A simulation built using data from honeybees suggests that large locust swarms, like the one pictured here, could produce as much electricity as a storm cloud.
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.
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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.”
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Aye-ayes aren’t the most photogenic creatures under the best of circumstances. But caught in the dead of night, hunched over with several centimeters of finger stuck up its nose, this bizarre primate looks positively haunting.
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 .
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“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.
Previously the staff writer for physical sciences at Science News , Maria Temming is the assistant editor at Science News Explores . She has bachelor’s degrees in physics and English, and a master’s in science writing.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Like the rubbery nubs on the bottom of baby socks, microstructures on the bears’ paw pads offer some extra friction, scientists report November 1 in the Journal of the Royal Society Interface . The pad protrusions may keep polar bears from slipping on snow, says Ali Dhinojwala, a polymer scientist at the University of Akron in Ohio who has also studied the sticking power of gecko feet ( SN: 8/9/05 ).
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Nathaniel Orndorf, a materials scientist at Akron who focuses on ice, adhesion and friction, was interested in the work Dhinojwala’s lab did on geckos, but “we can’t really put geckos on the ice,” he says. So he turned to polar bears.
Orndorf teamed up with Dhinojwala and Austin Garner, an animal biologist now at Syracuse University in New York, and compared the paws of polar bears, brown bears, American black bears and a sun bear. All but the sun bear had paw pad bumps. But the polar bears’ bumps looked a little different. For a given diameter, their bumps tend to be taller, the team found. That extra height translates to more traction on lab-made snow, experiments with 3-D printed models of the bumps suggest.
Until now, scientists didn’t know that bump shape could make the difference between gripping and slipping, Dhinojwala says.
Polar bear paw pads are also ringed with fur and are smaller than those of other bears, the team reports, adaptations that might let the Arctic animals conserve body heat as they trod upon ice. Smaller pads generally mean less real estate for grabbing the ground. So extra-grippy pads could help polar bears make the most of what they’ve got, Orndorf says.
Along with bumpy pads, the team hopes to study polar bears’ fuzzy paws and short claws, which might also give the animals a nonslip grip.
Meghan Rosen is a staff writer who reports on the life sciences for Science News . She earned a Ph.D. in biochemistry and molecular biology with an emphasis in biotechnology from the University of California, Davis, and later graduated from the science communication program at UC Santa Cruz.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
The first of King Tutankhamun’s three nested coffins is shown on September 21, 2019, awaiting restoration in a lab at the new Grand Egyptian Museum outside Cairo.
One hundred years ago, archaeologist Howard Carter stumbled across the tomb of ancient Egypt’s King Tutankhamun. Carter’s life was never the same. Neither was the young pharaoh’s afterlife.
Newspapers around the world immediately ran stories about Carter’s discovery of a long-lost pharaoh’s grave and the wonders it might contain, propelling the abrasive Englishman to worldwide acclaim. A boy king once consigned to ancient obscurity became the most famous of pharaohs ( SN: 12/18/76 ).
It all started on November 4, 1922, when excavators led by Carter discovered a step cut into the valley floor of a largely unexplored part of Egypt’s Valley of the Kings. By November 23, the team had uncovered stairs leading down to a door. A hieroglyphic seal on the door identified what lay beyond: King Tutankhamun’s tomb.
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Tutankhamun assumed power around 1334 B.C., when he was about 10 years old. His reign lasted nearly a decade until his untimely demise. Although a minor figure among Egyptian pharaohs, Tutankhamun is one of the few whose richly appointed burial place was found largely intact.
An unusually meticulous excavator for his time, Carter organized a 10-year project to document, conserve and remove more than 6,000 items from Tutankhamun’s four-chambered tomb. While some objects, like Tut’s gold burial mask, are now iconic, many have been in storage and out of sight for decades. But that’s about to change. About 5,400 of Tutankhamun’s well-preserved tomb furnishings are slated to soon go on display when the new Grand Egyptian Museum , near the Pyramids of Giza, opens.
