DENVER — A hidden landscape riddled with landslides is coming into focus in Yellowstone National Park, thanks to a laser-equipped airplane.

Scientists of yore crisscrossed Yellowstone on foot and studied aerial photographs to better understand America’s first national park. But today researchers have a massive new digital dataset at their fingertips that’s shedding new light on this nearly 1-million-hectare natural wonderland.

These observations of Yellowstone have allowed a pair of researchers to pinpoint over 1,000 landslides within and near the park, hundreds of which had not been mapped before, the duo reported October 9 at the Geological Society of America Connects 2022 meeting. Most of these landslides likely occurred thousands of years ago, but some are still moving.
Mapping Yellowstone’s landslides is important because they can cripple infrastructure like roadways and bridges. The millions of visitors that explore the park each year access Yellowstone through just a handful of entrance roads, one of which recently closed for months following intense flooding.

In 2020, a small aircraft flew a few hundred meters above the otherworldly landscape of Yellowstone. But it wasn’t ferrying tourists eager for up close views of the park’s famous wolves or hydrothermal vents (SN: 7/21/20, SN: 1/11/21). Instead, the plane carried a downward-pointing laser that fired pulses of infrared light at the ground. By measuring the timing of pulses that hit the ground and reflected back toward the aircraft, researchers reconstructed the precise topography of the landscape.

Such “light detection and ranging,” or lidar, data reveal details that often remain hidden to the eye. “We’re able to see the surface of the ground as if there’s no vegetation,” says Kyra Bornong, a geoscientist at Idaho State University in Pocatello. Similar lidar observations have been used to pinpoint pre-Columbian settlements deep within the Amazon jungle (SN: 5/25/22).

The Yellowstone lidar data were collected as part of the 3D Elevation Program, an ongoing project spearheaded by the United States Geological Survey to map the entirety of the United States using lidar.
Bornong and geomorphologist Ben Crosby analyzed the Yellowstone data — which resolve details as small as about one meter — to home in on landslides. The team searched for places where the landscape changed from looking relatively smooth to looking jumbled, evidence that soil and rocks had once been on the move. “It’s a pattern-recognition game,” says Crosby, also of Idaho State University. “You’re looking for this contrast between the lumpy stuff and the smooth stuff.”

The researchers spotted more than 1,000 landslides across Yellowstone, most of which were clustered near the periphery of the park. That makes sense given the geography of Yellowstone’s interior, says Lyman Persico, a geomorphologist at Whitman College in Walla Walla, Wash., who was not involved in the research. The park sits atop a supervolcano, whose previous eruptions blanketed much of the park in lava (SN: 1/2/18). “You’re sitting in the middle of the Yellowstone caldera, where everything is flat,” says Persico.

But steep terrain also abounds in the national park, and there’s infrastructure in many of those landslide-prone areas. In several places, the team found that roads had been built over landslide debris. One example is Highway 191, which skirts the western edge of Yellowstone.

An aerial image of U.S. Highway 191 near Yellowstone shows barely perceptible signs of a long-ago landslide. But laser mapping reveals the structure and extent of the landslide in much greater detail (use the slider to compare images). It’s one of more than 1,000 landslides uncovered by new maps.
It’s worth keeping an eye on this highway since it funnels significant amounts of traffic through regions apt to experience landslides, Bornong says. “It’s one of the busiest roads in Montana.”

There’s plenty more to learn from this novel look at Yellowstone, Crosby says. Lidar data can shed light on geologic processes like volcanic and tectonic activity, both of which Yellowstone has in spades. “It’s a transformative tool,” he says.

It was the rift watched ‘round the world.

In July 2017, after weeks of anticipation, a massive iceberg about the size of Delaware split from the Antarctic Peninsula (SN: 7/12/17). Satellite images show that the orphaned iceberg, known as A68, ultimately disintegrated in the Southern Ocean. Now, researchers say they have pieced together the powerful forces that led to that final breakup.

Polar scientist Alex Huth of Princeton University and colleagues combined observations of the iceberg’s drift with simulations of ocean currents and wind stress. Iceberg A68a, the largest remaining chunk of the original berg, was caught in a tug-of-war of ocean currents, and the strain of those opposing forces probably pulled the iceberg apart, the team reports October 19 in Science Advances.
After A68’s separation from the Larsen C ice shelf, researchers had questions — such as what creatures live on the seafloor in the ice’s dark shadow (SN: 2/8/19). As for the iceberg itself, it took a while to get moving, lingering in the neighborhood for about a year (SN: 7/23/18). By December 2020, satellite images show, the berg had clearly seen some action and was just two-thirds of its original size.
The new simulations suggest how A68a probably met its fate. On December 20, 2020, the long, slender “finger” at one end of the iceberg drifted into a strong, fast-moving current. The rest of the ice remained outside the current. The tension rifted the berg, and the finger sheared off and broke apart within a few days.

Shear stress is a previously unknown mechanism for large iceberg breakup, and isn’t represented in climate simulations, the team says. In the Southern Ocean, the melting of massive bergs can be a large source of cold freshwater to the ocean surface. That, in turn, can have a big impact on ocean circulation and the global climate.

U.S. millennials are rejecting suburbia and moving back to the city. That was a prevailing idea in 2019, when I started as the social sciences reporter at Science News. But when I began digging into a possible story on the phenomenon, I encountered an incoherent mess. Some research showed that suburbs were growing, others that suburbs were shrinking and yet others showed growth in both suburbs and cities.

