Pretzer C, Pal A, Salim KA, Rahimi MJ, Hoenigsberger M, Lim L, Jaitrong W, Druzhinina IS (2018) Colobopsis explodens sp. n., model species for studies on “exploding ants” (Hymenoptera, Formicidae), with biological notes and first illustrations of males of the Colobopsis cylindrica group. ZooKeys 751: 1-40. https://doi.org/10.3897/zookeys.751.22661

Medical ants rescue and care for injured comrades

It’s the first time a non-human animal has been observed caring for the wounded. The behavior surprised biologists, showing just how complex ants really are.

Medical care for a wounded soldier. Image credits: Erik Frank / Youtube.

Ant wars

Matabele ants (Megaponera analis) are one of the biggest and most violent ant species in the world, being named after the Matabele tribe, fierce warriors who overwhelmed various other tribes during the 1800s. You thought termites were bad, but Matabele ants raid termites two to four times a day, killing workers and bringing them back to their nest where they feed on them. Every time they raid, squads of 200-600 marauding ants march out, preying on the termites. But the termites are not defenseless.

Termite soldiers are well-armored and strike with powerful jaws. While they are often overrun by the Matabele, they can still deal powerful blows to the invaders, heavily injuring or even killing them. As a result, it’s quite common for Matabele soldiers to lose one or several limbs.

So far, nothing uncommon, just another ruthless day in the life of insects. But after the raid, things take an unexpected turn, as medical troops come in and rescue the wounded — but only the ones that aren’t severely injured.

Healthcare for all

It all started in 2017, when Erik Frank, then at the University of Würzburg, Germany reported that Matabele ants routinely carry their wounded back to the nest. This is already unusual as most social insects (ants included) see individuals as expendable. The Matabele, however, are different. They can release a pheromone, signaling that they need help, and help is always dispatched (if physically possible). Other ants would come, pick the injured ones up, and carry them back to the nest.

Now, Frank and his colleagues, currently at the University of Lausanne in Switzerland, have found what happens after the wounded are brought to the nest.

They found that “nurse” ants “lick” the wounds of the soldiers, and this greatly increases their chances of surviving. Without this treatment, only 20% of the ants who had lost limbs survived. With it, up to 90% survived and were fit to fight another day.

It’s not clear what this treatment is doing. It could be that it simply cleans the wound to prevent infection, or the nurses could be applying an antimicrobial substance through their saliva. Either way, the similarity to human medical treatment is striking.

“We suppose that they do this to clean the wounds and maybe even apply antimicrobial substances with their saliva to reduce the risk of bacterial or fungal infection,” Frank explains.

A game of odds

But things get even more interesting. As the biologists were observing ants in Comoe National Park in Ivory Coast, they noticed another unexpected behavior. The ants do a type of field “triaging” — they decide who to help and who to leave behind.

Of course, the battlefield is a rough place and it might not always be possible to help everyone, so ants make a judgment call on who to help. But interestingly, it’s not the helpers that make this decision but rather the wounded themselves.

Ants who were lightly injured and lost one limb asked for help by releasing the pheromone and orienting their body in a way that facilitates transport (I know, losing a limb doesn’t seem like a “light” injury, but these ants often made a quick recovery and move just as fast as healthy ones). Meanwhile, badly injured ants missing five of their six legs flail wildly if someone attempts to rescue them, resisting any help. In other words, the helpless make sure that no energy is wasted on them.

“They simply don’t cooperate with the helpers and are left behind as a result,” Frank says.

Surprising ants

This study is intriguing on multiple levels. For starters, how did ants develop this behavior, what drove them to start helping their injured comrades, and why don’t other species do it?

These questions probably have a lot to do with the Matabele’s warrior behavior. They almost certainly don’t do it out of compassion, but because their colony depends on it. At one point, almost a third of the entire colony had lost at least a limb, and medical care ensures that they can still be useful members of the colony.

It’s also interesting to see just how ant nurses dress the wound, which is something Frank hopes to solve in future studies. If ants do inject some sort of antibiotic to treat the wounds, then perhaps there is a chance of adapting this antibiotic to humans.

The Matabele tribe, the ants’ namesake, often waged war against their neighbors and rose up to defend their lands against British colonists. Similarly, the ants prey on nearby termites. But presumably unlike the humans, ants have no problem in sacrificing themselves for the greater good. Why do severely injured ants act so selfless, and how do they decide when they’re beyond hope? That is another question for future studies to answer.

Journal Reference: Erik T. Frank, Marten Wehrhahn, K. Eduard Linsenmair. Wound treatment and selective help in a termite-hunting antDOI: 10.1098/rspb.2017.2457

Study reveals how ants produce antibiotics

Like humans, ants sometimes struggle with infections. But unlike humans, some ants produce their own, strong antibiotics, on the surface of their body. A new study looked at which species can do this, and how in turn, their ability could enable us to develop better antibiotics.

The Thief Ant (Solenopsis modesta) produced the strongest antibiotics. Image credits: Michael Branstetter / AntWeb.

“These findings suggest that ants could be a future source of new antibiotics to help fight human diseases,” says Clint Penick, an assistant research professor at Arizona State University and former postdoctoral researcher at North Carolina State University, who is lead author of the study.

Researchers tested the antimicrobial properties associated with 20 ant species. Out of them, 8 didn’t produce any antibiotic (40%), but the rest did. In particular, one species produced an impressively powerful antibiotic.