“The [Tut] burial hoard is something very unique,” Shirin Frangoul-Brückner, managing director of Atelier Brückner in Stuttgart, Germany, the firm that designed the museum’s Tutankhamun Gallery, said in an interview released by her company. Among other items, the exhibit will include the gold burial mask, musical instruments, hunting equipment, jewelry and six chariots.
Even as more of Tut’s story is poised to come to light, here are four things to know on the 100th anniversary of his tomb’s discovery.
Tutankhamun has a reputation as a fragile young man who limped on a clubfoot. Some researchers suspect a weakened immune system set him up for an early death.
But “recent research suggests it’s wrong to portray Tut as a fragile pharaoh,” says Egyptologist and mummy researcher Bob Brier, who is an expert on King Tut. His new book Tutankhamun and the Tomb That Changed the World chronicles how 100 years of research have shaped both Tut’s story and archaeology itself.
Clues from Tutankhamun’s mummy and tomb items boost his physical standing, says Brier, of Long Island University in Brookville, N.Y. The young pharaoh might even have participated in warfare.
Military chariots, leather armor and archery equipment buried with Tutankhamun show that he wanted to be viewed as a hunter and a warrior, Brier says. Inscribed blocks from Tutankhamun’s temple, which were reused in later building projects before researchers identified them, portray the pharaoh leading charioteers in undated battles.
If more blocks turn up showing battle scenes marked with dates, it would suggest Tutankhamun probably participated in those conflicts, Brier says. Pharaohs typically recorded dates of actual battles depicted in their temples, though inscribed scenes may have exaggerated their heroism.
The frail story line has been built in part on the potential discovery of a deformity in Tut’s left foot, along with 130 walking sticks found in his tomb. But ancient Egyptian officials were often depicted with walking sticks as signs of authority, not infirmity, Brier says. And researchers’ opinions vary about whether images of Tut’s bones reveal serious deformities.
X-rays of the recovered mummy from the 1960s show no signs of a misshapen ankle that would have caused a limp. Neither did CT images examined in 2005 by the Egyptian Mummy Project, headed by Egyptologist and former Egyptian Minister of Antiquities Zahi Hawass.
Then a 2009 reexamination of the CT images by the same researchers indicated that Tutankhamun had a left-foot deformity generally associated with walking on the ankle or the side of the foot, the team reported. The team’s radiologist, Sahar Saleem of Egypt’s Cairo University, says the CT images show that Tutankhamun experienced a mild left clubfoot, bone tissue death at the ends of two long bones that connect to the second and third left toes and a missing bone in the second left toe.
Those foot problems would have “caused the king pain when he walked or pressed his weight on his foot, and the clubfoot must have caused limping,” Saleem says. So a labored gait, rather than an appeal to royal authority, could explain the many walking sticks placed in Tutankhamun’s tomb, she says.
Brier, however, doubts that scenario. Tutankhamun’s legs appear to be symmetrical in the CT images, he says, indicating that any left foot deformity was too mild to cause the pharaoh regularly to put excess weight on his right side while walking.
Whether or not the boy king limped through life, the discovery and study of his mummy made it clear that he died around age 19, on the cusp of adulthood. Yet Tut’s cause of death still proves elusive.
In a 2010 analysis of DNA extracted from the pharaoh’s mummy, Hawass and colleagues contended that malaria, as well as the tissue-destroying bone disorder cited by Saleem from the CT images, hastened Tutankhamun’s death. But other researchers, including Brier, disagree with that conclusion. Further ancient DNA studies using powerful new tools for extracting and testing genetic material from the mummy could help solve that mystery.
After Tutankhamun’s death, ancient Egyptian officials did their best to erase historical references to him. His reign was rubbed out because his father, Akhenaten, was a “heretic king” who alienated his own people by banishing the worship of all Egyptian gods save for one.
“Akhenaten is the first monotheist recorded in history,” Brier says. Ordinary Egyptians who had prayed to hundreds of gods suddenly could worship only Aten, a sun god formerly regarded as a minor deity.
