Geoengineering to cool earth: Space dust as Earth's sun shield

On a cold winter day, the warmth of the sun is welcome. Yet as humanity emits more and more greenhouse gases, the Earth'satmosphere traps more and more of the sun's energy and steadily increases the Earth's temperature. One strategy for reversing this trend is to intercept a fraction of sunlight before it reaches our planet. For decades, scientists have considered using screens, objects or dust particles to block just enough of the sun's radiation -- between 1 or 2% -- to mitigate the effects of global warming.

A University of Utah-led study explored the potential of using dust to shield sunlight. They analyzed different properties of dust particles, quantities of dust and the orbits that would be best suited for shading Earth. The authors found that launching dustfrom Earth to a way station at the "Lagrange Point" between Earth and the sun (L1) would be most effective but would require astronomical cost and effort. An alternative is to use moondust. The authors argue that launching lunar dust from the moon instead could be a cheap and effective way to shade the Earth.

The team of astronomers applied a technique used to study planet formation around distant stars, their usual research focus. Planet formation is a messy process that kicks up lots ofastronomical dust that can form rings around the host star. These rings intercept light from the central star and re-radiate it in a way that we can detect it on Earth. One way to discover stars that are forming new planets is to look for these dusty rings.

"That was the seed of the idea; if we took a small amount of material and put it on a special orbit between the Earth and the sun and broke it up, we could block out a lot of sunlight with a little amount of mass," said Ben Bromley, professor of physics and astronomy and lead author of the study.

"It is amazing to contemplate how moon dust -- which took over four billion years to generate -- might help slow the rise in Earth's temperature, a problem that took us less than 300 years to produce," said Scott Kenyon, co-author of the study from the Center for Astrophysics | Harvard & Smithsonian.

The paper was published on Wednesday, Feb. 8, 2023, in the journal PLOS Climate.

Casting a shadow

A shield's overall effectiveness depends on its ability to sustain an orbit that casts a shadow on Earth. Sameer Khan, undergraduate student and the study's co-author, led the initial exploration into which orbits could hold dust in position long enough to provide adequate shading. Khan's work demonstrated the difficulty of keeping dust where you need it to be.

"Because we know the positions and masses of the major celestial bodies in our solar system, we can simply use the laws of gravity to track the position of a simulated sunshield over time for several different orbits," said Khan.

Two scenarios were promising. In the first scenario, the authors positioned a space platform at the L1 Lagrange point, the closest point between Earth and the sun where the gravitational forces are balanced. Objects at Lagrange points tend to stay along a path between the two celestial bodies, which is why the James Webb Space Telescope (JWST) is located at L2, a Lagrange point on the opposite side of the Earth.

In computer simulations, the researchers shot test particles along the L1 orbit, including the position of Earth, the sun, the moon, and other solar system planets, and tracked where the particles scattered. The authors found that when launched precisely, the dust would follow a path between Earth and the sun, effectively creating shade, at least for a while. Unlike the 13,000-pound JWST, the dust was easily blown off course by the solar winds, radiation, and gravity within the solar system. Any L1 platform would need to create an endless supply of new dust batches to blast into orbit every few days after the initial spray dissipates.

"It was rather difficult to get the shield to stay at L1 long enough to cast a meaningful shadow. This shouldn't come as a surprise, though, since L1 is an unstable equilibrium point. Even the slightest deviation in the sunshield's orbit can cause it to rapidly drift out of place, so our simulations had to be extremely precise," Khan said.

In the second scenario, the authors shot lunar dust from the surface of the moon towards the sun. They found that the inherent properties of lunar dust were just right to effectively work as a sun shield. The simulations tested how lunar dust scattered along various courses until they found excellent trajectories aimed toward L1 that served as an effective sun shield. These results are welcome news, because much less energy is needed to launch dust from the moon than from Earth. This is important because the amount of dust in a solar shield is large, comparable to the output of a big mining operation here on Earth. Furthermore, the discovery of the new sun-shielding trajectories means delivering the lunar dust to a separate platform at L1 may not be necessary.

Just a moonshot?

The authors stress that this study only explores the potential impact of this strategy, rather than evaluate whether these scenarios are logistically feasible.

"We aren't experts in climate change, or the rocket science needed to move mass from one place to the other. We're just exploring different kinds of dust on a variety of orbits to see how effective this approach might be. We do not want to miss a game changer for such a critical problem," said Bromley.

One of the biggest logistical challenges -- replenishing dust streams every few days -- also has an advantage. Eventually, the sun's radiation disperses the dust particles throughout the solar system; the sun shield is temporary and shield particles do not fall onto Earth. The authors assure that their approach would not create a permanently cold, uninhabitable planet, as in the science fiction story, "Snowpiercer."

Read more at Science Daily

'We're not all that different': Study IDs bacterial weapons that could be harnessed to treat human disease

When it comes to fighting off invaders, bacteria operate in a remarkably similar way to human cells, possessing the same core machinery required to switch immune pathways on and off, according to new University of Colorado Boulder research.

The study, published Feb. 8 in the journal Nature, also sheds light on how that shared, ancient machinery -- a cluster of enzymes known as ubiquitin transferases -- works.

Better understanding, and potentially reprogramming this machine, could ultimately pave the way to novel approaches for treating a host of human diseases, from autoimmune disorders like Rheumatoid arthritis and Crohn's disease to neurodegenerative diseases like Parkinson's disease, the authors said.

"This study demonstrates that we're not all that different from bacteria," said senior author Aaron Whiteley, an assistant professor in the Department of Biochemistry. "We can learn a lot about how the human body works by studying these bacterial processes."

The next CRISPR?

The study is not the first to showcase the lessons bacteria can teach humans.

Mounting evidence suggests that portions of the human immune system may have originated in bacteria, with evolution yielding more complex iterations of bacterial virus-fighting tools across plant and animal kingdoms.

In 2020, University of California Berkeley biochemist Jennifer Doudna won the Nobel Prize for CRISPR, a gene-editing tool that repurposes another obscure system bacteria use to fight off their own viruses, known as phages.

The buzz around CRISPR ignited renewed scientific interest in the role proteins and enzymes play in anti-phage immune response.

"Over the past three to five years people have realized it doesn't end with CRISPR. The potential is so much bigger," said Whiteley.

Missing link in evolutionary history

For the study, Whiteley and co-first author Hannah Ledvina, a Jane Coffin Childs Postdoctoral Fellow in the department, collaborated with University of California San Diego biochemists to learn more about a protein called cGAS (cyclic GMP-AMP synthase), previously shown to be present in both humans and, in a simpler form, bacteria.

In bacteria and in humans, cGAS is critical for mounting a downstream defense when the cell senses a viral invader. But what regulates this process in bacteria was previously unknown.

Using an ultra-high-resolution technique called cryo-electron microscopy alongside other genetic and biochemical experiments, Whiteley's team took an up-close look at the structure of cGAS's evolutionary predecessor in bacteria and discovered additional proteins that bacteria use to help cGAS defend the cell from viral attack.

Specifically, they discovered that bacteria modify their cGAS using a streamlined "all-in-one version" of ubiquitin transferase, a complex collection of enzymes that in humans control immune signaling and other critical cellular processes.

Because bacteria are easier to genetically manipulate and study than human cells, this discovery opens a new world of opportunity for research, said Ledvina.

"The ubiquitin transferases in bacteria are a missing link in our understanding of the evolutionary history of these proteins."

Editing proteins

The study also revealed just how this machine works, identifying two key components -- proteins called Cap2 and Cap3 (CD-NTase-associated protein 2 and 3) -- which serve, respectively, as on and off switches for the cGAS response.

Whiteley explained that in addition to playing a key role in immune response, ubiquitin in humans can serve as a sort of marker for cellular garbage, directing excess or old proteins to be broken down and destroyed. When that system misfires due to mutations in the machine, proteins can build up and diseases, such as Parkinson's, can occur.

The authors stress that far more research is needed but the discovery opens exciting scientific doors. Just as scientists adapted the ancient bacterial defense system CRISPR into scissor-like biotechnology that can snip mutations out of DNA, Whiteley believes pieces of the bacterial ubiquitin transferase machine -- namely Cap3, the "off switch" -- could ultimately be programmed to edit out problem proteins and treat disease in humans.

He and his team, with the help of Venture Partners at CU Boulder, have already filed for intellectual property protection, and they're moving forward with more research.

Read more at Science Daily

HETDEX reveals galaxy gold mine in first large survey

Astronomers have barely scratched the surface of mapping the nearly endless stars and galaxies of the heavens. Using supercomputers, researchers with The University of Texas at Austin have has now revealed the locations of more than 200,000 new astronomical objects. Their goal is to map even more and use that knowledge to predict the ultimate fate of the universe.

The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) has scanned the dark skies of the Davis Mountains in West Texas since 2017 with a keen eye towards capturing spectroscopic data on Lyman-alpha frequency light from neutral hydrogen emission in galaxies over 10 billion light years away. These galaxies emit a signature wavelength of light from hydrogen that signals to astronomers the intense creation of new stars.

The HETDEX collaboration involves a large team including astronomers, engineers, technicians, and graduate students from six academic institutions in the United States and Germany.

For the first time, the researchers have cataloged astronomical objects -- mapping over 51,863 Lyman-alpha-emitting galaxies at high redshift; 123,891 star forming galaxies at lower redshift; 5,274 non-emission line galaxies at low redshift; and 4,976 active galactic nuclei (AGN) -- bright spots that signal the presence of black holes.

The paper describing the catalog is published February 2023 in The Astrophysical Journal.