“One species we looked at, the thief ant (Solenopsis molesta), had the most powerful antibiotic effect of any species we tested – and until now, no one had even shown that they made use of antimicrobials,” says Adrian Smith, co-author of the paper, an assistant research professor of biological sciences at NC State and head of the NC Museum of Natural Sciences’ Evolutionary Biology & Behavior Research Lab.

To assess the ants’ antibiotic-producing abilities, researchers used a solvent to remove all of the substances on the surface of each ant’s body. They then introduced these substances into a slurry of bacteria and compared how the slurry of bacteria grew for each of the ant species. The stronger the antibiotic, the less the bacteria would grow.

You can watch a video documenting the process below.

The results could be significant for a number of reasons. For starters, it could allow doctors to develop better human antibiotics. But it’s also important from a biological standpoint.

“Finding a species that carries a powerful antimicrobial agent is good news for those interested in finding new antibiotic agents that can help humans,” Smith says. “But the fact that so many ant species appear to have little or no chemical defense against microbial pathogens is also important.”

Researchers aren’t sure why some ants appear to not have any antibiotic-producing activities. Traditional knowledge postulated that all ant species produce some antibiotic but if this is not the case, it might mean that they’ve developed a different way to protect themselves, and this may also be promising to investigate.

“We thought every ant species would produce at least some type of antimicrobial,” Penick says. “Instead, it seems like many species have found alternative ways to prevent infection that do not rely on antimicrobial chemicals.”

The team wants to explore this further. They plan on testing more ant species against even more bacteria species, and they also want to determine exactly how and where in their body the ants produce the antibiotics.

The paper, “External immunity in ant societies: sociality and colony size do not predict investment in antimicrobials,” is published in the journal Royal Society Open Science.

L. vladi.

Ugly Unicorn: Metal-tipped prehistoric ant drank the blood of its victims for dinner

A newly-described species of ant is so outlandishly frightful that it can only be called “hell ant.”

Hell ant.

Image credits P. Barden et al., 2017.

Brandishing upward-facing blades in lieu of regular mouth pieces, a metal-infused feeding horn, and the vampiric diet to go with the lot, Linguamyrmex vladi seems custom-tailored to star in every nightmare you’ll ever have. Fret not, however, for the species has been extinct — along with its extended lineage — since the Cretaceous.

The insect has just been described by a team from the New Jersey Institute of Technology in Newark led by Dr Phillip Barden. Nicknamed the “hell ant,” the insect was found preserved in 98-million-year-old amber and has a freakishly brutal anatomy.

The ant to rule them all

This insect is armed to the teeth — literally. The hell ant traded its mandibles for spike-like blades, which look pointy and unpleasant. This unique physiognomy, however, also posed a few issues for the team. It’s unlike anything living today, which made describing and understanding how Linguamyrmex vladi lived quite the challenge.

However, the team managed to find one feature which links them to modern species —  short hairs around hell ants’ mouths. These are highly similar to those seen in trap-jaw ants (genus Odontomachus) which cause their jaws to snap shut when triggered. This led the team to suspect that the hell ants’ jaws functioned in a similar way, and helped them piece together the rest of its story.

L. vladi.

(A) Lateral view of the ant. (B) View of head capsule and mesosoma. Scale bars are 0.5 mm / 0.02 inch. Whoa..
Image credits P. Barden et al., 2017.

This is quite fortunate because that ‘rest of the story’ is pretty metal as well. L. vladi also had a deadly horn jutting out over its blade-like mandibles. Whenever some insect touched the hairs, the hell ant’s mandibles would contract, flipping its prey and punching the horn through its armored outer layers. The team describes a structure on the ant’s head that seems designed to absorb the force of the jaws:

“You have this sort of stopping plate, made to accommodate the mandibles closing and capturing prey,” says Barden.

In fact, based on CT scans performed on the ambered insect, the team says L. vladi’s clypeal paddle (the bit of its head where the jaws are set and elongates to form the horn) was covered in a layer reinforced with metal.

“This reinforcement occurs primarily along the centre of the paddle and, as the specimen is preserved with the mandibles largely ‘closed’ and positioned near this spot, suggests that the reinforcement is intended to accommodate mandibular impact,” they write.

Paper co-author Vincent Perrichot explains that the metal likely helped “keep the horn undamaged,” a method which some insects today still use to reduce wear and tear in areas that usually take a battering, adds Barden.

Anatomy.

Image credits P. Barden et al., 2017.

Not content with merely being the ant equivalent of an evil, metal-sheathed unicorn, L. vladi was also likely a vampire. When its mandibles moved upwards, the team reports, they formed a ‘gutter’ which was likely used to funnel haemolymph (bug blood) down the hell ant’s “mouthparts,” Barden explains. The team also found a beetle grub preserved alongside L. vladi in the amber, the kind of “squishy, haemolymph-laden insect” that could underpin its diet. Judging from its metal-tipped weaponry, however, it’s likely that L. vladi could easily penetrate the armor of adult insects as well.

“Until we find a specimen with the prey item trapped, which is probably a matter of time, we’re left to speculate,” says Barden.

The Myanmar, Burma, amber deposits where this ant was found are thankfully very rich, so we may find just what the team needs sometime soon.