Unable to make sense of that maze of findings, I shelved the story idea. Then, several months later, I stumbled across a Harvard University white paper explaining that disagreement in the field stems from competing definitions of what distinguishes a city from a suburb. Some researchers define the suburbs as areas falling outside census-designated cities. Others look only for markers of suburbanism, such as a wealth of single-family houses and car-based commutes, the researchers wrote.
I have encountered this type of fuzziness around definitions of all sorts of terms and concepts in the years I’ve covered the social sciences. Sometimes researchers simply assume that their definition of a key concept is the definition. Or they nod briefly at other definitions, and then go forth with whichever one they choose, without much explanation why. Other times, researchers in one subfield choose one definition, and researchers in another subfield choose a different one — each without ever knowing of the other’s existence. It’s enough to drive any reporter to tear their hair out.

“If you look … you will find this morass of definitions and measurements” in the social sciences, says quantitative psychologist Jessica Flake of McGill University in Montreal. My experience was a common one, she assured me.

Definitional morasses exist in other scientific fields too. Biologists frequently disagree about how best to define the word “species” (SN: 11/1/17). Virologists squabble over what counts as “alive” when it comes to viruses (SN: 11/1/21). And not all astronomers are happy with the decision to define the word “planet” in a way that left Pluto out in the cold as a mere dwarf planet (SN: 8/24/21).

But the social sciences have some special challenges, Flake says. The field is a youngster compared with a discipline like astronomy, so has had less time to sort out its definitions. And social science concepts are often inherently subjective. Describing abstract ideas like motivation or feelings can be squishier than describing, say, a meteorite.

It’s tempting to assume, as I did until I began researching this column, that a single, imperfect definition for individual concepts is preferable to this definitional cacophony. And some researchers encourage this approach. “While no suburban definition will be perfect, standardization would increase understanding of how suburban studies relate to each other,” the Harvard researchers wrote in that suburbia paper.

But a recent study taking aim at how we define the middle class showed me how alternative definitions can lead to a shift in perspective.

While most researchers use income as a proxy for class, these researchers used people’s buying patterns. That revealed that a fraction of people who appear middle class by income struggle to pay for basic necessities, such as housing, child care and groceries, the team reported in July in Social Indicators Research. That is, they live as if they are working class.

What’s more, that vulnerable group skews Black and Hispanic, a disparity that arises, in part, because these families of color often lack the generational wealth of white families, says Melissa Haller, a geographer at Binghamton University in New York. So when calamity strikes, families without that financial cushion can struggle to recover. Yet a government or nonprofit organization looking to direct aid toward the neediest families, and relying solely on income-based metrics, would overlook this vulnerable group.

“Depending on what definition you start with, you will see different facts,” says Anna Alexandrova, a philosopher of science at the University of Cambridge. A standardized definition of middle class, for example, could obscure some of those key facts.

In the social sciences, what’s needed instead of conceptual unity, Alexandrova says, is conceptual clarity.

Though social scientists disagree about how to go about solving this problem of clarity, Flake says that failure to tackle the issue jeopardizes the field as much as other crises rocking the discipline (SN: 8/27/18). That’s because how a topic is defined determines the scales, surveys and other instruments used to study that concept. And that in turn shapes how researchers crunch numbers and arrive at conclusions.

Defining one’s key terms and then selecting the right tool is somewhat straightforward when relying on large, external datasets. For instance, instead of using national income databases, as is common in the study of the middle class, Haller and her team turned to the federal government’s Consumer Expenditure Surveys to understand people’s daily and emergency purchases.

But often social scientists, particularly psychologists, develop their own scales and surveys to quantify subjective concepts, such as self-esteem, mood or well-being. Definitions of those terms — and the instruments used to study them — can take on a life of their own, Flake says.

She and her team recently showed how this process plays out in the May-June American Psychologist. They combed through the 100 original studies and 100 replications included in a massive reproducibility project in psychology. The researchers zoomed in on 97 multi-item scales — measuring concepts such as gratitude, motivation and self-esteem — used in the original studies, and found that 54 of those scales had no citations to show where the scales originated. That suggests that the original authors defined their idea, and the tool used to measure that idea, on the fly, Flake says. Research teams then attempted to replicate 29 of those studies without digging into the scales’ sources, calling into question the meaning of their results.

For Flake, the way to achieve conceptual clarity is straightforward, if unlikely. Researchers must hit the brakes on generating new ideas, or replicating old ideas, and instead interrogate the morass of old ones.

She points to one promising, if labor-intensive, effort: the Psychological Science Accelerator, a collaboration of over 1,300 researchers in 84 countries. The project aims to identify big ideas in psychology, such as face perception and gender prejudice, and accumulate all the instruments and resulting data used to make sense of those ideas in order to discard, refine or combine existing definitions and tools.

“Instead of running replications, why don’t we use [this] massive team of researchers who represent a lot of perspectives around the world and review concepts first,” Flake says. “We need to stop replicating garbage.”

I couldn’t agree more.

Wind turbines could offer a double whammy in the fight against climate change.

Besides harnessing wind to generate clean energy, turbines may help to funnel carbon dioxide to systems that pull the greenhouse gas out of the air (SN: 8/10/21). Researchers say their simulations show that wind turbines can drag dirty air from above a city or a smokestack into the turbines’ wakes. That boosts the amount of CO2 that makes it to machines that can remove it from the atmosphere. The researchers plan to describe their simulations and a wind tunnel test of a scaled-down system at a meeting of the American Physical Society’s Division of Fluid Dynamics in Indianapolis on November 21.
Addressing climate change will require dramatic reductions in the amount of carbon dioxide that humans put into the air — but that alone won’t be enough (SN: 3/10/22). One part of the solution could be direct air capture systems that remove some CO2 from the atmosphere (SN: 9/9/22).