"We've just exploded in terms of the number of redshifts cataloged for the first time," said study co-author Erin Mentuch Cooper, a research scientist at The University of Texas at Austin (UT Austin). Cooper is the data manager for the HETDEX project.

"There is a gold mine of astronomy exploration in the HETDEX catalog. That's what I love about it," said study co-author Karl Gebhardt, the Herman and Joan Suit Professor in Astronomy, College of Natural Sciences, UT Austin. Gebhardt is project scientist and principal investigator of HETDEX.

A star's redshift tells astronomers how fast a star is moving away from the Earth because its frequency, akin to its color, gets lower as it moves away, much like the horn of a train as it passes by.

The faster a star moves away, the farther away it is. That relationship between speed and distance, called Hubble's Law, can pin down a galaxy's location and allows astronomers to create a 3D map of over 200,000 stars and galaxies with HETDEX.

"This is only a small percentage of what we will find, but it's a good start. Ultimately, HETDEX aims to map one million red-shifted galaxies," Cooper said.

HETDEX is unique from previous large sky surveys because it's a non-targeted survey, blanketing the sky and collecting spectra from the 35,000 fiber optic cables of the Visible Integral Field Replicable Unit Spectrograph (VIRUS).

VIRUS takes starlight from distant galaxies and splits the light into its component colors like a prism does. HETDEX tiles the sky, collecting 35,000 spectra in a moon-sized swath of sky and moving from spot to spot. It collects about 500-600 hours of observations each year for its survey data.

"We have the largest spectroscopic instrument on the planet, and we're doing one of the longest surveys in terms of time," Gebhardt said. "To analyze this data, we need the fastest computer we can get our hands on, and that's where TACC comes in. TACC does all the data storage and all the data analysis for this giant survey."

The data from the telescope goes straight to the TACC Corral data storage system via high speed lines at 100 Gigabits/second.

"TACC has worked hard with us to streamline our system, and it's just working fantastically. We can process years of data in a couple of days, maybe a week of time on TACC systems. And we do it multiple times because we keep adjusting and improving our methods," Gebhardt added.

HETDEX used the Maverick and Stampede2 supercomputers of the Texas Advanced Computing Center, a leading academic supercomputing center at UT Austin. Stampede2 is funded by the National Science Foundation as a shared resource for thousands of scientists across the US. They helped process and analyze about 60 terabytes of image data on TACC's Corral system.

What's more, Cooper and colleagues have worked with TACC to create JupyterHub public access to the data.

"Anyone with any academic credentials can get a TACC account and go on through a web browser to access our data. We're going to let them access all of our data. This is just the catalog right now. But, the future is going to offer a legacy potential of the science from HETDEX. TACC is helping setting that up," Cooper said.

One interesting highlight from the catalog is the identification of an active galactic nuclei (AGN) with strong Lyman-alpha light emission. Gebhadt co-authored a studyled by UT Austin astronomy post-doctoral researcher Chenxu Liu, published November 2022 in The Astrophysical Journal. It presents intriguing evidence of a black hole without a surrounding host galaxy.

"This is what I call 'naked black holes,'" Gebhardt said. "Nothing confirmed yet, but we suspect these could be out there. Only a survey like HETDEX will be able to find these."

The science generated from HETDEX adds to the bigger picture of understanding the expansion of the entire universe, unexpectedly growing much faster than expected based on precise observations from the Hubble Space Telescope in 2019 of supernovae that act like a cosmic yardstick.

The Holy Grail for HETDEX is an accurate measure of the Universe expansion rate 10 billion years ago that will reveal the physical model for dark energy.

Astronomers are at odds over how to explain the measure of the current expansion rate. Understanding it could require a modification in the theory of gravity, or a change in the fundamental Big Bang theory. It might be the handiwork of an undiscovered particle.

A precise value of the expansion rate early in the Universe can be compared to the expansion rate today. This comparison can determine if the Universe will continue to expand forever, or will someday collapse on itself many billions of years from now.

"The whole point of the HETDEX project is to measure the expansion of the universe," Gebhardt said.

Read more at Science Daily

Fossil discovery reveals complex ecosystems existed on Earth much earlier than previously thought

About 250 million years ago, the Permian-Triassic mass extinction killed over 80 per cent of the planet's species. In the aftermath, scientists believe that life on earth was dominated by simple species for up to 10 million years before more complex ecosystems could evolve. Now this longstanding theory is being challenged by a team of international researchers -- including scientists from McGill University and Université du Québec à Montréal.

A fossilized ocean ecosystem

Until now, scientists have long theorized that scorching hot ocean conditions resulting from catastrophic climate change prevented the development of complex life after the mass extinction. This idea is based on geochemical evidence of ocean conditions at the time. Now the discovery of fossils dating back 250.8 million years near the Guizhou region of China suggests that complex ecosystems were present on Earth just one million years after the Permian-Triassic mass extinction, which is much earlier than previously thought.

"The fossils of the Guizhou region reveal an ocean ecosystem with diverse species making up a complex food chain that includes plant life, boney fish, ray-finned fish, crabs, lobsters, shrimp, and molluscs. In all, our team discovered 12 classes of organisms and even found fossilised faeces, revealing clues about the diets of these ancient animals," says Morgann Perrot, a former postdoctoral researcher at McGill University, now at Université du Québec à Montréal.

Challenging an age-old theory

Previously, it was thought that complex ecosystem would need five to ten million years to evolve after an extinction. However, the researchers found that the specimens in the Guizhou region evolved much quicker than that by using radiometric dating to date the rocks where the fossils were discovered.

"All of this has implications for our understanding of how quickly life can respond to extreme crises. It also necessitates a re-evaluation of early Triassic ocean conditions," says Perrot, whose research focuses on earth sciences and geochronology.

From Science Daily

2.9-million-year-old butchery site reopens case of who made first stone tools

Along the shores of Africa's Lake Victoria in Kenya roughly 2.9 million years ago, early human ancestors used some of the oldest stone tools ever found to butcher hippos and pound plant material, according to new research led by scientists with the Smithsonian's National Museum of Natural History and Queens College, CUNY, as well as the National Museums of Kenya, Liverpool John Moores University and the Cleveland Museum of Natural History.

The study, published today, Feb. 9, in the journal Science, presents what are likely to be the oldest examples of a hugely important stone-age innovation known to scientists as the Oldowan toolkit, as well as the oldest evidence of hominins consuming very large animals. Though multiple lines of evidence suggest the artifacts are likely to be about 2.9 million years old, the artifacts can be more conservatively dated to between 2.6 and 3 million years old, said lead study author Thomas Plummer of Queens College, research associate in the scientific team of the Smithsonian's Human Origins Program.

Excavations at the site, named Nyayanga and located on the Homa Peninsula in western Kenya, also produced a pair of massive molars belonging to the human species' close evolutionary relative Paranthropus. The teeth are the oldest fossilized Paranthropus remains yet found, and their presence at a site loaded with stone tools raises intriguing questions about which human ancestor made those tools, said Rick Potts, senior author of the study and the National Museum of Natural History's Peter Buck Chair of Human Origins.

"The assumption among researchers has long been that only the genus Homo, to which humans belong, was capable of making stone tools," Potts said. "But finding Paranthropus alongside these stone tools opens up a fascinating whodunnit."

Whichever hominin lineage was responsible for the tools, they were found more than 800 miles from the previously known oldest examples of Oldowan stone tools -- 2.6-million-year-old tools unearthed in Ledi-Geraru, Ethiopia. This greatly expands the area associated with Oldowan technology's earliest origins. Further, the stone tools from the site in Ethiopia could not be tied to any particular function or use, leading to speculation about what the Oldowan toolkit's earliest uses might have been.

Through analysis of the wear patterns on the stone tools and animal bones discovered at Nyayanga, Kenya, the team behind this latest discovery shows that these stone tools were used by early human ancestors to process a wide range of materials and foods, including plants, meat and even bone marrow.

The Oldowan toolkit includes three types of stone tools: hammerstones, cores and flakes. Hammerstones can be used for hitting other rocks to create tools or for pounding other materials. Cores typically have an angular or oval shape, and when struck at an angle with a hammerstone, the core splits off a piece, or flake, that can be used as a cutting or scraping edge or further refined using a hammerstone.

"With these tools you can crush better than an elephant's molar can and cut better than a lion's canine can," Potts said. "Oldowan technology was like suddenly evolving a brand-new set of teeth outside your body, and it opened up a new variety of foods on the African savannah to our ancestors."

Potts and Plummer were first drawn to the Homa Peninsula in Kenya by reports of large numbers of fossilized baboon-like monkeys named Theropithecus oswaldi, which are often found alongside evidence of human ancestors. After many visits to the peninsula, a local man named Peter Onyango working with the team suggested they check out fossils and stone tools eroding from a nearby site that was ultimately named Nyayanga after an adjacent beach.

Beginning in 2015, a series of excavations at Nyayanga returned a trove of 330 artifacts, 1,776 animal bones and the two hominin molars identified as belonging to Paranthropus. The artifacts, Plummer said, were clearly part of the stone-age technological breakthrough that was the Oldowan toolkit.

Compared to the only other stone tools known to have preceded them -- a set of 3.3-million-year-old artifacts unearthed at a site called Lomekwi 3, just west of Lake Turkana in Kenya -- Oldowan tools were a significant upgrade in sophistication. Oldowan tools were systematically produced and often fashioned using what is known as "freehand percussion," meaning the core was held in one hand and then struck with a hammerstone being wielded by the opposing hand at just the right angle to produce a flake -- a technique that requires significant dexterity and skill.