The paper “A new genus of hell ants from the Cretaceous (Hymenoptera: Formicidae: Haidomyrmecini) with a novel head structure” has just been published in the journal Systematic Entomology.

bullet ant

Worst pain known to man is caused by world’s largest ant

Quick: Imagine the worst pain you’ve felt. Now, triple it.

That may sound really harsh, but believe it or not, chances are it would still not come close to being stung by the bullet ant, the largest ant in the world. Native to the western rainforests of South America, this insect packs a nasty venomous bite that’s believed to be thirty times more painful than a bee’s sting.

Arguably, it’s the worst pain known to man

bullet ant

Credit: Fewell Lab at Arizona State University

“With a bullet ant sting, the pain is throughout your whole body,” adventurer and naturalist Steve Backshall described on a recent episode of the BBC’s Infinite Monkey Cage. “You start shaking. You start sweating […] It goes through your whole body.”

“Your heart rate goes up, and if you have quite a few of them, you will be passing in and out of consciousness. There will be nothing in your world apart from pain for at least three or four hours.”

Like bees, however, Parponera clavata will only release its potent venom in defense, when threatened. Unlike other ants, there are usually only a few hundred of them in each colony or nest. Nests are usually located at the bases of trees. The worker ants forage all the time in the trees, even getting up to the canopy, but seldom forage on the forest floor. The queen Bullet Ant is a lot bigger than the workers (who are usually about 20 to 30 mm in length). The workers are unyielding, look a bit like a wingless wasp, are reddish-black in color, and are very predacious.

bullet-ant-glove

It’s waiting! Image: The Drip Tray

Some people are hardcore masochists, though, and actively seek the pain. In the case of tribesmen of the Satere-Mawe in Brazil, the reward for wrestling with the bullet ant is manhood. To become initiated as a warrior, teenage boys must wear gloves filled with numerous bullet ants woven in, stinger facing inside, for a full five minutes. During this whole rite, it’s imperative you maintain a calm composure. Initiates must repeat the process at least 20 times to ascend to manhood.

It comes at a price, though. Each session leaves the hand swollen, bruised, and paralyzed temporarily. The boy in question might experience uncontrollable shakiness for days after the rite. That’s why the 20 trials are spread out over several months. One documentary filmmaker, Hamish Blake, tried on the ant gloves for an Australian TV documentary. He could only bear wearing the gloves for a few seconds, which earned him eight hours of excruciating pain.

For what it’s worth, though, the bullet ant’s venom doesn’t last that long. The bruises heal quickly, and the paralysis fades away. In a mere 24 hours, the active ingredient, a neurotoxin called poneratoxin, is completely flushed out of the body. According to toxicological estimates, it would take 2,250 stings to kill a 165-pound human.

“It’s an almost completely pure neurotoxin,” Backshall said. “One of the reasons why people can use it for tribal initiation ceremonies is because although it causes extraordinary pain, it’s not dangerous. There’s almost no allergens. There’s no danger of a histamine reaction to the venom.”

[MORE] Scientist finds the worst places to get stung by a bee – by experimenting on himself. In order, it’s the nostril, lip, and penis

It’s easy to understand why the Satere-Mawe revere their practice so much. Following the rite, the body is completely filled with adrenaline — a rush that can last for weeks.

Adrenaline is a key component of our body’s fight-or-flight response and is used to squeeze every last drop of performance out of our bodies in order to keep us alive. It’s most obvious effects include increased blood flow to muscles, output of the heart, and increased pupil dilation. Adrenaline also primes our internal organs for emergency — it increases blood sugar level, alters which compounds our bodies prioritize during digestion, and how we perceive emotion (it shifts everything closer to fear and/or aggression). On the bright side, it makes us more alert, pushes our muscles into overdrive, and makes us more focused.

Because the bullet ant’s bite is so immensely painful, and because of the sheer number of bites a Satere-Mawe would be exposed to during their initiation right, their nervous systems register it as a particularly dangerous threat — and release a deluge of adrenaline to help them fight it off or run away from it.

“You have such a massive overdose of adrenaline that you feel like a god. For a week afterwards I felt like if I leapt off a cliff I could have flown,” Backshall said.

Ironically, poneratoxin is being explored as a possible pain reliever. In subtle doses, some have found it acts to block pain.

Left: some grumpy old men. Right: Pheidole dentata, a native of the southeastern U.S. The ant isn't immortal, but doesn't seem to age.

Forever young: ants don’t seem to age

Most people don’t have that much of an issue with dying, like they do with being freaking old. Being old is a drag. You gain weight, the skin gets wrinkled, the mind and body weakens — and it all gets gradually worse until you expire. Ants don’t seem to share this human tragedy. By all accounts these particular ants don’t seem to age and die in youthful bodies.

Left: some grumpy old men. Right: Pheidole dentata, a native of the southeastern U.S. The ant isn't immortal, but doesn't seem to age.

Left: some grumpy old men. Right: Pheidole dentata, a native of the southeastern U.S. The ant isn’t immortal, but doesn’t seem to age.

This is according to researchers at Boston University who followed Pheidole dentata worker ants in a lab environment. These ants live to grow 140-days old, and the team suspected that these should show similar signs of aging like most organisms seeing how they seem to develop repertoires and behavior with age. “We expected that there would be a normal curve for these kinds of functions — they’d improve, they’d peak and then they’d decline,” James Traniello said, one of the study’s authors.