But the large amounts of CO2 produced by factories, power plants and cities are often concentrated at heights that put it out of reach of machinery on the ground that can remove it. “We’re looking into the fluid dynamics benefits of utilizing the wake of the wind turbine to redirect higher concentrations” down to carbon capture systems, says mechanical engineer Clarice Nelson of Purdue University in West Lafayette, Ind.

As large, power-generating wind turbines rotate, they cause turbulence that pulls air down into the wakes behind them, says mechanical engineer Luciano Castillo, also of Purdue. It’s an effect that can concentrate carbon dioxide enough to make capture feasible, particularly near large cities like Chicago.

“The beauty is that [around Chicago], you have one of the best wind resources in the region, so you can use the wind turbine to take some of the dirty air in the city and capture it,” Castillo says. Wind turbines don’t require the cooling that nuclear and fossil fuel plants need. “So not only are you producing clean energy,” he says, “you are not using water.”

Running the capture systems from energy produced by the wind turbines can also address the financial burden that often goes along with removing CO2 from the air. “Even with tax credits and potentially selling the CO2, there’s a huge gap between the value that you can get from capturing it and the actual cost” that comes with powering capture with energy that comes from other sources, Nelson says. “Our method would be a no-cost added benefit” to wind turbine farms.

There are probably lots of factors that will impact CO2 transport by real-world turbines, including the interactions the turbine wakes have with water, plants and the ground, says Nicholas Hamilton, a mechanical engineer at the National Renewable Energy Laboratory in Golden, Colo., who was not involved with the new studies. “I’m interested to see how this group scaled their experiment for wind tunnel investigation.”

You might feel a spark when you talk to your crush, but living things don’t require romance to make electricity. A study published October 24 in iScience suggests that the electricity naturally produced by swarming insects like honeybees and locusts is an unappreciated contributor to the overall electric charge of the atmosphere.

“Particles in the atmosphere easily charge up,” says Joseph Dwyer, a physicist at the University of New Hampshire in Durham who was not involved with the study. “Insects are little particles moving around the atmosphere.” Despite this, the potential that insect-induced static electricity plays a role in the atmosphere’s electric field, which influences how water droplets form, dust particles move and lightning strikes brew, hasn’t been considered before, he says.
Scientists have known about the minuscule electric charge carried by living things, such as insects, for a long time. However, the idea that an electric bug-aloo could alter the charge in the air on a large scale came to researchers through sheer chance.

“We were actually interested in understanding how atmospheric electricity influences biology,” says Ellard Hunting, a biologist at the University of Bristol in England. But when a swarm of honeybees passed over a sensor meant to pick up background atmospheric electricity at the team’s field station, the scientists began to suspect that the influence could flow the other way too.

Hunting and colleagues, including biologists and physicists, measured the change in the strength of electric charge when other honeybee swarms passed over the sensor, revealing an average voltage increase of 100 volts per meter. The denser the insect swarm, the greater the charge produced.

This inspired the team to think about even larger insect swarms, like the biblical hordes of locusts that plagued Egypt in antiquity (and, in 2021, Las Vegas (SN: 3/30/21)). Flying objects, from animals to airplanes, build up static electricity as they move through the air. The team measured the charges of individual desert locusts (Schistocerca gregaria) as they flew in a wind tunnel powered by a computer fan. Taking data on locust density from other studies, the team then used a computer simulation based on the honeybee swarm data to scale up these single locust measurements into electric charge estimates for an entire locust swarm. Clouds of locusts could produce electricity on a per-meter basis on par with that in storm clouds, the scientists report.

Hunting says the results highlight the need to explore the unknown lives of airborne animals, which can sometimes reach much greater heights than honeybees or locusts. Spiders, for example, can soar kilometers above Earth when “ballooning” on silk threads to reach new habitats (SN: 7/5/18). “There’s a lot of biology in the sky,” he says, from insects and birds to microorganisms. “Everything adds up.”

Though some insect swarms can be immense, Dwyer says that electrically charged flying animals are unlikely to ever reach the density required to produce lightning like storm clouds do. But their presence could interfere with our efforts to watch for looming strikes that could hurt people or damage property.

“If you have something messing up our electric field measurements, that could cause a false alarm,” he says, “or it could make you miss something that’s actually important.” While the full effect that insects and other animals have on atmospheric electricity remains to be deduced, Dwyer says these results are “an interesting first look” into the phenomenon.

Hunting says this initial step into an exciting new area of research shows that working with scientists from different fields can spark shocking findings. “Being really interdisciplinary,” he says, “allows for these kinds of serendipitous moments.”

Aye-ayes are true champions of nose picking.

A new video offers the first evidence that these nocturnal lemurs of Madagascar stick their fingers up their noses and lick off the mucus. They don’t use just any finger for the job, either. The primates go spelunking for snot with the ultralong, witchy middle finger they typically use to find and fish grubs out of tree bark.

A reconstruction of the inside of an aye-aye’s head based on CT scans shows that this spindly digit probably pokes all the way through the animal’s nasal passages to reach its throat, researchers report online October 26 in the Journal of Zoology.
“This is a brilliant example of how science can serve human curiosity,” says Michael Haslam, a primate archaeologist based in London who was not involved in the new work. “My first take was that it’s a cool — and a bit creepy — video, but [the researchers] have gone beyond that initial reaction of ‘What on Earth?’ to actually explore what’s happening inside the animal.”

The new footage stars Kali, a female aye-aye (Daubentonia madagascariensis) at the Duke Lemur Center in Durham, N.C. “The aye-aye stopped eating and started to pick its nose, and I was really surprised,” says evolutionary biologist Anne-Claire Fabre, who filmed the video. “I was wondering where the finger was going.” An aye-aye is about as big as a house cat, but its clawed middle finger is some 8 centimeters long. And Kali was plunging almost the entire digit up her snout to sample her own snot with dainty licks.