Meeting intense resistance to his banning of cherished religious practices, Akhenaten — who named himself after Aten — moved to an isolated city, Amarna, where he lived with his wife Nefertiti, six girls, one boy and around 20,000 followers. After Akhenaten died, residents of the desert outpost returned to their former homes. Egyptians reclaimed their old-time religion. Akhenaten’s son, Tutankhaten — also originally named after Aten — became king, and his name was changed to Tutankhamun in honor of Amun, the most powerful of the Egyptian gods at the time.
Later pharaohs omitted from written records any mentions of Akhenaten and Tutankhamun. Tut’s tomb was treated just as dismissively. Huts of craftsmen working on the tomb of King Ramses VI nearly 200 years after Tut’s death were built over the stairway leading down to Tutankhamun’s nearby, far smaller tomb. Limestone chips from the construction littered the site.
The huts remained in place until Carter showed up. While Carter found evidence that the boy king’s tomb had been entered twice after it was sealed, whoever had broken in took no major objects.
“Tutankhamun’s ignominy and insignificance saved him” from tomb robbers, says UCLA Egyptologist Kara Cooney.
Pharaohs usually prepared their tombs over decades, building many rooms to hold treasures and extravagant coffins. Egyptian traditions required the placement of a mummified body in a tomb about 70 days after death. That amount of time may have allowed a mummy to dry out sufficiently while retaining enough moisture to fold the arms across the body inside a coffin, Brier suspects.
Because Tutankhamun died prematurely, he had no time for extended tomb preparations. And the 70-day burial tradition gave craftsmen little time to finish crucial tomb items, many of which required a year or more to make. Those objects include a carved stone sarcophagus that encased three nested coffins, four shrines, hundreds of servant statues, a gold mask, chariots, jewelry, beds, chairs and an alabaster chest that contained four miniature gold coffins for Tutankhamun’s internal organs removed during mummification.
Evidence points to workers repurposing many objects from other people’s tombs for Tutankhamun. Even then, time ran out.
Consider the sarcophagus. Two of four goddesses on the stone container lack fully carved jewelry. Workers painted missing jewelry parts. Carved pillars on the sarcophagus are also unfinished.
Tutankhamun’s granite sarcophagus lid, a mismatch for the quartzite bottom, provides another clue to workers’ frenzied efforts. Something must have happened to the original quartzite lid, so workers carved a new lid from available granite and painted it to look like quartzite, Brier says.
Repairs on the new lid indicate that it broke in half during the carving process. “Tutankhamun was buried with a cracked, mismatched sarcophagus lid,” Brier says.
Tutankhamun’s sarcophagus may originally have been made for Smenkare, a mysterious individual who some researchers identify as the boy king’s half brother. Little is known about Smenkare, who possibly reigned for about a year after Akhenaten’s death, just before Tutankhamun, Brier says. But Smenkare’s tomb has not been found, leaving the sarcophagus puzzle unsolved.
Objects including the young king’s throne, three nested coffins and the shrine and tiny coffins for his internal organs also contain evidence of having originally belonged to someone else before being modified for reuse, says Harvard University archaeologist Peter Der Manuelian.
Even Tutankhamun’s tomb may not be what it appears. Egyptologist Nicholas Reeves of the University of Arizona Egyptian Expedition in Tucson has argued since 2015 that the boy king’s burial place was intended for Nefertiti. He argues that Nefertiti briefly succeeded Akhenaten as Egypt’s ruler and was the one given the title Smenkare.
No one has found Nefertiti’s tomb yet. But Reeves predicts that one wall of Tutankhamun’s burial chamber blocks access to a larger tomb where Nefertiti lies. Painted scenes and writing on that wall depict Tutankhamun performing a ritual on Nefertiti’s mummy, he asserts. And the gridded structure of those paintings was used by Egyptian artists years before Tutankhamun’s burial but not at the time of his interment.
But four of five remote sensing studies conducted inside Tutankhamun’s tomb have found no evidence of a hidden tomb. Nefertiti, like Smenkare, remains a mystery.