By contrast, most of the artifacts from Lomekwi 3 were created by using large stationary rocks as anvils, with the toolmaker either banging a core against the flat anvil stone to create flakes or by setting the core down on the anvil and striking it with a hammerstone. These more rudimentary modes of fabrication resulted in larger, cruder and more haphazard-looking tools.

Over time, the Oldowan toolkit spread all the way across Africa and even as far as modern-day Georgia and China, and it was not meaningfully replaced or amended until some 1.7 million years ago when the hand-axes of the Acheulean first appeared.

As part of their study, the researchers conducted microscopic analysis of wear patterns on the stone tools to determine how they were used, and they examined any bones seen to exhibit potential cut marks or other kinds of damage that might have come from stone tools.

The site featured at least three individual hippos. Two of these incomplete skeletons included bones that showed signs of butchery. The team found a deep cut mark on one hippo's rib fragment and a series of four short, parallel cuts on the shin bone of another. Plummer said they also found antelope bones that showed evidence of hominins slicing away flesh with stone flakes or of having been crushed by hammerstones to extract marrow.

The analysis of wear patterns on 30 of the stone tools found at the site showed that they had been used to cut, scrape and pound both animals and plants. Because fire would not be harnessed by hominins for another 2 million years or so, these stone toolmakers would have eaten everything raw, perhaps pounding the meat into something like a hippo tartare to make it easier to chew.

Using a combination of dating techniques, including the rate of decay of radioactive elements, reversals of Earth's magnetic field and the presence of certain fossil animals whose timing in the fossil record is well established, the research team was able to date the items recovered from Nyayanga to between 2.58 and 3 million years old.

"This is one of the oldest if not the oldest example of Oldowan technology," Plummer said. "This shows the toolkit was more widely distributed at an earlier date than people realized, and that it was used to process a wide variety of plant and animal tissues. We don't know for sure what the adaptive significance was but the variety of uses suggests it was important to these hominins."

The discovery of teeth from the muscular-jawed Paranthropus alongside these stone tools begs the question of whether it might have been that lineage rather than the Homo genus that was the architect of the earliest Oldowan stone tools, or perhaps even that multiple lineages were making these tools at roughly the same time.

The excavations behind this study offer a snapshot of the world humans' ancestors inhabited and help illustrate the ways that stone technology allowed these early hominins to adapt to different environments and, ultimately, give rise to the human species.

"East Africa wasn't a stable cradle for our species' ancestors," Potts said. "It was more of a boiling cauldron of environmental change, with downpours and droughts and a diverse, ever-changing menu of foods. Oldowan stone tools could have cut and pounded through it all and helped early toolmakers adapt to new places and new opportunities, whether it's a dead hippo or a starchy root."

Read more at Science Daily

Cockatoos know to bring along multiple tools when they fish for cashews

Goffin's cockatoos have been added to the short list of non-human animals that use and transport toolsets. In a study publishing in the journal Current Biology on February 10, researchers show that the cockatoos carry multiple tools to their worksite when the job calls for it. This behavior has only been previously reported in chimpanzees, our closest relatives.

Goffin's cockatoos are small white parrots that hail from the Tanimbar Islands archipelago in Indonesia. Captive Goffin's cockatoos use and manufacture tools, and a recent study of wild-caught cockatoos reported that they can use up to three different tools to extract seeds from a particular fruit. Up until now, though, it wasn't clear whether the cockatoos considered these tools as a "set"; it's possible that what may look like a toolset is instead nothing more than a chain of single tool uses, with the need for each new tool appearing to the animal as the task evolves.

Now, a team of researchers have used controlled experiments to clarify that the cockatoos do indeed recognize when a job requires more than one tool. "With this experiment we can say that, like chimpanzees, Goffin's cockatoos not only appear to be to using toolsets, but they know that they are using toolsets," says first author Antonio Osuna-Mascaró, an evolutionary biologist at the University of Veterinary Medicine Vienna. "Their flexibility of behavior is stunning."

Osuna-Mascaró was inspired by the termite-fishing Goualougo Triangle chimpanzees of northern Congo, the only other known non-human animal to use toolsets. These chimpanzees fish for termites via a two-step process: first, they use a blunt stick to break holes in the termite mound, and then they insert a long, flexible probe to "fish" the termites out of the holes. In this study, Osuna-Mascaró's team tasked the cockatoos with fishing for cashews instead of termites.

To mimic the termite-fishing set-up, the researchers presented the cockatoos with a box containing a cashew behind a transparent paper membrane. To reach the cashew, the cockatoos had to punch through the membrane and then "fish" the cashew out. They were provided with a short, pointy stick for punching holes and a vertically halved plastic straw for fishing.

Seven of the ten cockatoos tested taught themselves to extract cashews successfully by punching through the membrane, and two of the cockatoos (Figaro and Fini) completed the task within 35 seconds on their first attempt. The cockatoos don't have an equivalent foraging behavior in the wild, so there was no chance that their tool use was based on innate behaviors, and each cockatoo used a slightly different technique.

Next, the team tested the cockatoos' ability to change their tool use in a flexible manner depending on the situation. To do this, they presented each cockatoo with two different types of box: one with a membrane and one without. The cockatoos were given the same two tools, but they only needed the pointy stick when a membrane was in the way. "The cockatoos had to act according to the problem; sometimes the toolset was needed, and sometimes only one tool was enough," says Osuna-Mascaró.

All of the cockatoos mastered the test in a very short period of time and were able to recognize when a single tool was sufficient. However, the birds engaged in an interesting behavior during this choosing phase. "When making the choice between which tool to use first, they were picking one up, releasing it, then picking up the other one, releasing it, returning to the first one, and so on," says Osuna-Mascaró. The researchers found that when cockatoos did this switching, they performed better on the tests.

Next, the team tested the cockatoos' ability to transport the tools as a set on an as-needed basis. They put the cockatoos through a series of increasingly challenging trials to reach the boxes: first they had to climb a short ladder while carrying their tools; then they had to fly horizontally with them; and in the final test, they had to carry the tools while flying vertically. As before, the birds were only sometimes presented with a box with a membrane barrier, so they had to decide whether the problem required one or both tools.

Some cockatoos learned to carry the two tools together -- by inserting the short punching stick into the groove of the halved straw -- when they were presented with a box that required both. This meant they only had to make one trip, albeit while carrying a heavier toolset. Most of the cockatoos transported the toolset on an as-needed basis, further indicating that they knew ahead of time when two tools were required, though some made two trips when necessary. One cockatoo, Figaro, decided not to waste time thinking and instead carried both tools in almost every trial.

"We really did not know whether the cockatoos would transport two objects together," says Alice Auersperg, senior author on the study and a cognitive biologist at the University of Veterinary Medicine Vienna. "It was a little bit of a gamble because I have seen birds combining objects playfully, but they very rarely transport more than one object together in their normal behavior."

There's a lot more to be learned about cockatoo tool use, the researchers say. "We feel that, in terms of technical cognition and tool use, parrots have been underestimated and understudied," says Auersperg.

Read more at Science Daily

Hubble captures the start of a new spoke season at Saturn

New images of Saturn from NASA's Hubble Space Telescope herald the start of the planet's "spoke season" surrounding its equinox, when enigmatic features appear across its rings. The cause of the spokes, as well as their seasonal variability, has yet to be fully explained by planetary scientists.

Like Earth, Saturn is tilted on its axis and therefore has four seasons, though because of Saturn's much larger orbit, each season lasts approximately seven Earth years. Equinox occurs when the rings are tilted edge-on to the Sun. The spokes disappear when it is near summer or winter solstice on Saturn. (When the Sun appears to reach either its highest or lowest latitude in the northern or southern hemisphere of a planet.) As the autumnal equinox of Saturn's northern hemisphere on May 6, 2025, draws near, the spokes are expected to become increasingly prominent and observable.

The suspected culprit for the spokes is the planet's variable magnetic field. Planetary magnetic fields interact with the solar wind, creating an electrically charged environment (on Earth, when those charged particles hit the atmosphere this is visible in the northern hemisphere as the aurora borealis, or northern lights). Scientists think that the smallest, dust-sized icy ring particles can become charged as well, which temporarily levitates those particles above the rest of the larger icy particles and boulders in the rings.

The ring spokes were first observed by NASA's Voyager mission in the early 1980s. The transient, mysterious features can appear dark or light depending on the illumination and viewing angles.

"Thanks to Hubble's OPAL program, which is building an archive of data on the outer solar system planets, we will have longer dedicated time to study Saturn's spokes this season than ever before," said NASA senior planetary scientist Amy Simon, head of the Hubble Outer Planet Atmospheres Legacy (OPAL) program.

Saturn's last equinox occurred in 2009, while NASA's Cassini spacecraft was orbiting the gas giant planet for close-up reconnaissance. With Cassini's mission completed in 2017, and the Voyager spacecrafts long gone, Hubble is continuing the work of long-term monitoring of changes on Saturn and the other outer planets.

"Despite years of excellent observations by the Cassini mission, the precise beginning and duration of the spoke season is still unpredictable, rather like predicting the first storm during hurricane season," Simon said.

While our solar system's other three gas giant planets also have ring systems, nothing compares to Saturn's prominent rings, making them a laboratory for studying spoke phenomena. Whether spokes could or do occur at other ringed planets is currently unknown. "It's a fascinating magic trick of nature we only see on Saturn -- for now at least," Simon said.