“There is one moment where the camera is [shaking], and I was giggling,” says Fabre, of the Natural History Museum of Bern in Switzerland. Afterward, she asked her colleagues if they had ever seen an aye-aye picking its nose. “The ones that were working a lot with aye-ayes would tell me, ‘Oh, yeah, it’s happening really often,’” says Fabre, who later witnessed the behavior in several other aye-ayes.
This got Fabre and her colleagues curious about how many other primate species have been caught with their fingers in their nostrils. The researchers scoured the literature for past studies and the internet for other videos documenting the behavior.

Unfortunately, “most of the literature that we were finding were jokes,” Fabre says. “I was really surprised, because there is a lot of literature on other types of pretty gross behaviors, such as coprophagy,” or poo eating, among animals (SN: 7/19/21). But between all the bogus articles, the team did find some real reports of primate nose picking, including research done by Jane Goodall in the 1970s.

Aye-ayes are now the 12th known species of primate, including humans, to pick their noses and snack on the snot, the researchers found. Others include gorillas, chimpanzees, bonobos, orangutans and macaques. Nose pickers tend to be primates that have especially good dexterity and use tools.

“The team [has] given us the first map of nose picking across our primate family tree, which immediately raises questions about just how much of this behavior is happening out there, unseen or unreported,” Haslam says. He remembers once seeing a capuchin monkey using a twig or stem to pick its nose (SN: 9/6/15).

“I’m surprised that there aren’t more reports on nose picking, especially from zoos where animals are watched every day,” Haslam adds. “Perhaps our own social stigma around it means that scientists are less likely to want to report nose-picking animals, or it may even be seen as too common to be interesting.”
The fact that so many primate species have been spotted picking their noses and eating the boogers makes Fabre’s team and Haslam wonder whether this seemingly nasty habit has some unknown advantage. Perhaps eating germ-laden boogers boosts the immune system.

For now, untangling the evolutionary origins and potential perks of nose picking will require a more complete census of what species — primate or otherwise — mine and munch on their own mucus.

A fierce group of predatory dinosaurs may have done much of their hunting in the water.

An analysis of the bone density of several sharp-toothed spinosaurs suggests that several members of this dino group were predominantly aquatic, researchers report March 23 in Nature.

That finding is the latest salvo in an ongoing challenge to the prevailing view that all dinosaurs were land-based animals that left the realms of water and air to marine reptiles such as Mosasaurus and flying reptiles such as Pteranodon. But, other researchers say, it still doesn’t prove that Spinosaurus and its kin actually swam.
Back in 2014, Nizar Ibrahim, a vertebrate paleontologist now at the University of Portsmouth in England, and colleagues pieced together the fossil of a 15-meter-long Spinosaurus from what’s now Morocco. The dinosaur’s odd collection of features — a massive sail-like structure on its back, short and muscular legs, nostrils set well back from its snout and needlelike teeth seemingly designed for snagging fish — suggested to the researchers that the predator might have been a swimmer (SN: 9/11/14). In particular, it had very dense leg bones, a feature of some aquatic creatures like manatees that need the bones for ballast to stay submerged.

In the new study, Ibrahim and his team returned to that question of bone density to assess whether it’s a reliable proxy for how much time a creature spends in the water. The team assembled “a massive dataset” of femur and dorsal rib bone densities from “an incredible menagerie of extinct and living animals, reaching out to museum curators all around the world,” Ibrahim says.

That menagerie includes spinosaurs like showy, sail-backed Spinosaurus as well as its equally sharp-toothed cousins Baryonyx and Suchomimus. It also includes other groups of dinosaurs, extinct marine reptiles, pterosaurs, birds, modern crocodiles and marine mammals.

The team then compared these bone analyses with the water-dwelling habits of the various creatures in the study. That work confirms that density is “an excellent indicator” for species in the early stages of a transition from land-dwelling to water-dwelling, the team reports. Those compact bones can aid such transitional creatures, which might not yet have features like fins or flippers to help them maneuver in the water more easily, in hunting underwater — what the team calls “subaqueous foraging.”

The analyses also show that not only did Spinosaurus have very dense bones, but Baryonyx did too. That suggests that both of these dinos were subaqueous foragers, the team says. That idea builds on previous work by Ibrahim and colleagues that proposed that Spinosaurus didn’t just spend much of its time in the water, but could actually swim in pursuit of prey, thanks to its odd, paddle-shaped tail (SN: 4/29/20).
The idea of a swimming Spinosaurus hasn’t been convincing to all. In 2021, a study in Palaeontologia Electronica examined Spinosaurus’ anatomy in detail and came to a different conclusion. The dinosaur was not a highly specialized aquatic predator, wrote David Hone, a zoologist and paleobiologist at Queen Mary University of London, and Thomas Holtz Jr., a vertebrate paleontologist at the University of Maryland in College Park. Instead, Spinosaurus may have just waded in the shallows, heronlike, to do its fishing.

The new study has not convinced those skeptics. Spinosaurus has “clearly got very dense bones. This is really good evidence that they’re hanging around in water — but we kind of knew that,” Hone says. “It’s not clear what they’re doing in the water. That’s the contentious part.”

Take hippos, which spend much of their time mostly submerged, Hone says. “Hippos have bone densities entirely comparable to Spinosaurus and Baryonyx, but they don’t eat in the water” and they don’t swim, he adds.