The researchers carefully looked for signs of aging from dead cells in the brain, to lower dopamine levels to declining performance in daily tasks. None of it was observed. It seems like these ants performed with flying colours until they die, like a bright flame that’s suddenly extinguished when the job is done. Moreover, the ants seemed to get better and better at anty-stuff (carrying food, finding resources) and became more active with each passing day in their lives.

Such displays are rare in the animal kingdom. Another notable examples includes naked mole rats which are arguably more impressive. These live for up to 30 years and stay spry for most of this time.

For now, scientists don’t know why these ants don’t seem to age, but being extremely social (part of the hive) might have something to do with it, they report in Proceedings of the Royal Society B. For sure, follow-up studies will be made on other ant species.

“Maybe the social component could be important,” says says Ysabel Giraldo, who studied the ants for her doctoral thesis at Boston University. “This could be a really exciting system to understand the neurobiology of aging.”

This might seem like an epiphany. Maybe there’s a way to transmute ants’ secret fountain of youth to humans. That would certainly make a lot of people happy, but it would likely never work. Ants are alien compared to humans. For one ants don’t reproduce and use a lot less oxygen. Given how complex the human organism is, it would never be feasible to mimic the ant’s way of life.

Don’t look so dull. Being human has its perks. Guess we’ll just have to come to terms with old age, until someone finds the Holy Grail.

Crops farmed by leafcutter ants show signs of domestication: Leafcutter ants became farmers 50 million years before humans

Leafcutter ants in South America grow fungus as crops, this has been known for quite a while. But their crops show clear signs of domestication, which means that when it comes to farming, the ants might have beaten us by some 50 million years.

Ant farmers

Atta cephalotes tending to their garden. Image credits: Alexander Wild.

When people started growing crops, they unwittingly made changes to the plants’ genome. For example, wheat, bananas, tobacco and strawberries are all polyploid – more than two paired (homologous) sets of chromosomes.  Now, Danish researchers from Copenhagen have found that leafcutter ants crops exhibit similar traits. While natural fungus and the one grown by less specialized ants consistently has two copies of each set of chromosomes, leafcutter crops are ployploid, having between five and seven copies. This is a major indication that a plant (or in this case, a fungus) is becoming domesticated.

“Polyploidisation is the fastest way to make a domesticated crop,” says Rachel Meyer from New York University. It makes it larger and more robust because it increases the number of copies of each gene, producing more gene products like growth hormones and immune proteins.

Early humans favored polyploid plants for their productivity and increased yield, and the same is probably happening with the ants.

“About 50 million years ago, fungus-growing ants gave up their lives as hunter-gatherers to become fungal farmers,” says Kooij. He thinks the leafcutters took it further by selecting the more productive, polyploid fungi and encouraging their growth.

 

There was another similarity between the ants and early human farmers: as agriculture developed, populations grew by several orders of magnitude. Unspecialized ants can have colonies of thousands or tens of thousands of workers, while leafcutter ant colonies number in the millions. These extremely successful insects basically dominate the rainforest, with a single colony having yields of up to 500 kilograms from their fungal crops.

“The results of our study provide yet another piece of the puzzle to explain how these ants have been so extremely successful,” says Kooij.

Image via Bilfinger.

Ants, fungus and bananas

Previously, the ant-fungus relationship was considered a type of symbiosis, but more and more research has hinted to the idea that the ants are actually growing the fungus, and this is not simply a biological relationship. Fungus-growing ants actively propagate, nurture and defend the fungus. When a queen starts a new colony, she actually takes a pellet of the fungus with her, starting a new garden at the new colony site. The relationship is so specialized that in most cases, the fungus doesn’t even grow outside the ant colonies, and there are no ant colonies without the fungus – it’s strikingly similar to human agriculture.

But there’s another side to it: polyploid species are often unable to reproduce sexually, which means that there is less risk for breeding with external species. This means that the crop is limited to asexual reproduction: this also means that plants like bananas for example have no seeds, which makes them tastier for us. It seems logical that the same is happening for ants.

“Humans have made edible bananas, bigger sugarcane and strawberries,” says Meyer. “And we’re currently making new polyploids for bigger kiwi fruit and seedless watermelon.”

So, as I was discussing with some friends, does this mean that ants are intelligent? This seems to suggest so.

Journal reference: Journal of Evolutionary Biology, DOI: 10.1111/jeb.12718

Watch: How Ants React to a Ringing iPhone

As soon as the phone starts ringing, these ants have a military-like reaction, forming a circle around the device. But why do they do this? The answer is almost certainly ‘due to magnetic fields’.

Like many other insects, ants rely on magnetic fields to find their way around – they have internal magnetic compasses that help them navigate. When the phone starts ringing, the radio waves likely disturb their internal compass and this makes them want to avoid the phone. Australian entomologist Nigel Andrew from the University of New England:

“A lot of ants use magnetism to orientate themselves. [They] have magnetic receptors in their antennae,” he said. “If they’re travelling long distances they use magnetic cues from Earth to know if they are going north, east, south or west.”

But even if we weren’t talking about ants, forming ordered circles is actually surprisingly natural. Many organisms (ants included) tend to form circles, as ustralian social insect researcher Simon Robson from Queensland’s James Cook University (JCU) told ninemsn. 

“There are many ants that actually start forming in a circle without the phone,” Mr Robson said.”It’s an unavoidable consequence of their communication systems. Having the ants together like that, the shape of the phone may have something to do with it and the vibration might get them a bit more excited, but a lot of ants will do it even without the phone.”