Hubble's OPAL program will add both visual and spectroscopic data, in wavelengths of light from ultraviolet to near-infrared, to the archive of Cassini observations. Scientists are anticipating putting these pieces together to get a more complete picture of the spoke phenomenon, and what it reveals about ring physics in general.

Read more at Science Daily

Global wetlands losses overestimated despite high losses in many regions

Sometime this spring or summer, the Supreme Court is expected to issue a case ruling that will legally define whether federal protections should be extended to wetlands outside of navigable waters. The justices might consider reading a new Stanford-led study that finds, although wetlands remain threatened in many parts of the world -- including the U.S., which accounts for more losses than any other country -- global losses of wetlands have likely been overestimated. Published Feb. 8 in Nature, the study's findings could help better explain the causes and impacts of wetland loss, enabling more informed plans to protect or restore ecosystems crucial for human health and livelihoods.

"Despite the good news that our results might imply, it remains urgent to halt and reverse the conversion and degradation of wetlands," said study lead author Etienne Fluet-Chouinard, a postdoctoral associate in Stanford's Department of Earth System Science at the time of the research. "The geographic disparities in losses are critical to consider because the forgone local benefits from drained wetlands cannot be replaced by wetlands elsewhere."

Rethinking wetlands

Now understood to be vital sources of water purification, groundwater recharge, and carbon storage, wetlands were long seen as unproductive areas teeming with disease-bearing insects and good only for draining to grow crops or harvest peat for fuel and fertilizer. Unrelenting drainage for conversion to human land uses, such as farmland and urban areas, in addition to alteration by fires and groundwater extraction, has made wetlands among the world's most threatened ecosystems in the world.

Accurately estimating the extent, distribution, and timing of wetland loss is key to understanding their role in natural processes and the impact of wetland drainage on the water and carbon cycles. A lack of historical data has hindered the effort, forcing scientists to make estimates based on incomplete collections of regional data on wetland loss.

"Wetlands purify our water, prevent flooding, and are biodiversity superheroes," said study co-author Rob Jackson, the Michelle and Kevin Douglas Provostial Professor of Energy and Environment in the Stanford Doerr School of Sustainability. "We need the best data possible to save what we have and know what we've lost."

A second chance

In a first-of-its-kind historical reconstruction, the researchers combed through thousands of records of wetland drainage and land-use changes in 154 countries, mapping the distribution of drained and converted wetlands onto maps of present-day wetlands to get a picture of what the original wetland area might have looked like in 1700.

They found that the area of wetland ecosystems has declined 21-35% since 1700 due to human intervention. That's far less than the 50-87% losses estimated by previous studies. Still, the authors estimate that at least 1.3 million square miles of wetlands have been lost globally -- an area about the size of Alaska, Texas, California, Montana, New Mexico, and Arizona combined.

"These new results allow us to better quantify changes in wetlands' sequestration of carbon from the atmosphere and emission of methane, another powerful greenhouse gas," said study co-author Avni Malhotra, a Stanford postdoctoral researcher at the time of the research.

The low estimate is likely the result of the study's focus beyond regions with historically high wetland losses, and its avoidance of large extrapolations -- characteristics of many previous estimates. The researchers note their estimate of losses is likely conservative because they constrained their analysis to available data, which is scarce for the years before 1850.

Despite what may seem to be good news, the researchers emphasize that wetland losses have been dramatically high in some regions, such as the U.S., which is estimated to have lost 40% of its wetlands since 1700 and accounts for more than 15% of all global losses during the study's time period. Although wetland conversion and degradation have slowed globally, it continues apace in some regions, such as Indonesia, where farmers and corporations continue to clear large swaths of land for oil palm plantations and other agricultural uses.

Read more at Science Daily

How giants became dwarfs

Difference in body size (or sexual dimorphism) between males and females is common across the animal kingdom. One of the most extreme examples of sexual dimorphism is found in the cichlid fish species Lamprologous callipterus from Lake Tanganyika in East Africa, where males are 12 times bigger (heavier) than females. The ecological reason for this remarkable size difference is the fact that this species uses empty snail shells found at the bottom of the lake to build nests. Hence males must be large enough to carry shells with their mouths, whereas females need to be small enough to fit inside the snail shells to lay eggs, where they are well protected from predators. Sex-specific differences in body size are important for the biology of this species, as small males would not be able to carry empty snail shells and large females would not be able to enter the shells for breeding.

The most peculiar feature of this species, however, is the existence of a second male morph, which is 60 times smaller (lighter) than the nest-building giants. These small fellows sneak into the shells when a female is spawning, only to fertilise there the freshly laid eggs. It had been shown already that the giant nest males and the dwarf parasites only sire sons developing into the same male type as their father. In a new study published in Molecular Ecology, Pooja Singh, formerly from the University of Graz, Michael Taborsky und Catherine Peichel, all of whom are now located at the Institute of Ecology and Evolution (IEE) of the University of Bern, and Christian Sturmbauer from the University of Graz, unravelled how the alternative sizes and different sexes are determined in these cichlids.

The genetic mechanism underlying this unique reproductive system

Genomic analyses revealed a Y sex chromosome region differing between males and females. "This was a first important step, because these cichlids lack the highly differentiated sex chromosomes we know from humans and many other animals," says Pooja Singh, first author of this publication. This was exactly the worthwhile challenge, because thereby the early stages of sex chromosome evolution could be reconstructed in connection with a size-determining genetic mechanism that appeared to be influenced by intra- and intersexual conflict.

The researchers found that this small y-like genomic region contained also the growth hormone regulator gene GHRHR, which was intriguing. "This gene is known to serve an important regulatory function for growth in mammals, and mutations of this gene may lead to dwarfism also in humans," explains co-author Katie Peichel. As this gene has been identified now also in fishes, it has probably emerged more than 440 million years ago, before aquatic vertebrates conquered terrestrial domains. In the studied snail shell brooding cichlids this size regulating gene has apparently evolved in conjunction with the sex-determining genetic loci.

Who came first, giant or dwarf?

The different reproductive roles of males and females, and of males belonging either to the nest-building or the parasitic type, suggest conflicting selective pressures yielding reproductive success dependent on body size. Concerning the male size-dimorphism, it is interesting to ponder over the most likely chronological order. Co-author Michael Taborsky proposes that giants preceded dwarfs: "The entire reproductive system of this species depends on the essential nest-building activity of giant males, who must be large enough to collect empty snail shells. The dwarf morph could then originate by a respective point mutation in the sex and size determining region of the genome, leading to a highly successful alternative reproductive tactic."

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Scientists develop new index based on functional morphology to understand how ancestors of modern birds used their wings

Scientists at Nagoya University in Japan have developed an index to estimate how a bird uses its wings for flight or other locomotion by measuring the strength of the coracoid bone and the animal's body mass. It should improve our understanding of how extinct animals used their wings and the different patterns of wing-propelled locomotion that emerged as birds evolved. Their findings were published in the Journal of Anatomy.

The presence of a wing alone does not tell us whether an animal can fly. For example, penguins evolved wings to propel them through water whereas feathered dinosaurs may have used their wings for other purposes, such as thermoregulation and intraspecific display. Therefore, to better understand how animals evolved the ability to fly, an index must take into account both the presence of wings and the ability to perform powerful wing-beats.

"We wanted to create a new index because people think that if an animal has wings, then it can fly," said the study's second author, Assistant Professor Shin-ichi Fujiwara. "But this is not always true. An animal can also use its wings for other purposes, such as thermal insulation in flightless animals. Our research team focused on how changes in skeletal morphology can lead to changes in locomotion. Subsequently, these changes can lead to major ecological transitions such as a shift in lifestyle from a terrestrial environment to an aerial, aquatic, arboreal, or subterranean environment. The origin of flight in birds has been an important topic in this field. We, therefore, needed to develop an alternative index, based on biomechanics, to determine the flapping ability of birds and which we could also use to measure skeletal remains."

To create this index, the researchers used the avian coracoid bone. The coracoid bone acts as a strut to prevent the thoracic skeleton from deforming when an animal's powerful flight muscles, which connect the wings to the sternum, contract. Doctoral student Takumi Akeda of the Department of Earth and Planetary Sciences, Graduate School of Environmental Studies, at Nagoya University, and Fujiwara of the Nagoya University Museum, measured the size of a cross section of the coracoid bone in relation to the body mass of 220 bird specimens. Their sample of 209 species included extinct birds such as the dodo and the great auk.

The researchers then divided the birds into four groups based on how they used their wings. These groups were those that used flapping flight (e.g., pigeons); those that used wing-propelled diving (e.g., penguins); those that were flightless with no flapping ability (e.g., ostriches); and those that used thermal and dynamic soaring (e.g., albatrosses and vultures). Based on the strength of the coracoid bone and flapping ability, the researchers could create a new index to analyze flight patterns.

They found that the strength of the coracoid in relation to body mass may reflect the force exerted by the flight muscles, which counteract the lifting force on the wings. This helps to estimate how a bird uses propulsion. Soaring birds had increased coracoid strength, probably to enable them to withstand the greater bending forces caused by the contraction of the flapping muscles. In contrast, non-flapping birds had lower coracoid strength. These findings show that coracoid strength in relation to body mass reflects the lifting force on the wings, therefore, it is a useful tool for reconstructing the type of propulsion used by the animal.

Akeda and Fujiwara's index should allow future researchers to assess the flight styles and flapping abilities of not only extinct birds but also other flying animals, including the Pteranodon and Quetzalcoatlus of "Jurassic World" fame. The index could also allow them to estimate the origin of flight in winged theropods, the ancestors of birds.