“Everyone has been in agreement that Spinosaurus was more aquatic than other big theropods” like Tyrannosaurus rex, Holtz says. That Baryonyx also had dense bones was a bit of an interesting surprise, he adds.

But dense bones or not, Holtz says, “it still doesn’t turn them into aquatic hunters.” He describes several anatomical features — Spinosaurus’ long slender neck, tilted head and arrangement of neck muscles that suggest a downward striking motion — that point more to a wading creature that hunted from above the water surface than one that chased its prey underwater.

Kiersten Formoso, a vertebrate paleobiologist at the University of Southern California in Los Angeles, says that the new comparison of bone densities among a wide variety of creatures is a valuable addition, one that she anticipates referring to in her own work studying the transition of ancient creatures from land to water. But she too is not convinced that it proves that Spinosaurus and Baryonyx could actually swim.

“I would never detach Spinosaurus from the water,” Formoso says. But, she adds, more work needs to be done on its biomechanics — how it might have moved — to understand how adroitly aquatic the dinosaur might have been.

Earthquakes have rocked the planet for eons. Studying the quakes of old could help scientists better understand modern tremors, but tools to do such work are scarce.

Enter zircons. Researchers used the gemstones to home in on the temperatures reached within a fault during earthquakes millions of years ago. The method offers insights into the intensity of long-ago quakes, and could improve understanding of how today’s tremors release energy, the researchers report in the April Geochemistry, Geophysics, Geosystems.
“The more we understand about the past, the more we can understand what might happen in the future,” says Emma Armstrong, a thermochronologist at Utah State University in Logan.

Armstrong and colleagues focused on California’s Punchbowl Fault. That now-quiet portion of the larger San Andreas Fault was probably active between 1 million to 10 million years ago, Armstrong says.

Heat from friction is generated in a fault when it slips and triggers an earthquake. Previous analyses of preserved organic material suggested that temperatures within the Punchbowl Fault peaked between 465° Celsius and 1065° C. The researchers suspected that zircons in rocks from the fault could narrow that broad window.

Zircons often contain the radioactive chemical elements uranium and thorium, which decay to helium at a predictable rate (SN: 5/2/22). That helium then builds up in the crystals. But when a zircon is heated past a temperature threshold — the magnitude of which depends on the zircon’s composition — the accumulated helium escapes.

Measuring the amounts of the three elements in zircons from the fault suggests that the most intense earthquake generated temperatures lower than 800° C. That roughly halves the range previously reported. The finding provides clues to the amount of heat released by quakes, something difficult to measure for modern tremors because they often occur at great depths.

Armstrong plans to continue studying zircons, in the hopes of finding more ways to exploit them for details about ancient quakes.

In a large laboratory cage, a male mosquito carries a genetic weapon that could launch the destruction of his species. That loss could also mean the end of the parasite that causes malaria.

The weapon, a self-replicating bit of DNA known as a gene drive, is one of the most anticipated and controversial tools being developed to stop mosquitoes from spreading diseases like malaria to humans.

The gene drive interferes with the insects’ ability to reproduce. It wiped out captive populations of mosquitoes in eight to 12 generations (SN: 10/27/18, p. 6) in a small lab study. In 2021, the technology worked in the large cages in Terni, Italy, too. Within as little as five to 10 years, this gene drive could be ready to test in the wild.

The first experimental release could be rolled out in Burkina Faso, Mali, Ghana or Uganda. In those locations, researchers are working with a nonprofit research consortium called Target Malaria to develop the gene drive carriers along with other genetically engineered mosquitoes to fight malaria.

This research is driven by the idea that every tool available must be used to fight malaria, which sickened close to 241 million people in 2020 and killed 670,000 worldwide, mostly in Africa. Children 5 years old and younger accounted for about 80 percent of the continent’s malaria deaths, the World Health Organization says.

Because of malaria’s huge toll, large investments have been made to fight the disease, yielding preventive drugs, insecticide-treated bed nets and even malaria vaccines — one was recently recommended for use in sub-Saharan Africa (SN: 12/18/21 & 1/1/22, p. 32). These efforts are helping. But mosquitoes are developing resistance to insecticides, and some anti-malaria drugs may no longer work well.

“To go toward zero [cases], we need to have something that is transformational,” says Fredros Okumu, a mosquito biologist and director of science at Ifakara Health Institute in Tanzania.
Gene drives might be the transformational answer people are looking for. Researchers are still refining and testing the technology, which was first devised in 2015 (SN: 12/12/15, p. 16). Though other types of genetically altered mosquitoes have been released in Brazil, the United States and elsewhere, those altered genes spread slowly among wild populations (SN Online: 3/9/22). Gene drives could potentially spread to nearly ever member of a species quickly, forever altering the species or wiping it out.

But whether gene drives ever play a role in combating malaria may depend as much on social considerations as on science.

“A technology doesn’t work by technical strength alone. It works because it embeds into a social context,” says Ramya Rajagopalan, a social scientist at the University of California, San Diego. In the past, scientists “developed a technology in the lab, got it all set up and ready to go, and then you go to the stakeholders and say, ‘Hey, we have this great technology, do you want to use it?’ ”

If people reject that sort of offer, as has happened with some genetically modified crops, researchers often think, “If [the public] only knew enough about the technology, they’d be more accepting,” Rajagopalan says. But more often the failure comes because the researchers “don’t include community voices from the outset in the design and the implementation.”

Because of the possibility of forever altering ecosystems, the European Union has already said “no” to using gene drives there. But Africa is where a gene drive might one day help defeat malaria. Researchers are hoping to eventually release gene drives on the continent, but must first get public consensus. To that end, scientists are looking for ways to involve members of the public in research, and learn about local priorities and how to talk about the technology.