In the meantime, the video has gone viral and is delighting millions of viewers around the world. Now, you also have an explanation for it.

ant smell

Ants can tell who’s who using their crazy sense of smell

Maybe the most amazing of social insects, ants use complex cues of pheromones to determine to which cast in the colony each individual ant belongs to. A team at University of California at Riverside found ants do this by sniffing out hydrocarbon chemicals present on their cuticles (outer shell). These cues are extremely subtle, but the ants can sense them with great sensitivity due to the way they’re hardwired. It’s enough to notice that ants have more olfactory receptor proteins in their genome than we humans have. Amazing!

ant smell

Ants communicate with each other using pheromones, sounds, and touch. Like other insects, ants perceive smells with their long, thin, and mobile antennae. Image: Fragrantica

Previously, some biologists gathered around the hypothesis that worker ants could preferentially smell only non-nestmate cuticular hydrocarbons. The hypothesis suggested that ants aren’t sensitive enough to pick up hydrocarbons from nestmates with which they share too many pheromones. Anandasankar Ray, a neuroscientist and an associate professor of entomology, wasn’t entirely convinced, though.

Him and colleagues at UC Riverside decided to go the root and study antennal neurons and their responses to hydrocarbons on the cuticle. The team individually studied the neural activity of Camponotus floridanus ants as these came in contact with hydrocarbons – long chains of hydrogen and carbon molecules. The method they used is called  electrophysiology, and involved training the ants to associate certain hydrocarbons with sugary water, then measuring the electrical response of the neurons to these reactions. To their surprise, the researchers found the ants could distinguish between various forms of hydrocarbons with extreme sensitivity.

“These guys can smell almost any hydrocarbon we offered to them,” Ray said for Washington Post. “Along with it, we also discovered not only did they have a very extensive olfactory system, they are also able to distinguish very well between very closely related [compounds]. They are able to tell the difference between a hydrocarbon with 25 carbon atoms versus 24 atoms.”

“This broad-spectrum ability to detect hydrocarbons by the ant antenna is unusual and likely a special property of social insects. Using this high-definition ability to smell ‘ant body odor’ the ants can recognize the various castes in the colony as well as intruders,” Ray added.

When you go deeper into this, it starts making sense too. Hydrocarbons are low volatility compounds, meaning you have to be very close to them to pick them up, even if you’re a super sniffer like an ant. If they had gotten their cues from some different compound, say much more volatile, it would have been impossible for the ants to distinguish one another. A language becomes powerful when it is complex and meaning can be conveyed as specifically as possible. That’s what words are for. For ants, their language is chemical and cues have to be very subtle.

The broad-spectrum sensitivity of Camponotus laevigatus allows these ants to detect CHCs from both nestmates and non-nestmates.  Image: Cell Reports

The broad-spectrum sensitivity of Camponotus laevigatus allows these ants to detect CHCs from both nestmates and non-nestmates. Image: Cell Reports

Ultimately, depending on the cast it belongs to (queen, worker, warrior), each ant has its own blend made up of several cuticular hydrocarbons, the authors write in Cell Reports.

“We are closing in to finding the functional roles of these receptors, and, in particular, finding the olfactory receptors that detect pheromones from the queen who regulates much of the order in the colony,” Ray says.

ant colony

Ants surprisingly agile even in microgravity, ISS experiment shows

Eight colonies of common ants were shipped to the International Space Station last December to study how microgravity might affect the creatures. So, how did the ants fare? Well, surprisingly good actually. The dexterous ants clung to the surface of the station and migrated freely (under supervision of course) despite weightlessness. Of course, their movements weren’t as coordinated as on Earth and since they rely on a sort of hive mind to coordinate the colony, researchers believe studying their mishaps in microgravity might aid build better robots.

ant colony

Image: Flickr cyron

 

The colonies were held in a small arenas and left to roam in two separate areas. According to the researchers, the ants  “explored the area less thoroughly” and “took more convoluted paths” which is likely due to the difficulties of holding on the surface as a result of microgravity. Nevertheless, the ants were agile when climbing surfaces and , most surprisingly, rebounded rather successfully when they slipped.

“The ants showed an impressive ability to walk on the surface in microgravity, and an even more remarkable capacity to regain their contact with the surface once they were tumbling around in the air,” researchers wrote in the journal Frontiers in Ecology and Evolution.

When the ants lost contact with the station’s surface, it was usually because they  tumbled or skidded too rapidly. When they fell, the ants turned in the air or quickly skipped in a direction, suggesting they were exerting great pressure on the surface walls. Though bees and ant colonies both have queens, these do not control the colony – they mainly have reproduction responsibilities. Thus, the colony coordinates itself through a hive mind emerging from uncoordinated decisions made by individuals (read Out of Control by Kevin Kelly, the most brilliant book on the subject). For instance, take foraging trails: the long, tiny highways used by ants to shuffle food like leaves or bread crumbs back and forth to the colony. These form when ants leave a chemical path sprinkled with pheromones. Since the ants have a slight tendency to move towards the pheromone, they follow the chemical path and reinforce it, soon forming a trail. It’s enough for one ant to start the trail, and the rest follow suit. This kind of behaviour makes it possible for colonies to solve challenging problems, like finding the shortest path to food, without any kind of centralized planning or decision making.