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A new ring system discovered in our Solar System

Scientists have discovered a new ring system around a dwarf planet on the edge of the Solar System. The ring system orbits much further out than is typical for other ring systems, calling into question current theories of how ring systems are formed.

The ring system is around a dwarf planet, named Quaoar, which is approximately half the size of Pluto and orbits the Sun beyond Neptune.

The discovery, published in Nature, was made by an international team of astronomers using HiPERCAM -- an extremely sensitive high-speed camera developed by scientists at the University of Sheffield which is mounted on the world's largest optical telescope, the 10.4 metre diameter Gran Telescopio Canarias (GTC) on La Palma.

The rings are too small and faint to see directly in an image. Instead, the researchers made their discovery by observing an occultation, when the light from a background star was blocked by Quaoar as it orbits the Sun. The event lasted less than a minute, but was unexpectedly preceded and followed by two dips in light, indicative of a ring system around Quaoar.

Ring systems are relatively rare in the Solar System -- as well as the well-known rings around the giant planets Saturn, Jupiter, Uranus and Neptune, only two other minor planets possess rings -- Chariklo and Haumea. All of the previously known ring systems are able to survive because they orbit close to the parent body, so that tidal forces prevent the ring material from accreting and forming moons.

What makes the ring system around Quaoar remarkable is that it lies at a distance of over seven planetary radii -- twice as far out as what was previously thought to be the maximum radius according to the so-called `Roche limit', which is the outer limit of where ring systems were thought to be able to survive. For comparison, the main rings around Saturn lie within three planetary radii. This discovery has therefore forced a rethink on theories of ring formation.

Professor Vik Dhillon, co-author of the study from the University of Sheffield's Department of Physics and Astronomy, said: "It was unexpected to discover this new ring system in our Solar System, and it was doubly unexpected to find the rings so far out from Quaoar, challenging our previous notions of how such rings form. The use of our high-speed camera -- HiPERCAM -- was key to this discovery as the event lasted less than one minute and the rings are too small and faint to see in a direct image.

"Everyone learns about Saturn's magnificent rings when they're a child, so hopefully this new finding will provide further insight into how they came to be."

Read more at Science Daily

Video game playing causes no harm to young children's cognitive abilities, study finds

Parents: It might be time to rethink your family's video-gaming rules.

New research findings challenge the fears parents have been hearing for years that children who spend hour after hour playing video games, or choose games of certain genres, would manifest unhealthy results in their cognitive ability.

"Our studies turned up no such links, regardless of how long the children played and what types of games they chose," said Jie Zhang, associate professor of curriculum and instruction at the University of Houston College of Education and a member of the research team. The work is published in the Journal of Media Psychology.

In reaching the conclusions, researchers examined the video gaming habits of 160 diverse urban public-school preteen students (70% from lower income households), which represents an age group less studied in previous research. Participating students reported playing video games an average of 2.5 hours daily, with the group's heaviest gamers putting in as much as 4.5 hours each day.

The team looked for association between the students' video game play and their performance on the standardized Cognitive Ability Test 7, known as CogAT, which evaluates verbal, quantitative and nonverbal/spatial skills. CogAT was chosen as a standard measure, in contrast to the teacher-reported grades or self-reported learning assessments that previous research projects have relied on.

"Overall, neither duration of play nor choice of video game genres had significant correlations with the CogAT measures. That result shows no direct linkage between video game playing and cognitive performance, despite what had been assumed," said May Jadalla, professor in the School of Teaching and Learning at Illinois State University and the study's principal investigator.

But the study revealed another side of the issue, too. Certain types of games described as helping children build healthy cognitive skills also presented no measurable effects, in spite of the games' marketing messages.

"The current study found results that are consistent with previous research showing that types of gameplay that seem to augment cognitive functions in young adults don't have the same impact in much younger children," said C. Shawn Green, professor in the Department of Psychology at the University of Wisconsin-Madison.

Does this mean the world can play on? Maybe, the research suggests. But the experts also caution that gaming time took the heaviest players' away from other, more productive activities -- homework, to be specific -- in a process psychologists call displacement. But even in those cases, the differences were slight between those participants and their peers' CogAT measures of cognitive abilities.

 Read more at Science Daily

Codebreakers crack secrets of Mary Queen of Scots' lost letters

Secret, coded letters penned by Mary Queen of Scots while she was imprisoned in England by her cousin Queen Elizabeth I have been uncovered by a multidisciplinary team of international codebreakers.

The contents of the letters were believed for centuries to have been lost. That was until George Lasry, a computer scientist and cryptographer, Norbert Biermann, a pianist and music professor, and Satoshi Tomokiyo who is a physicist and patents expert, stumbled upon them while searching the national library of France's -- Bibliothèque nationale de France's (BnF) -- online archives for enciphered documents.

The trio only discovered Mary was the author after solving her sophisticated cipher system. Their decipherment work of 57 letters, which is presented in the peer-reviewed journal Cryptologia, reveals approximately 50 new scripts previously unknown to historians.

These date from 1578 to 1584, a few years before her beheading on this very day 436 years ago -- 8th February, 1587.

Mary's correspondences expose fascinating insights into her captivity. Most are addressed to Michel de Castelnau de Mauvissière, the French ambassador to England. He was a supporter of Catholic Mary who was under the Earl of Shrewsbury's custody when she wrote them.

"Upon deciphering the letters, I was very, very puzzled and it kind of felt surreal," says lead author Lasry, who is also part of the multi-disciplinary DECRYPT Project -- involving several universities in Europe, with the goal of mapping, digitizing, transcribing, and deciphering historical ciphers.

"We have broken secret codes from kings and queens previously, and they're very interesting but with Mary Queen of Scots it was remarkable as we had so many unpublished letters deciphered and because she is so famous.

"This is a truly exciting discovery."

He added: "Together, the letters constitute a voluminous body of new primary material on Mary Stuart -- about 50,000 words in total, shedding new light on some of her years of captivity in England.

"Mary, Queen of Scots, has left an extensive corpus of letters held in various archives. There was prior evidence, however, that other letters from Mary Stuart were missing from those collections, such as those referenced in other sources but not found elsewhere.

"The letters we have deciphered … are most likely part of this lost secret correspondence."

One of the 16th century's most famous historical figures, Mary was first in line of succession to the English throne after her cousin Elizabeth.

Catholics considered Mary to be the legitimate sovereign and Elizabeth had her imprisoned for 19 years because she was seen as a threat. Mary was eventually executed aged 44 for her alleged part in a plot to kill Elizabeth.

During her time in captivity, Mary communicated with her associates and allies through extensive efforts to recruit messengers and to maintain secrecy.

The existence of a confidential communication channel between Mary and Castelnau is well-known to historians, and even to the English government at the time.

But Lasry and his fellow codebreakers provide new evidence that this exchange was already in place as early as May 1578 and active until at least mid-1584.

Using computerized and manual techniques, the study authors decoded the letters which show the challenges Mary faced maintaining links with the outside world, how the letters were carried and by whom.

Key themes referred to in Mary's correspondence include complaints about her poor health and captivity conditions, and her negotiations with Queen Elizabeth I for her release, which she believes are not conducted in good faith.

Her mistrust of Elizabeth's spymaster Sir Francis Walsingham is also apparent, as well as her animosity for Robert Dudley, Earl of Leicester and a favourite of Elizabeth. She also expresses her distress when her son James (future King James I of England) is abducted in August 1582, and her feeling they have been abandoned by France.

Writing in this Special Issue version of Cryptologia, Lasry and hisco-authors describe how they first came across the letters. Some were in a large set of unmarked documents in cipher and using the same set of graphical symbols.

The BnF catalogue listed them as from the first half of the 16th century, and related to Italian matters. However, the study authors say they 'quickly realised' -- after starting to crack the code -- they were written in French and 'had nothing to do with Italy'.

Their detective work revealed verbs and adverbs often in the feminine form, several mentions of captivity, and the name 'Walsingham' which arose the suspicion that they might be from Mary, Queen of Scots.

This fact was confirmed by comparing them with the plaintext of letters in Walsingham's papers in the British Library and through other methods. A search for similar letters in BnF collections uncovered 57 letters with the same cipher.

Commenting on the new paper, Mary Queen of Scots expert, John Guy, who wrote the 2004 biography of Mary Queen of Scots which led to a major Hollywood film, says this is the most significant find about Mary for a century.

"This discovery is a literary and historical sensation. Fabulous! This is the most important new find on Mary Queen of Scots for 100 years. I'd always wondered if de Castelnau's originals could turn up one day, buried in the Bibliotheque Nationale de France or perhaps somewhere else, unidentified because of the ciphering.

"And now they have."

Lasry and his co-authors suggest, too, that other enciphered letters from Mary which are known to have existed may still be missing. A physical inspection of documents, as well as online searches, are needed to uncover these, they add.

Read more at Science Daily

Caribou have been using same Arctic calving grounds for 3,000 years

Caribou have been using the same Arctic calving grounds for more than 3,000 years, according to a new study by the University of Cincinnati.

Female caribou shed their antlers within days of giving birth, leaving behind a record of their annual travels across Alaska and Canada's Yukon that persists on the cold tundra for hundreds or even thousands of years. Researchers recovered antlers that have sat undisturbed on the arctic tundra since the Bronze Age.

"To walk around the landscape and pick up something that's 3,000 years old is truly amazing," said Joshua Miller, an assistant professor of geosciences at the University of Cincinnati.

He has been leading summer expeditions to the Arctic National Wildlife Refuge since 2010, using rafts to navigate remote rivers to search for caribou antlers exposed on the tundra.