Rattling the cage
No one is ready to let mosquitoes carrying gene drives out of the lab yet. For now, researchers are doing tests with mosquitoes in captivity to get an idea of whether the technology will work as planned. In the Terni cage trials, scientists used small rooms, setting humidity levels, lighting and other characteristics to mimic some of the conditions the mosquitoes might encounter in the wild.

In cages almost 5 cubic meters big — about the size of a small dressing room — containing hundreds of Anopheles gambiae mosquitoes, scientists added male members of the same species that carried the engineered change to their DNA.

The gene drive used for this experiment is built on the molecular scissors known as CRISPR/Cas9. Male mosquitoes are engineered to carry the gene drive, which consists of instructions for making the DNA-cutting enzyme Cas9 and an RNA that guides the enzyme to the gene to be cut. When an engineered male mates with an unaltered female, Cas9 snips a gene called doublesex inside the fertilized egg. As the egg tries to repair the cut, the gene drive from the father’s doublesex gene is pasted over the copy of the gene inherited from the mother. So the offspring gets two copies of the gene drive, instead of one.

Normally, any particular version of a gene has a 50 percent chance of being passed from parent to offspring. But with the copy-and-paste CRISPR system, gene drive–carrying mosquitoes pass the drive to about 96 percent of male progeny and more than 99 percent of females. With that genetic cheat, the gene drive spreads rapidly through the population.
The doublesex gene is essential for the development of female mosquitoes. When the gene doesn’t work, “the mosquito itself doesn’t work,” says Ruth Müller, chief ecologist and entomologist at the Institute of Tropical Medicine in Antwerp, Belgium. The gene drive breaks the gene.

Female offspring that inherit two copies of a broken doublesex gene develop mouthparts and genitalia that are closer to the male form. Those females are sterile, and they cannot bite people with their malformed mouthparts. Unable to bite, those mosquitoes can’t transmit malaria-causing parasites from their bodies to humans.

In those naturelike cages in Terni, when gene drive–carrying mosquitoes were introduced, the populations died out in 245 to 311 days, researchers reported in July 2021 in Nature Communications. In two cages where no gene drive mosquitoes were added, mosquito populations lived normally to the end of the experiment.

This was the first proof that the gene drive might work under almost real-world conditions, says Müller, one of the study’s leaders. But there is still a lot to learn about drives, she says, including how they will affect mosquito populations in the wild, whether they can slow malaria’s spread and importantly, what the impact will be on other creatures in the environment.

Getting those answers will determine the feasibility of moving forward scientifically. They will also play a big role in whether the public agrees to releasing a tool that could intentionally drive a species toward extinction.
Considering all possibilities
While Müller’s and other Target Malaria science teams based in Africa, Europe and North America refine gene drives, other affiliated and independent groups are mapping out what releasing a gene drive could do to the planet. “Right now there are a lot of theoretical discussions,” Müller says. It’s important to gather data to “fill the debate with more facts” about the real risks and benefits, she says.

At least 46 theoretical harms could arise from the use of gene drives on mosquitoes, researchers reported in March 2021 in Malaria Journal. Those potential downsides include reductions in pollinators and other species directly or indirectly related to the disappearance of the mosquitoes. It’s possible that people could develop allergic reactions to the bite of mosquitoes carrying a single copy of the gene drive, or to fish that eat the altered mosquito larvae. There could be a decline in water quality caused by large numbers of mosquito larvae dying. There’s even a set of scenarios in which malaria cases increase if, for instance, mosquito species that are better malaria spreaders take over in areas where a gene drive has thinned out less-troublesome mosquitoes.

Dreaming up possible nightmare consequences was an exercise intended to tell researchers what they might need to plan for and test before releasing gene drive mosquitoes into the wild. At workshops held in 2016 through 2019 in Ghana, Kenya, Botswana, Gabon and the United States, researchers worked out a chain of events that might lead to each of those potential harms.

The list of 46 possibilities focused on four areas that African leaders said were most important to protect: biodiversity, human and animal health, and water quality. By identifying these hypothetical hazards, researchers can begin calculating the likelihood of a harm happening and how bad it could be, says report coauthor John Connolly, a senior regulatory scientist for Target Malaria who is based at Imperial College London.

“You probably never really finish a risk assessment, but you get a clearer understanding of the risks and uncertainties,” Connolly says. Target Malaria and independent groups hope to answer some questions by examining data collected from the release of genetically altered mosquitoes that don’t carry gene drives.

Studies of biological pest control mechanisms — such as releasing a predator to eradicate an invasive species (remember invasive cane toads in Australia [SN Online: 10/14/14]) — may also provide some clues about how gene drives may spread, says Keith Hayes, who leads a risk assessment team at the Commonwealth Science and Industrial Research Organization’s Data61 in Hobart, Australia.

Some questions may never truly be answered unless gene drives are released. Scientists can experiment and simulate what might happen, but “at some point you have to say, ‘We don’t know everything. We can’t know everything. There may be surprises,’ ” Hayes says. That’s when a decision will need to be made about a release based on what is known about the risks and benefits.

High stakes
Even if those evaluations reveal downsides to gene drives, the potential benefits for human health and economics may far outweigh the risks, Müller argues.

“If you have a high burden of malaria, that costs a lot,” Müller says. “Children cannot go to school. People cannot go to work. That should also be considered if you talk about costs.”

Opponents of gene drives say it’s unfair to paint rejection of the unproven, potentially dangerous, technology as dooming children to death from malaria. “We are already not saving those children with measures [that would help] such as improving sanitation and the medical system,” says Mareike Imken, the European coordinator of the Stop Gene Drives campaign. Her organization is calling for a global moratorium on the release of gene drives until there is worldwide consensus on whether they are safe and necessary and how they should be regulated.