Carter’s stunning discovery occurred as Egyptians were protesting British colonial rule and helped fuel that movement. Among the actions that enraged Egyptian officials: Carter and his financial backer, a wealthy British aristocrat named Lord Carnarvon, sold exclusive newspaper coverage of the excavation to The Times of London. Things got so bad that Egypt’s government locked Carter out of the tomb for nearly a year, starting in early 1924.
Egyptian nationalists wanted political independence — and an end to decades of foreign adventurers bringing ancient Egyptian finds back to their home countries. Tutankhamun’s resurrected tomb pushed Egyptian authorities toward enacting laws and policies that helped to end the British colonial state and reduce the flow of antiquities out of Egypt, Brier says, though it took decades. Egypt became a nation totally independent of England in 1953. A 1983 law decreed that antiquities could no longer be taken out of Egypt (though those removed before 1983 are still legal to own and can be sold through auction houses).
In 1922, however, Carter and Lord Carnarvon regarded many objects in Tutankhamun’s tomb as theirs for the taking, Brier says. That was the way that Valley of the Kings excavations had worked for the previous 50 years, in a system that divided finds equally between Cairo’s Egyptian Museum and an expedition’s home institution. Taking personal mementos was also common.
Evidence of Carter’s casual pocketing of various artifacts while painstakingly clearing the boy king’s tomb continues to emerge. “Carter didn’t sell what he took,” Brier says. “But he felt he had a right to take certain items as the tomb’s excavator.”
Recently recovered letters of English Egyptologist Alan Gardiner from the 1930s, described by Brier in his book, recount how Carter gave Gardiner several items from Tutankhamun’s tomb, including an ornament used as a food offering for the dead. French Egyptologist Marc Gabolde of Paul-Valéry Montpellier 3 University has tracked down beads, jewelry, a headdress fragment and other items taken from Tutankhamun’s tomb by Carter and Carnarvon.
Yet it is undeniable that one of Tutankhamun’s greatest legacies, thanks to Carter, is the benchmark the excavation of his tomb set for future excavations, Brier says. Carter started his career as an artist who copied painted images on the walls of Egyptian tombs for excavators. He later learned excavation techniques in the field working with an eminent English Egyptologist, Flinders Petrie. Carter took tomb documentation to a new level, rounding up a crack team consisting of a photographer, a conservator, two draftsmen, an engineer and an authority on ancient Egyptian writing.
Their decade-long effort also made possible the new Tutankhamun exhibition at the Grand Egyptian Museum. Now, not only museum visitors but also a new generation of researchers will have unprecedented access to the pharaoh’s tomb trove.
“Most of Tutankhamun’s [tomb] objects have been given little if any study beyond what Carter was able to do,” says UCLA’s Cooney.
That won’t be true for much longer, as the most famous tomb in the Valley of the Kings enters the next stage of its public and scientific afterlife.
Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Radiation-tolerant bacteria similar to this Deinococcus radiodurans would be particularly well-suited to surviving Mars’ harsh, freezing environment, a new study suggests.
Radiation-tolerant microbes might be able to live beneath Mars’ surface for hundreds of millions of years and may yet persist today, thanks in part — counterintuitively — to the Red Planet’s frigid, arid conditions.
In addition to being cold and dry, the Martian surface is constantly bombarded by cosmic rays, charged particles and other radiation from space. Previous studies have shown that desiccation vastly extends a microbe’s potential for surviving by limiting the production of highly reactive oxygen-bearing chemicals that can damage proteins and DNA, among other vital molecules within its tissues. To see how long microbes might survive such an onslaught on Mars, researchers desiccated five species of bacteria and one type of yeast, stored them at −80° Celsius and then irradiated them.
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Some of the microbes might remain viable for only a few tens of thousands of years, experiments showed. But one species — Deinococcus radiodurans , a particularly radiation-hardy greebly that some scientists have nicknamed “Conan the bacterium” — might survive for as long as 280 million years if protected from radiation at soil depths of 10 meters or more , physical chemist Brian Hoffman and colleagues report online October 25 in Astrobiology .