"We think about having to dig down into the soil to find that kind of ecological history, but on the Coastal Plain, the vegetation grows extremely slowly," Miller said. "Bones dropped by animals that lived dozens or even hundreds of generations in the past can provide really meaningful information."

The study demonstrates how important the area is for an animal that native Alaskans and Candians still depend on for sustenance, even as energy companies seek to exploit oil and gas resources in this protected area.

The Biden Administration in 2021 suspended drilling leases in the Arctic National Wildlife Refuge, the largest tract of undeveloped wilderness in the United States.

"We know this region of the Arctic National Wildlife Refuge has been an important area for caribou for millennia," Miller said. "That should give us pause on how we think about those landscapes."

The study was published in the journal Frontiers in Ecology and Evolution.

Barren ground caribou undertake nature's longest overland migration, traveling as far as 800 miles each year to reach their spring calving grounds in the Arctic National Wildlife Refuge and Canada's Ivvavik National Park. The largest herd in this area, named for the Porcupine River, numbers in the hundreds of thousands of animals.

Scientists think caribou use these areas because they have fewer predators and offer seasonal vegetation near places where they can avoid the worst of the mosquitoes.

"The mosquitoes are horrible," Miller said. "You get swarmed -- literally covered in them. They can do significant damage to a young calf."

Whatever the reason, the antlers they leave behind provide a physical record of their epic yearly travels that researchers can unlock through isotopic analysis.

Caribou antlers, like those of elk, deer and moose, are made of fast-growing bone that the animals shed each year and regrow the following year.

"It is amazing to think that the oldest of the antlers found in our study were growing approximately the same time Homer was penning 'the Iliad' and 'the Odyssey,'" study co-author Patrick Druckenmiller said.

He is director of the University of Alaska Museum and professor of the Department of Geology and Geophysics at the University of Alaska Fairbanks. Eric Wald from the U.S. Fish and Wildlife Service also co-authored the study.

The antler surveys in the vast expanse of the Arctic refuge require meticulous logistical planning, Miller said. Small planes deposit researchers and their gear deep in the interior, where they have to be watchful for grizzly and polar bears. They pilot rafts to the Beaufort Sea, conducting a grid search of suitable caribou habitat identified in advance using aerial photography.

"We search for antlers along old river terraces, walking back and forth, covering every inch of habitat to find those ancient treasures," Miller said.

While male caribou antlers span four feet and weigh more than 20 pounds, female caribou antlers are much smaller. The antlers contain nutrients such as phosphorus and calcium that are important to plants and animals.

The dropped antlers create "nutrient sinks," which could have a profound effect on the area's vegetation. Miller said the caribou's migration serves as a nutrient "conveyor belt" that might even draw caribou back to reap the benefits of this fertilizer in a reinforcement loop.

Caribou and other mammals are known to chew on dropped antlers for their valuable minerals. This could be an important dietary supplement for new caribou moms.

"We'd like to know to what degree this conveyor belt influences why caribou are going there in the first place," Miller said. The study was supported by the U.S. Fish and Wildlife Service, the National Geographic Society, the National Science Foundation, the Wildlife Society and the UC Office of Research.

Miller said the Arctic is warming faster than other parts of the globe. Parts of the Arctic that were once barren tundra are sprouting new spruce forests.

Read more at Science Daily

A star is born: Study reveals complex chemistry inside 'stellar nurseries'

An international team of researchers has uncovered what might be a critical step in the chemical evolution of molecules in cosmic "stellar nurseries." In these vast clouds of cold gas and dust in space, trillions of molecules swirl together over millions of years. The collapse of these interstellar clouds eventually gives rise to young stars and planets.

Like human bodies, stellar nurseries contain a lot of organic molecules, which are made up mostly of carbon and hydrogen atoms. The group's results, published Feb. 6 in the journal Nature Astronomy, reveal how certain large organic molecules may form inside these clouds. It's one tiny step in the eons-long chemical journey that carbon atoms undergo -- forming in the hearts of dying stars, then becoming part of planets, living organisms on Earth and perhaps beyond.

"In these cold molecular clouds, you're creating the first building blocks that will, in the end, form stars and planets," said Jordy Bouwman, research associate at the Laboratory for Atmospheric and Space Physics (LASP) and assistant professor in the Department of Chemistry at the University of Colorado Boulder.

For the new study, Bouwman and his colleagues took a deep dive into one stellar nursery in particular: the Taurus Molecular Cloud (TMC-1). This region sits in the constellation Taurus and is roughly 440 light years (more than 2 quadrillion miles) from Earth. This chemically complex environment is an example of what astronomers call an "accreting starless core." Its cloud has begun to collapse, but scientists haven't yet detected embryonic stars emerging inside it.

The team's findings hinge on a deceptively simple molecule called ortho-benzyne. Drawing on experiments on Earth and computer simulations, the researchers showed that this molecule can readily combine with others in space to form a wide range of larger organic molecules.

Small building blocks, in other words, become big building blocks.

And, Bouwman said, those reactions could be a sign that stellar nurseries are a lot more interesting than scientists give them credit for.

"We're only at the start of truly understanding how we go from these small building blocks to larger molecules," he said. "I think we'll find that this chemistry is so much more complex than we thought, even at the earliest stages of star formation."

Fateful observation

Bouwman is a cosmochemist, studying a field that blends chemistry and astronomy to understand the churning chemical reactions that happen deep in space.

On the surface, he said, cold molecular clouds might not seem like a hotbed of chemical activity. As their name suggests, these galactic primordial soups tend to be frigid, often hovering around -263 degrees Celsius (about -440 degrees Fahrenheit), just 10 degrees above absolute zero. Most reactions need at least a little bit of heat to get a kick-start.

But cold or not, complex chemistry seems to be happening in stellar nurseries. TMC-1, in particular, contains surprising concentrations of relatively large organic molecules with names like fulvenallene and 1- and 2-ethynylcyclopentadiene. Chemists call them "five-membered ring compounds" because they each contain a ring of carbon atoms shaped like a pentagon.

"Researchers kept detecting these molecules in TMC-1, but their origin was unclear," Bouwman said.

Now, he and his colleagues think they have an answer.

In 2021, researchers using the Yebes 40-metre Radiotelescope in Spain found an unexpected molecule hiding in the clouds of gas of TMC-1: ortho-benzyne. Bouwman explained that this small molecule, made up of a ring of six carbon atoms with four hydrogens, is one of the extroverts of the chemistry world. It easily interacts with a number of other molecules and doesn't require a lot of heat to do so.

"There's no barrier to reaction," Bouwman said. "That means that it has the potential to drive complex chemistry in cold environments."

Identifying the culprit

To find out what kind of complex chemistry was happening in TMC-1, Bouwman and his colleagues -- who hail from the United States, Germany, the Netherlands and Switzerland -- turned to a technique called "photoelectron photoion coincidence spectroscopy." The team used light generated by a giant facility called a synchrotron light source to identify the products of chemical reactions. They saw that ortho-benzyne and methyl radicals, another common constituent of molecular clouds, readily combine to form larger and more complex organic compounds.

"We knew we were onto something good," Bouwman said.

The team then drew on computer models to explore the role of ortho-benzyne in a stellar nursery spread out over several light years deep in space. The results were promising: The models generated clouds of gas containing roughly the same mix of organic molecules that astronomers had observed in TMC-1 using telescopes.

Ortho-benzyne, in other words, seems to be a prime candidate for driving the gas-phase organic chemistry that occurs within these stellar nurseries, Bouwman said.

He added that scientists still have a lot of work to do to fully understand all the reactions happening in TMC-1. He wants to examine, for example, how organic molecules in space also pick up nitrogen atoms -- key components of the DNA and amino acids of living organisms on Earth.

"Our findings may just change the view on what ingredients we have in the first place to form new stars and new planets," Bouwman said.

Read more at Science Daily

Prehistoric human migration in Southeast Asia driven by sea-level rise

An interdisciplinary team of scientists at Nanyang Technological University, Singapore (NTU, Singapore) has found that rapid sea-level rise drove early settlers in Southeast Asia to migrate during the prehistoric period, increasing the genetic diversity of the region today.

The Malay Peninsula and the islands of Sumatra, Borneo, and Java were originally part of a large landmass of rainforests and coastal mangroves in the South Asia continental shelf known as 'The Sundaland' some 26,000 years ago.

But during the last major period of global warming in Earth's history, from the Last Glacial Maximum period (approximately 26,000 -- 20,000 years ago) to the mid-50 Holocene (approximately 6,000 years ago), sea level rose 130 metres. The rise in sea level flooded and submerged half of The Sundaland, breaking land bridges and splitting the large landmass into smaller islands of the region today.

To understand the impact on humans living in The Sundaland during one of the most dramatic sea-level rises in the Earth's history, the team of NTU Singapore scientists reconstructed the history of the landmass using two different approaches: paleogeography -- the study of historical physical landscapes, and population genetics.

Lead investigator, Assistant ProfessorKim Hie Lim from NTU's Asian School of the Environment (ASE), and the Singapore Centre for Environmental Life Sciences Engineering (SCELSE) at NTU said, "Environmental changes have profound impacts on human history, driving population migration, growth, and distribution. However, less discussed is how environmental changes can shape the genetics of populations. Our work is the first reported instance to provide proof that sea-level rise changed the genetic makeup of human populations in Southeast Asia -- a legacy that continues to impact current populations."