In microgravity, many areas were virtually unexplored by the ants, something that was highly unlikely to happen with control ants back on Earth. By learning what helps or, on the contrary, hamper collective search operations researchers pave the ways for intelligent, similarly hive-mind robot swarms.

Voracious Plant Outsmarts Ants Even Without a Brain

Having a smart strategy doesn’t require a brain, a new study has shown. Researchers found an insect-eating plant from Borneo which can outsmart ants and temporarily turn off its trap to attract more prey.

A carnivorous pitcher plant. Image via Wiki Commons.

Carnivorous plants are plants that derive some or most of their nutrients (but not energy) from trapping and consuming animals or protozoans, typically insects and arthropods. They still photosynthesize, but they also like a tasty snack once in a while. The Asian carnivorous species of plant from Borneo are called pitcher plants, due to their cup-shaped traps for the insects which resembles a pitcher. Pitcher plants can easily capture and trap ants due to the plant’s margins that become wet and very slippery. When the prey walks on the edges of the flower, it falls inside the cup and is trapped there. But this plant has developed a different strategy – instead of eating one ant at a time, it devised a strategy to eat more insects in one meal.

The plant can make its edge slippery or safe, and it does so depending on what it wants.

“The plant’s key trapping surface is extremely slippery when wet, but not when dry,” explained project leader Ulrike Bauer of Bristol University’s School of Biological Sciences. “For up to eight hours during dry days, these traps are ‘switched off’ and do not capture any of their insect visitors. At first sight, this is puzzling because natural selection should favor traps that catch as many insects as possible.”

The thing is, ants don’t all march in at once – they have individual scouts that go ahead and see if a route is safe. If the scouts find that the plant’s edge is not slippery, they come in with nectar. Pretty soon, the ants will return in bigger numbers to retrieve more nectar, but they will have a sad surprise – the edge of the plant has become slippery again, trapping many of them in one go. So the plant chooses to let the scouts go and lure in more ants to feast upon. The plant’s strategy appears to be extremely successful, biologists report.

“Of course a plant is not clever in the human sense – it cannot plot. However, natural selection is very relentless and will only reward the most successful strategies,” said biologist Ulrike Bauer of Britain’s University of Bristol, who led the study being published on Wednesday in the scientific journal Proceedings of the Royal Society B.

However, what may seem like a win for the plant may actually be a case of mutual advantage. The plant gives away some of its nectar in exchange for some ants, and while it’s not clear yet, this may be beneficial for the ant colony.

“By ‘switching off’ their traps for part of the day, pitcher plants ensure that scout ants can return safely to the colony and recruit nest-mates to the trap,” Bauer said. “Later, when the pitcher becomes wet, these followers get caught in one sweep. What looks like a disadvantage at first sight, turns out to be a clever strategy to exploit the recruitment behavior of social insects.”

Carnivorous plants are usually found in nutrient-poor environment, which is why they need to compliment their diet. Foraging, flying or crawling insects such as flies are attracted to the cavity formed by the cupped leaf, often by visual lures and nectar bribes.

ants city garbage

City ants are garbage eating, rat-fighting machines

Ants often get a lot of bad rep for being “pests” in the city, but a new study has shown that ant populations are actually very helpful in urban environments. Scientists researching the behavior of ants have found that they dispose of garbage with remarkable efficiency, keeping rats and other garbage-dependent pests at bay.

ants city garbage

City dwelling ants are very effective garbage disposers. Image via UT Static

“Urban green spaces provide ecosystem services to city residents, but their management is hindered by a poor understanding of their ecology. We examined a novel ecosystem service relevant to urban public health and esthetics: the consumption of littered food waste by arthropods”, researchers introduce their paper.

The study was already well underway in 2012, when Hurricane Sandy struck New York; they decided to take advantage of this new setting and also observe how the behavior of insect populations changed. What they found was pretty surprising – ants are very effective at eliminating garbage; the ants that live on the median of Broadway alone can eat up to 60,000 hot dogs a year! They sampled ants and millipeds in street medians and parks by placing weighed samples of commonly dropped foods — hot dogs, cookies and chips — into wire mesh cages that only ant-sized creatures could crawl into. Next to these set ups, they put the same bait, but in the open, available for any creature to come and eat. After 24 hours they took both samples back, to see how much garbage ants alone eat compared to all the garbage-eating population combined. This is how they found that ants eat a lot of food, but they also learned that ants on the street eat much more than those in parks.

“We thought, oh, the parks, with their more diverse species — that’s where we’re going to see the ants doing a more thorough job. So we were surprised when the opposite was true,” said lead author Elsa Youngsteadt, a research associate at North Carolina State University.

As it turns out, even though street populations are less diverse, they eat 2-3 times more garbage than those in parks. Scientists believe that the pavement ants (so named for their habitat of choice) are probably the voracious eaters causing the imbalance.

“We calculate that the arthropods on medians down the Broadway/West St. corridor alone could consume more than 2,100 pounds of discarded junk food, the equivalent of 60,000 hot dogs, ever year-assuming they take a break in the winter,” said Elsa Youngsteadt, one of the researchers, in a news release. “This isn’t just a silly fact. This highlights a very real service that these arthropods provide. They effectively dispose of our trash for us.”

ants city garbage

Ants on Broadway alone can eat the equivalent of 60,000 hot dogs a year

Indeed, we often tend to forget that insects are not just there to annoy us – they provide valuable ecosystem and even urban services. If the ants on a single street consume that much garbage, can you imagine what kind of service they provide for an entire city like New York? Unfortunately, most people still only see ants as a pest. When Youngsteadt was setting up her cages for the experiment, she said, a passerby asked her about her work.