“We need the highest possible obstacle to using this high-risk … technology,” Imken says. Allowing gene drives to be tried against malaria would essentially unleash them for use against a wide variety of organisms, with potentially devastating ecological consequences, she says. Instead, the world should invest more in already proven methods of controlling and eradicating malaria.

But there are potential upsides to gene drives that current approaches, such as insecticides, don’t offer. “The stuff we have been doing for years has been intentionally designed to eradicate mosquitoes. It just didn’t do it. We’ve been spraying the hell out of them for years, and in the process killing a lot of other nontarget organisms,” Okumu says.

By replacing insecticides, gene drives might help save insects including bees, butterflies and other pollinators. And gene drives are designed to eliminate only the mosquito species that are dangerous, Okumu says. “Of all the 3,500 species … we need to target one, two, at maximum three of them.”

He’s referring to the handful of species in the Anopheles genus that are mostly responsible for spreading malaria. In Africa, the primary disease carriers are Anopheles gambiae and the look-alikes An. arabiensis, An. coluzzii and An. funestus.

While eradicating malaria is the goal, making mosquitoes extinct is mostly hyperbole, says Tony Nolan, a molecular biologist at the Liverpool School of Tropical Medicine in England.

“Extinction is not a likely outcome, nor even a desirable one. It’s not necessary to make the mosquito extinct to eliminate malaria,” says Nolan, one of the Target Malaria researchers developing gene drives. Geographic isolation may enable the gene drive to eliminate a local population of mosquitoes but nothing further afield. Mutations can arise in the Cas9 or guide RNA, causing the drive to stop working. Or other things might limit its spread.

But what would happen to the environment if a major mosquito species suddenly disappeared? Some researchers are trying to measure the ecological contributions of An. gambiae, including whether males pollinate plants visited for nectar. As of now, the mosquitoes’ biggest known value is as food for predators. Birds, fish and other animals that eat mosquitoes or their larvae usually aren’t picky about which species is for dinner. Only one species of spider is known to prefer Anopheles mosquitoes over other kinds.

Okumu’s experience leads him to think the malaria carriers wouldn’t be missed much. In some parts of eastern Africa, including Okumu’s home village in Tanzania, a combination of factors including prolonged dry seasons and insecticide and bed net use pushed An. gambiae out. “We have not seen — maybe because we didn’t measure [well enough] — any ecological challenges associated with the disappearance of Anopheles gambiae,” he says.

The mix of malaria carriers can vary considerably depending on local conditions. In Burkina Faso in western Africa, for instance, two villages had different mosquito populations: In Bana, to the northwest of the city Bobo­-Dioulasso, about 90 percent of mosquitoes were An. coluzzii with An. gambiae making up 9 percent of the catch, researchers reported in 2019 in Malaria Journal. But on the southeastern side of the city, in the village of Pala, An. gambiae dominated, making up about 84 percent of mosquitoes caught. An. arabiensis accounted for about 10 percent, and An. coluzzii was about 6 percent of the catch in Pala.

If An. gambiae disappeared, one of the other species would fill the vacuum, Okumu says. That could be a good thing if the replacements don’t bite people as much or are lousy at spreading malaria. It could also be worse if the balance shifts toward a more voracious people-biter that easily spreads the parasites.
Community input
Beyond the scientific hurdles, researchers must also get the public on board with releasing the technology. Without public support, even a gene drive that works perfectly could be a no-go.

Not everyone agrees on when and how to get input. Okumu worries that asking the public whether they want gene drives before scientists have answers to some of the most pressing questions could backfire. “I would rather we know the true benefits, the true risks and gain a consensus around it, and then start engaging the communities,” he says.

Waiting until all the answers are in hand is a flawed approach, says Lea Pare Toe, a social scientist at the Institut de Recherche en Sciences de la Santé in Bobo-Dioulasso. “We should listen to [the community] and develop the science together,” says Toe, who works with Target Malaria to engage local people in the research.

At Bana, researchers didn’t start out talking about gene drives, or even genetic modifications, Toe says. First, the team had to clarify the connection between mosquitoes and malaria. They also had to dispel myths, such as eating fatty foods or sweet fruit can cause the disease. After an intensive engagement campaign from 2014 through 2019, researchers found that such false statements were far less accepted, the researchers reported in October 2021 in Malaria Journal.
Once people are clear on the causes of malaria, Toe and colleagues introduce the idea of genetics, and how researchers want to alter mosquitoes to combat malaria. People are generally OK with the uncertainty of research, she says. But they want to know more.

Residents pose specific questions about mosquito biology and ask how researchers can possibly work with such small creatures. They often ask whether the genetic alterations that make the mosquitoes sterile will transfer to humans. People “love the details,” Toe says.

Sometimes, creative approaches are needed to get concepts across. For instance, Target Malaria planned a first stage — releasing genetically sterilized male mosquitoes that won’t diminish mosquito populations — to help researchers collect data on how genetically altered mosquitoes stack up to normal ones in the wild.

Before those altered mosquitoes were set free, the organization wanted to ensure that Bana residents had a deep understanding of the project. Local leaders suggested a play. The scientists wrote a script, but the actors, a local storyteller and other community members revised it to improve storytelling. This helped forge an emotional connection with the audience, Toe and colleagues reported April 5 in Humanities and Social Sciences Communications.
Meanwhile in Tanzania, although reluctant to move too soon with the public, Okumu and colleagues talked with community leaders and surveyed residents of 10 villages in the southeastern part of the country, where very few people had heard about genetically modifying mosquitoes. The aim of this 2019 effort was to understand community perceptions, rather than ask permission. People were intrigued by the idea of gene drives, but they had concerns about whether the mosquitoes would look and behave differently from local mosquitoes, the team reported in March 2021 in Malaria Journal.