Using data for Southeast and South Asia's sea-level history, including ancient Singapore records established by the NTU's Earth Observatory of Singapore (EOS) and ASE, the research team constructed paleogeographic maps dating from 26,000 years ago to the present.

The NTU team also used whole-genome sequence data from 59 ethnic groups, including that belonging to populations native to Southeast and South Asia from 50,000 years ago. By analysing the high-quality genome data, the team was able to infer the genetic ancestry and demographic history of the groups, including their population size and distribution.

While researchers elsewhere have studied population history based on genetics, most of them used mitochondrial DNA (genes inherited from the mother), which does not tell the full picture of individual ancestry.

By using whole-genome sequence data -- precise information of an individual's entire genetic makeup inherited from both the mother and the father -- the NTU study offers an unbiased demographic history of the indigenous populations inhabiting The Sundaland.

The whole-genome sequence data was generated by the non-profit organisation GenomeAsia 100K. Launched in 2016 and hosted by NTU, the initiative aims to better understand the genome diversity of Asian ethnicities by sequencing 100,000 genomes of people living in Asia.

Contributing author, Professor Stephan Schuster, President's Chair in Genomics at NTU's School of Biological Sciences, Research Director of SCELSE, and Scientific Chair of GenomeAsia 100K, said, "GenomeAsia 100K systematically generates maps of Asian human genetic diversity, including indigenous ethnicities who have occupied the region for a long time. Integrating those maps with paleoclimatic data allows us now to understand exactly how past climatic events have resulted in ancient human migrations, as well as their impact on today's population structure."

The research is aligned with the NTU 2025 strategy, where the University adopts more collaborative, global and interdisciplinary means of research to address Singapore's national research priorities, such as health & society.

Piecing together the story of human migration in ancient Sundaland

Combining findings from the two approaches, the scientists inferred the changes in population density from the high quality historical paleogeographic maps generated.

The map paints a picture of prehistoric human migration in The Sundaland, showing that the earliest documented instance of forced human migration was driven by sea level rise.

The scientists found that two periods of rapid sea level rise (rates of sea level rise at46 mm/year and 22 mm/year)promoted the separation of populations into smaller groups across The Sundaland, as the large landmass became split into smaller islands, forcing people to disperse.

Even as the landmass decreased after the rapid sea level rises, temperature increased from the Last Glacial Maximum, creating a favourable living environment to support human population growth. This caused population density to surge by at least eight times from the Last Glacial Maximum, especially in the Island Southeast Asian region, including Malay Peninsula, Sumatra, and Borneo.

As a result, overpopulation drove people to migrate in search of new places to settle and the people in The Sundaland later migrated back northwards, towards Mainland Southeast Asia and South Asia.

This finding is supported by evidence of migration by the ancestors of the Malaysian indigenous group (Malaysia Negrito, or commonly referred to as 'Orang Asli') into South Asian tribal groups (Austroasiatic speakers). Genetic analysis confirmed common genetic ancestry between the Malaysian and South Asian indigenous groups.

The entire process of migration therefore shaped the diverse ethnicities across Southeast and South Asian regions, as early settlers of The Sundaland interbred across different indigenous groups.

Co-author of the study, Dr Li Tanghua, Senior Research Fellow at NTU's EOS said, "Based on our findings, the Orang Asli Malaysian indigenous group can be considered the first 'casualties' of sea-level rise, or what are known as 'climate refugees' today. The population had no choice but to move from their original territory due to environmental pressures. This forced migration caused an indelible change to the genetic footprint of South Asians, contributing to one of the most ethnically diverse regions in the world."

Findings useful to understand impact of sea level rise on human ancestry

The study, published in the peer-reviewed journal Communications Biology in February, is the first to trace the impact of prehistoric sea level rise to human ancestry in Southeast Asia.

Co-author of the study, Professor Benjamin Horton, Director of NTU's EOS, said, "The study of past sea levels is essential to predicting how increasing amounts of atmospheric carbon dioxide will alter Earth's climate and raise future sea levels. These projections inform how societies can mitigate and adapt to climate change impacts."

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Study reveals new clues about how 'Earth's thermostat' controls climate

Rocks, rain and carbon dioxide help control Earth's climate over thousands of years -- like a thermostat -- through a process called weathering. A new study led by Penn State scientists may improve our understanding of how this thermostat responds as temperatures change.

"Life has been on this planet for billions of years, so we know Earth's temperature has remained consistent enough for there to be liquid water and to support life," said Susan Brantley, Evan Pugh University Professor and Barnes Professor of Geosciences at Penn State. "The idea is that silicate rock weathering is this thermostat, but no one has ever really agreed on its temperature sensitivity."

Because many factors go into weathering, it has been challenging to use results of laboratory experiments alone to create global estimates of how weathering responds to temperature changes, the scientists said.

The team combined laboratory measurements and soil analysis from 45 soil sites around the world and many watersheds to better understand weathering of the major rock types on Earth and used those findings to create a global estimate for how weathering responds to temperature.

"When you do experiments in the laboratory versus taking samples from soil or a river, you get different values," Brantley said. "So what we tried to do in this research is look across those different spatial scales and figure out how we can make sense of all this data geochemists around the world been accumulating about weathering on the planet. And this study is a model for how we can do that."

Weathering represents part of a balancing act of carbon dioxide in Earth's atmosphere. Volcanoes have emitted large amounts of carbon dioxide through Earth's history, but instead of turning the planet into a hot house, the greenhouse gas is slowly removed via weathering.

Rain takes the carbon dioxide from the atmosphere and creates a weak acid that falls to Earth and wears away silicate rocks the surface. The byproducts are carried by streams and rivers to the ocean where the carbon is eventually locked away in sedimentary rocks, the scientists said.

"It has long been hypothesized that the balance between carbon dioxide entering the atmosphere from volcanoes and being pulled out by weathering over millions of years holds the temperature of the planet relatively constant," Brantley said. "The key is when there is more carbon dioxide in the atmosphere and the planet gets hotter, weathering goes faster and pulls more carbon dioxide out. And when the planet is cooler, weathering slows down."

But much remains unknown about how sensitive weathering is to changing temperatures, partly because of the long spatial and time scales involved.

"In a soil profile, you are seeing a picture of soil where the camera shutter was open for sometimes a million years -- there are integrated processes happening for a million years and you're trying to compare that with a two-year flask experiment," Brantley said.

Brantley said the field of critical zone science -- which examines landscapes from the tallest vegetation to the deepest groundwater -- has helped scientists better understand the complex interactions that influence weathering.

For example, rocks must fracture for water to get in cracks and start breaking down the materials. For that to happen, the rock must have large, exposed surface areas, and that is less likely to happen in regions where soil is deeper.

"It's only when you start crossing spatial and time scales that you start seeing what's really important," Brantley said. "Surface area is really important. You can measure all the rate constants you want for that solution in the lab, but until you can tell me how does surface area form out there in the natural system, you are never going to be able to predict the real system."

The scientists reported in the journal Science that temperature sensitivity measurements in the laboratory were lower than estimates from soils and rivers in their study. Using observations from the lab and field sites, they upscaled their findings to estimate the global temperature dependance of weathering.

Their model may be helpful for understanding how weathering will respond to future climate change, and in evaluating human-made attempts to increase weathering to draw more carbon dioxide from the atmosphere -- like carbon sequestration.

"One idea has been to enhance weathering by digging up a lot of rock, grinding it, transporting it and putting it out in the fields to let weathering happen," Brantley said. "And that will work -- it's already working. The problem is, it's a very slow process."

Though warming may speed up weathering, pulling all the carbon dioxide out of the atmosphere that humans have added could take thousands or hundreds of thousands of years, the scientists said.

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Why microbes in the deep ocean live without sunlight

A world first study reverses the idea that the bulk of life in the ocean is fuelled by photosynthesis via sunshine, revealing that many ocean microbes in fact get their energy from hydrogen and carbon monoxide.

It has always been a mystery as to how microbes growing in deepest parts of the sea survive, with no sunlight. A new study, from researchers at the Monash University published in the journal Nature Microbiology, shows that a distinct process called chemosynthesis -- growth using inorganic compounds -- fuels microbes in these darkest depths.

The five-year study, led by Dr Rachael Lappan and Professor Chris Greening from the Biomedicine Discovery Institute, reveals that two common gases -- hydrogen and carbon monoxide -- serve as the fuel for trillions of microbes in the ocean from the tropics to the poles.

According to Professor Greening, until now most scientists have believed that ocean microbial life is primarily driven by photosynthesis (growth by using light energy). "But what about those regions so deep that light can't penetrate or so nutrient-poor that algae can't thrive? We showed in this study that instead chemosynthesis is dominant in these regions," he said.

"Hydrogen and carbon monoxide in fact "fed" microbes in all regions we've looked at: from urban bays to around tropical islands to hundreds of metres below the surface. Some can even be found beneath Antarctica's ice shelves."

The study involved combining chemical measurements during oceanic voyages with laboratory-based characterisation of microbial cultures. The research team also extensively used metagenomic sequencing, "which tells us the genetic blueprints of all of the microbes present in a given region of the ocean," Dr Lappan said. "We found the genes that enable hydrogen consumption across eight distantly related types of microbes, known as phyla, and this survival strategy becomes more common the deeper they live."

For this project, the researchers were inspired by their previous work on soil bacteria. Professor Greening and colleagues have previously showed most soil bacteria can live by consuming hydrogen and carbon monoxide from the atmosphere.

"The surface layers of the world's oceans generally contain high levels of dissolved hydrogen and carbon monoxide gases due to various geological and biological processes. So it made sense that oceanic bacteria used the same gases as their terrestrial cousins," Dr Lappan said.