“When he found out I studied ants, he said, ‘I sure hope you’re figuring out how to kill them.’ They’re definitely not popular,” Youngsteadt said. “But this study highlights that they have a purpose in the city ecosystem that we don’t even notice. They may be taking away food from rats, who it’s safe to say we like even less.”

Indeed, ants aren’t the only garbage-loving populations. The openly-placed bait food clearly showed that ants are fighting for this resource with other populations, most notably rats.

This study shows that ants play a very important role in a big city – they are effectively garbage cleaners. Oh, and even a hurricane can’t stop them. When Hurricane Sandy flooded many of the research sites with salty water, the team expected to see a drop-off in activity there – but ant populations emerged just as hungry as ever.

“You’d think that several feet of salt water would deter some ants,” Youngsteadt said. She’s not sure why they didn’t drown — it’s possible they just weren’t submerged for long enough. “But it’s good news for urban ecosystems. They’re going to stick around and keep doing their thing no matter what — even when a disaster happens.”

Ants are awesome, we should try to better understand them, and, I feel, we should respect them more.

Journal Reference: Elsa Youngsteadt, Ryanna C. Henderson, Amy M. Savage, Andrew F. Ernst, Robert R. Dunn and Steven D. Frank. Habitat and species identity, not diversity, predict the extent of refuse consumption by urban arthropods. Article first published online: 2 DEC 2014 DOI: 10.1111/gcb.12791

Invasive ant has bear trap-like jaw which can propel it through the air

An invasive ant has been sweeping through southeastern United States; it has a jaw like a bear trap, which close faster than almost anything in nature. Naturally, it packs quite a sting, and if that wasn’t enough, it can propel itself through the air like a rocket.

Photograph by Alex Wild, Visuals Unlimited/Corbis.

“They look like little hammerhead sharks walking around,” said D. Magdalena Sorger.

That amazing jaw is so powerful that you can use it as a surgical staple (when adequate medical equipment is lacking). Especially in military situations, these ants can be quite useful in suturing wounds. But more often than not, their interactions with humans are not pleasant.

There are four species of trap-jaw ants native to the United States, and one of them was the focus of this research.  Odontomachus haematodus is especially aggressive. The species is  found in the tropics and subtropics throughout the world, but in the past 50 years it has grown its populations more and more in the US Gulf Coast. So what changes in the past half century ?

Sorger says population growth and climate change paved the way for this invasion, but the magnificent jaws also helped.

“Trap-jaw ants have little sensory hairs on the inside of their jaws,” said Sheila Patek, a biologist who studies the evolutionary mechanics of movements at Duke University. Patek explained that these hairs are linked directly to the muscles that hold the jaw open. “So they can fire those latch muscles even faster than their brain can process.”

Hey, and as if having one of the strongest bites (per size) in the animal kingdom wasn’t enough, the trap-jaw ants can actually bite the ground with so much strength that it propels them into the air – like popcorn from a frying pan. When a whole army of invasive ants does this at once, it can get a little scary.

“The next thing you know you have this ant flying through the air that you can’t even see, it’s moving so fast, with a big stinger on the end of its abdomen,” she said. “It is really nerve-racking working with them.”

The good thing is that unlike other invasive ants, these ones don’t have colonies, and therefore there’s a much reduced chance of them overwhelming the local flora and fauna – but that doesn’t mean that they won’t have a huge impact. They’re here, and we should be prepared for it.

An electron microscope shows the neck region of the Allegheny mound ant. Ohio State University

Ant biomechanics might inspire the super robots of the future

An electron microscope shows the neck region of the Allegheny mound ant. Ohio State University

An electron microscope shows the neck region of the Allegheny mound ant. Ohio State University

Ants are one of the most fascinating and extraordinary organisms on Earth. The ant society is extremely stable, compact and adaptable, but while ants can only survive as a colony, taken individually each ant is extremely remarkable by itself, too. Body size considered, ants are among the strongest beings in the world, capable of lifting and carrying objects a couple of times their own body weight. How do ants do this and is there a way human society might benefit from this knowledge? Agile and super powerful robots designed analogous to ants could be capable of much more than their contemporary clumsy brethren. A team of researchers at the Ohio State University has began to unravel this mystery.

ohio_staeTheir study focused on the single most sensible ant body part – the neck. The single joint of soft tissue that bridges the stiff exoskeleton of the ant’s head and thorax. When an ant carries food or any other object, the neck joint supports the full weight of the load.

“Loads are lifted with the mouthparts, transferred through the neck joint to the thorax, and distributed over six legs and tarsi that anchor to the supporting surface,” explained Carlos Castro, assistant professor of mechanical and aerospace engineering at Ohio State. “While previous research has explored attachment mechanisms of the tarsi (feet), little is known about the relation between the mechanical function and the structural design and material properties of the ant.”