Community members were also skeptical that targeting just one type of mosquito would be enough to reduce malaria transmission or decrease mosquito bites enough to keep communities on board with the project. It would be better, they said, to get rid of all the biting mosquitoes.

In a separate study done in 2019, people in Uganda who were already familiar with gene drives expressed similar concerns. But those participants anticipated problems if the mosquitoes cross national borders into a country opposed to the release, researchers reported in March 2021 in Malaria Journal. Researchers may have to seek permission to release gene drive mosquitoes on a multinational scale, instead of just getting local and national consent.

Gene drives may win hearts and minds because they will first be tried against disease-carrying mosquitoes “that are very, very much not beloved or charismatic or anything,” says developmental geneticist Kimberly Cooper of UC San Diego. “Do you know anyone who has sympathies for the mosquito? It’s probably the most hated animal on the planet.

“But there will always be people who are very concerned about genetically modified organisms and their release into the environment,” even if those organisms are mosquitoes, says Cooper, who is not involved with the malaria gene drive research but is developing a gene drive to use as a research tool in mice (SN Online: 1/23/19).

Still, the attraction of stamping out malaria is powerful. The benefits could be enormous. But whether they outweigh any environmental risks from the technology and whether the public will buy in to this radical approach remains to be seen.

“There are tons of unknowns,” Okumu says. “The question is, should we pursue it? If you ask me, it would be unethical not to.”

It turns out that chicken and rice may have always gone together, from the birds’ initial domestication to tonight’s dinner.

In two new studies, scientists lay out a potential story of chicken’s origins. This poultry tale begins surprisingly recently in rice fields planted by Southeast Asian farmers around 3,500 years ago, zooarchaeologist Joris Peters and colleagues report. From there, the birds were transported westward not as food but as exotic or culturally revered creatures, the team suggests June 6 in the Proceedings of the National Academy of Sciences.
“Cereal cultivation may have acted as a catalyst for chicken domestication,” says Peters, of Ludwig Maximilian University of Munich.

The domesticated fowl then arrived in Mediterranean Europe no earlier than around 2,800 years ago, archaeologist Julia Best of Cardiff University in Wales and colleagues report June 6 in Antiquity. The birds appeared in northwest Africa between 1,100 and 800 years ago, the team says.

Researchers have debated where and when chickens (Gallus gallus domesticus) originated for more than 50 years. India’s Indus Valley, northern China and Southeast Asia have all been touted as domestication centers. Proposed dates for chickens’ first appearance have mostly ranged from around 4,000 to 10,500 years ago. A 2020 genetic study of modern chickens suggested that domestication occurred among Southeast Asian red jungle fowl. But DNA analyses, increasingly used to study animal domestication, couldn’t specify when domesticated chickens first appeared (SN: 7/6/17).

Using chicken remains previously excavated at more than 600 sites in 89 countries, Peters’ group determined whether the chicken bones had been found where they were originally buried by soil or, instead, had moved downward into older sediment over time and thus were younger than previously assumed.

After establishing the timing of chickens’ appearances at various sites, the researchers used historical references to chickens and data on subsistence strategies in each society to develop a scenario of the animals’ domestication and spread.

The new story begins in Southeast Asian rice fields. The earliest known chicken remains come from Ban Non Wat, a dry rice–farming site in central Thailand that roughly dates to between 1650 B.C. and 1250 B.C. Dry rice farmers plant the crop on upland soil soaked by seasonal rains rather than in flooded fields or paddies. That would have made rice grains at Ban Non Wat fair game for avian ancestors of chickens.

These fields attracted hungry wild birds called red jungle fowl. Red jungle fowl increasingly fed on rice grains, and probably grains of another cereal crop called millet, grown by regional farmers, Peters’ group speculates. A cultivated familiarity with people launched chicken domestication by around 3,500 years ago, the researchers say.

Chickens did not arrive in central China, South Asia or Mesopotamian society in what’s now Iran and Iraq until nearly 3,000 years ago, the team estimates.

Peters and colleagues have for the first time assembled available evidence “into a fully coherent and plausible explanation of not only where and when, but also how and why chicken domestication happened,” says archaeologist Keith Dobney of the University of Sydney who did not participate in the new research.

But the new insights into chickens don’t end there. Using radiocarbon dating, Best’s group determined that 23 chicken bones from 16 sites in Eurasia and Africa were generally younger, in some cases by several thousand years, than previously thought. These bones had apparently settled into lower sediment layers over time, where they were found with items made by earlier human cultures.
Archaeological evidence indicates that chickens and rice cultivation spread across Asia and Africa in tandem, Peters’ group says. But rather than eating early chickens, people may have viewed them as special or sacred creatures. At Ban Non Wat and other early Southeast Asian sites, partial or whole skeletons of adult chickens were placed in human graves. That behavior suggests chickens enjoyed some sort of social or cultural significance, Peters says.

In Europe, several of the earliest chickens were buried alone or in human graves and show no signs of having been butchered.

The expansion of the Roman Empire around 2,000 years ago prompted more widespread consumption of chicken and eggs, Best and colleagues say. In England, chickens were not eaten regularly until around 1,700 years ago, primarily at Roman-influenced urban and military sites. Overall, about 700 to 800 years elapsed between the introduction of chickens in England and their acceptance as food, the researchers conclude. Similar lag times may have occurred at other sites where the birds were introduced.