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Ultra-processed foods may be linked to increased risk of cancer

Higher consumption of ultra-processed foods may be linked to an increased risk of developing and dying from cancer, an Imperial College London-led observational study suggests.

Researchers from Imperial’s School of Public Health have produced the most comprehensive assessment to date of the association between ultra-processed foods and the risk of developing cancers. Ultra-processed foods are food items which have been heavily processed during their production, such as fizzy drinks, mass-produced packaged breads, many ready meals and most breakfast cereals.

Ultra-processed foods are often relatively cheap, convenient, and heavily marketed, often as healthy options. But these foods are also generally higher in salt, fat, sugar, and contain artificial additives. It is now well documented that they are linked with a range of poor health outcomes including obesity, type 2 diabetes and cardiovascular disease.

The first UK study of its kind used UK Biobank records to collect information on the diets of 200,000 middle-aged adult participants. Researchers monitored participants’ health over a 10-year period, looking at the risk of developing any cancer overall as well as the specific risk of developing 34 types of cancer. They also looked at the risk of people dying from cancer.

The study found that higher consumption of ultra-processed foods was associated with a greater risk of developing cancer overall, and specifically with ovarian and brain cancers. It was also associated with an increased risk of dying from cancer, most notably with ovarian and breast cancers.

For every 10 per cent increase in ultra-processed food in a person’s diet, there was an increased incidence of 2 per cent for cancer overall, and a 19 per cent increase for ovarian cancer specifically.

Each 10 per cent increase in ultra-processed food consumption was also associated with increased mortality for cancer overall by 6 per cent, alongside a 16 per cent increase for breast cancer and a 30 per cent increase for ovarian cancer.

These links remained after adjusting for a range of socio-economic, behavioural and dietary factors, such as smoking status, physical activity and body mass index (BMI).

The Imperial team carried out the study, which is published in eClinicalMedicine, in collaboration with researchers from the International Agency for Research on Cancer (IARC), University of São Paulo, and NOVA University Lisbon.

Previous research from the team reported the levels of consumption of ultra-processed foods in the UK, which are the highest in Europe for both adults and children. The team also found that higher consumption of ultra-processed foods was associated with a greater risk of developing obesity and type 2 diabetes in UK adults, and a greater weight gain in UK children extending from childhood to young adulthood.

Dr Eszter Vamos, lead senior author for the study, from Imperial College London’s School of Public Health, said: “This study adds to the growing evidence that ultra-processed foods are likely to negatively impact our health including our risk for cancer. Given the high levels of consumption in UK adults and children, this has important implications for future health outcomes.

“Although our study cannot prove causation, other available evidence shows that reducing ultra-processed foods in our diet could provide important health benefits. Further research is needed to confirm these findings and understand the best public health strategies to reduce the widespread presence and harms of ultra-processed foods in our diet.”

Dr Kiara Chang, first author for the study, from Imperial College London’s School of Public Health, said: “The average person in the UK consumes more than half of their daily energy intake from ultra-processed foods. This is exceptionally high and concerning as ultra-processed foods are produced with industrially derived ingredients and often use food additives to adjust colour, flavour, consistency, texture, or extend shelf life.

“Our bodies may not react the same way to these ultra-processed ingredients and additives as they do to fresh and nutritious minimally processed foods. However, ultra-processed foods are everywhere and highly marketed with cheap price and attractive packaging to promote consumption. This shows our food environment needs urgent reform to protect the population from ultra-processed foods.”

The World Health Organisation and the United Nations’ Food and Agriculture Organisation has previously recommended restricting ultra-processed foods as part of a healthy sustainable diet.

There are ongoing efforts to reduce ultra-processed food consumption around the world, with countries such as Brazil, France and Canada updating their national dietary guidelines with recommendations to limit such foods. Brazil has also banned the marketing of ultra-processed foods in schools. There are currently no similar measures to tackle ultra-processed foods in the UK.

Dr Chang added: “We need clear front of pack warning labels for ultra-processed foods to aid consumer choices, and our sugar tax should be extended to cover ultra-processed fizzy drinks, fruit-based and milk-based drinks, as well as other ultra-processed products.

“Lower income households are particularly vulnerable to these cheap and unhealthy ultra-processed foods. Minimally processed and freshly prepared meals should be subsidised to ensure everyone has access to healthy, nutritious and affordable options.”

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Monitoring an 'anti-greenhouse' gas: Dimethyl sulfide in Arctic air

Data stored in ice cores dating back 55 years bring new insight into atmospheric levels of a molecule that can significantly affect weather and climate.

Dimethyl sulfide (C2H6S) is a small molecule released by phytoplankton in the ocean, which can play a big role in regulating the Earth's climate. It encourages cloud formation above the sea, and is often called an 'anti-greenhouse gas', since clouds block radiation from the sun and lower sea surface temperatures. At least some blocked heat will be retained in the atmosphere, however, so the effects can be complex. Researchers at Hokkaido University have charted evidence for increasing dimethyl sulfide emissions linked to the retreat of sea ice from Greenland as the planet warms. They report their findings in the journal Communications Earth & Environment.

Modelling studies have long suggested that the decline in Arctic sea ice could lead to increased dimethyl sulfide emission, but direct evidence for this has been lacking. Assistant Professor Sumito Matoba and colleagues have inferred dimethyl sulfide levels over 55 years by quantifying the related compound, methane sulfonic acid (MSA), in ice core samples from the south-east Greenland ice sheet. MSA is directly produced from dimethyl sulfide, serving as a stable record of dimethyl sulfide levels. This process is part of a variety of chemical interactions among aerosols in the atmosphere.

The team, including researchers from Nagoya University and Japan's Aerospace Exploration Agency, reconstructed the annual and seasonal MSA flux from 1960 to 2014, at a monthly resolution. The annual MSA levels decreased from 1960 to 2001, but then markedly increased after 2002.

"We found that July to September MSA fluxes were three to six times higher between 2002 and 2014 than between 1972 and 2001," says Matoba. "We attribute this to the earlier retreat of sea ice in recent years."

Supporting evidence comes from satellite data that has monitored the levels of the crucial sunlight-absorbing green pigment chlorophyll-a in the surrounding seas. The chlorophyll-a serves as an indicator of phytoplankton abundance, which in turn should correlate well with the amount of dimethyl sulfide released by the phytoplankton.

Arctic temperatures are rising twice as fast as the global average, and the summer seasonal sea ice extent has declined sharply in recent decades. This increases the amount of light striking the ocean and promotes the growth of phytoplankton.

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Reducing their natural signals: How sneaky germs hide from ants

Not only humans are social, ants are too. Group members are taking care of sick ones by providing collective hygiene measures. This presents germs with a task. They must circumvent the immunity of an individual ant and avoid the group's healthcare. A new study now published in Nature Ecology & Evolution reveals that germs develop a sneaky way to escape the ant colony's defense systems by reducing their detection cues.

Pathogens are disease-causing organisms. By natural selection, they develop evading mechanisms to outsmart the host's immune system and to get the upper hand. One way to support the immune system and fight back is medical intervention. However, this can lead to unwanted adaptions of pathogens as seen in antibiotic-resistant bacteria. Another strategy is social intervention. Some social groups like ants are trying to fight infection with "social immunity," the collective hygiene and health care measures to avoid spreading throughout the community. If and how pathogens can respond to this kind of group behavior, is still unknown.

The latest study by Professor Sylvia Cremer and her research team at the Institute of Science and Technology Austria (ISTA) shows the extraordinary effects of these kinds of host-parasite interactions. Together, with chemical ecologists at the University of Würzburg in Germany, the scientists took a close look at social ants, to see how pathogenic fungi respond to their hosts' social care intervention during infection. The results reveal that fungi reduce their chemical detection signals to outplay social immunity. The study is published today in Nature Ecology & Evolution.

More spores but less grooming

"Fungi infect the ants from the body surface and grow inside, but nestmates groom off many of the spores before they can even cause internal infection," explains Barbara Milutinović, one of the lead authors, former postdoc in the Cremer Group and now Marie Curie Sklodowska Fellow at Ruđer Bošković Institute in Croatia. The scientists set up an experiment where Argentine ants (Linepithemahumile) were infected with pathogenic Metarhizium fungi either in the absence or presence of caregiving colony members. "We found that the fungi fundamentally changed in response to the ant workers' caregiving," Milutinović continues. Over ten infection cycles, fungi which experienced grooming nestmate ants boosted their spore production compared to fungi accompanied by only individual ants. "Producing more spores will help the fungus counteract the spore-removal by helping nestmates. Yet, we were surprised to see that the ants showed less grooming against the spores," Sylvia Cremer adds. "This suggests, that the spores have become more difficult to detect by the ants."

Fungi lose their typical chemical profile

To check why ant workers had difficulties sensing fungi and to analyze possible fungal detection cues, the scientists teamed up with a chemical ecologist from the University of Würzburg. Local Professor Thomas Schmitt explains: "The fungi, that adapted to social hosts were perceived less strongly, due to a strong reduction of a fungi-specific compound called ergosterol." Ergosterol is an essential membrane compound, that all fungi have. By exposing the ants to pure fungal ergosterol or the slightly different non-fungal vertebrate equivalent, the researchers showed, that only the fungal compound induced intense grooming. Milutinović summarizes: "This demonstrates that fungal pathogens react to the presence of caregiving ants by reducing their characteristic fungal signals. They are no longer recognized as a disease threat and can escape the social immunity of the colony."

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