A sturdy neck

To understand how the ant’s neck is capable of withstanding such great pressure, the Ohio State researchers developed 3-D models of the internal and external anatomy of an Allegheny mound ant (Formica exsectoides). These were made by introducing X-ray cross-section images (microCT) of ant specimens into a modeling program (ScanIPþFE) that assembled the segments and converted them into a mesh frame model of more than 6.5 million elements. The finite element analysis was then processed on the powerful Oakley Cluster, an array of 8,300 processor cores (Intel Xeon) at the Ohio Supercomputer Center.

A cross-section of an ant’s neck joint, part of a 3-D model created on OSC systems, helped Ohio State researchers to study the strength of the small insect. The cross-section shows the head (blue), neck membrane (purple), esophagus (teal), and thorax (orange). [Castro/OSU]

A cross-section of an ant’s neck joint, part of a 3-D model created on OSC systems, helped Ohio State researchers to study the strength of the small insect. The cross-section shows the head (blue), neck membrane (purple), esophagus (teal), and thorax (orange). [Castro/OSU]

 

In conjunction with the simulation, lab experiments were carried out that used a centrifuge to measure changes in the ants’ anatomies under a range of calculated loads. Both models and experiments revealed that the ant’s neck joints could withstand loads of about 5,000 times the ant’s body weight, and that the ant’s neck-joint structure produced the highest strength when its head was aligned straight, as opposed to turned to either side.

“The neck joint [of the ant] is a complex and highly integrated mechanical system. Efforts to understand the structure-function relationship in this system will contribute to the understanding of the design paradigms for optimized exoskeleton mechanisms,” said former Ohio State student Vienny N. Nguyen in her 2012 master’s thesis on this research.

“As we look to the future of human-assistive devices and ultra-light robotics,” she said, “the development of 3-dimensional models for visual analysis and loading and kinematic simulation will also serve as tools for evaluating and comparing the functional morphology of multiple species and types of joints.”

Findings appeared  in the Journal of Biomechanics.

Harpegnathos saltator ants undergo dramatic physiological changes triggered by heightened dopamine levels, following ascension of the colony's social ladder. It's not just in their heads, when these ants climb in their society, they change their bodies as well!

Brawls for colony domination transforms winning worker ants into queens without DNA changes

Harpegnathos saltator ants undergo dramatic physiological changes triggered by heightened dopamine levels, following ascension of the colony's social ladder. It's not just in their heads, when these ants climb in their society, they change their bodies as well!

Harpegnathos saltator ants undergo dramatic physiological changes triggered by heightened dopamine levels, following ascension of the colony’s social ladder. It’s not just in their heads, when these ants climb in their society, they change their bodies as well! Photo: scienceblogs.com

In the animal kingdom, especially among those that are social, you’ll see a number of strategies employed to help the group’s chances of surviving. To each his own. For instance most ant colonies employ a social hierarchy where most members, like the worker ants, are rendered functionally sterile and only the absolute top of the ladder is allowed to reproduce (the queen). A particular ant species stands out in this respect because of the uncanny behavior of some of its worker ants, who are able to morph into queens – that is to obtain reproductive capabilities – by suffering dramatic physical changes. All, however, without any chances succumbing to the DNA code. Now, researchers at North Carolina State University, Arizona State University and the U.S. Department of Agriculture have found out why and how this happens: more dopamine.

A morphing ant

The Indian jumping ants (Harpegnathos saltator) are one of the most fascinating insects and an unique ant species. When an H. saltator colony’s queen dies, the female workers engage in ritual fights to establish dominance. While these battles can be fierce, they rarely result in physical injury to the workers. Ultimately, a group of approximately 12 workers will establish dominance and become a cadre of worker queens or “gamergates.”

Here’s where the interesting stuff happens, though. The worker ants who have proven themselves to be part of the elite undergo dramatic physical changes:   their brains shrink by 25 percent; their ovaries expand to fill their abdomens; and their life expectancy jumps from about six months to several years or more. These changes occur after certain genes are either switched on or off, which in turn are influenced by environmental factors, thus epigenetics.

“We wanted to know what’s responsible for these physical changes,” says Dr. Clint Penick, lead author of a paper describing the work and a postdoctoral researcher at NC State. “The answer appears to be dopamine. We found that gamergates have dopamine levels two to three times higher than other workers.”

Dopamine: the winner’s hormone

The researchers took a subset of workers from a colony (Colony A) and separated them from their gamergates. These workers effectively formed their own colony (Colony B) and began fighting to establish dominance, as expected. Those workers who began to distinguish themselves as future gamergates of Colony B were removed at their own turn from the colony. Subsequent analysis reveled that these dominant ants produced more dopamine than regular worker ants, yet still lower than full fledged gamergates.

Finally, the researchers introduced these dominant worker ants back to colony A where the workers there recognized the changes in the dominant workers and exhibited “policing” behavior, holding down the dominant ants so that they couldn’t move. Within 24 hours, the dopamine levels in the dominant workers had dropped back to normal; they were just regular worker ants again. This proved that dopamine was the key factor that elicited this kind of behavior and triggered the massive physiological changes witnessed by the researchers.

“This tells us that the very act of winning these ritual battles increases dopamine levels in H. saltator, which ultimately leads to the physical changes we see in gamergates,” Penick says. “Similarly, losing these fights pushes dopamine levels down.”

The findings, reported in a paper published in The Journal of Experimental Biology, could help shed light on other similar social behaviors reported in other insects.

“Policing behavior occurs in wasps and other ant species, and this study shows just how that behavior can regulate hormone levels to affect physiology and ensure that workers don’t reproduce,” he explains.