D. radiodurans resists radiation damage by having multiple copies of chromosomes and other genetic material in each cell, as well as high levels of manganese-bearing antioxidants that help remove DNA-damaging chemicals ( SN: 9/3/10 ). If similar microbes evolved on Mars, they too could persist for lengthy intervals, even possibly until now — which is “improbable but not impossible,” says Hoffman, of Northwestern University in Evanston, Ill.
Even if microbes that evolved on Mars ultimately succumbed to the harsh conditions, remnants of their proteins or other macromolecules may remain — offering hope that future missions, if equipped with the proper equipment, might be able to detect those signs of former life.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
In early 2022, malaria cases in the Ethiopian city of Dire Dawa surged, with more than 2,400 people sickened. The spike in infections was the work of an invasive mosquito species that’s spreading across Africa, scientists report.
The finding, presented November 1 in Seattle at the annual meeting of the American Society of Tropical Medicine and Hygiene, provides evidence that the invasive vector can drive malarial outbreaks . Worryingly, the species can thrive in urban environments, bringing the threat of malaria to potentially many millions more people across the continent.
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Anopheles stephensi is a mosquito native to India and the Persian Gulf, where it is a major vector for the Plasmodium parasites that cause malaria in people ( SN: 10/26/20 ). In Africa, the primary malaria vector is Anopheles gambiae . A. stephensi was first reported on the African continent in Djibouti in 2012. Since then, the species has turned up in other African countries such as Ethiopia, Somalia and Nigeria.
It wasn’t clear what kind of malarial burden the invasive mosquito could bring to Africa, says Fitsum Girma Tadesse, a molecular biologist at the Armauer Hansen Research Institute in Addis Ababa, Ethiopia. In the eight years after the mosquito’s arrival in Djibouti, the country reported a 40-fold increase in yearly malaria cases, Tadesse says. But no one had directly linked A. stephensi to the increase.
So when malaria cases suddenly rose in Dire Dawa — from 27 cases to 260 in just three weeks in early 2022 — Tadesse and his team jumped in to investigate.
The researchers tracked 80 patients in the city who had sought care for malaria at a local or university clinic, as well as 210 patients who had sought treatment for other reasons, and they screened the patients’ household members for malaria. The team also scanned the patients’ neighborhoods for the presence of mosquito adults and larvae within a 100-meter radius of households, or in the cases of students that visited a clinic, dormitories.
The team found that the malaria patients primarily lived near water sources used by the invasive mosquito, A. stephensi . Households and dorms close to aquatic habitats harboring A. stephensi larvae were 3.4 times as likely as those not close to such water sources to have a family or dorm member test positive for malaria. And most of the adult mosquitoes the team caught — 97 percent — were of the invasive species, the only mosquito species that the researchers found carrying Plasmodium parasites.
A. stephensi “prefers to breed in water storage containers that are typically common in rapidly expanding urban settings,” Tadesse says. The native mosquito species, A. gambiae , tends to use natural sources of water like small pools, which are more common in rural regions, he adds. The concern, then, is that with the expansion of A. stephensi alongside urbanization in Africa, the mosquito could exploit many new sources of water stores.
“This expands the malaria problem from a predominantly rural problem to an urban problem,” says Teun Bousema, an epidemiologist at Radboud University in Nijmegen, the Netherlands.
“The spread of Anopheles stephensi is concerning because this species has a number of characteristics that make it difficult to control,” says Tanya Russell, a medical entomologist at James Cook University in Townsville, Australia, who was not involved in the study. Not only can the insects lay their eggs in nearly any available water source, but also the eggs can survive being dry for long periods of time. “This is very uncharacteristic for malaria vectors.”
Insecticide-treated bed nets and spraying a residual insecticide indoors are the primary vector control approaches for malaria-carrying mosquitoes, Russell says. But since A. stephensi also bites outdoors, the mosquito’s spread may blunt the efficacy of these tools.
The key next steps, Tadesse says, are interventions to reduce transmission of the deadly parasites, including targeting the mosquito’s larval phase with chemicals and encouraging communities to cover and secure water containers to prevent mosquitoes from laying eggs in them.
“The window of opportunity to do something about this species is closing,” Bousema says. “So, I really think this calls for very urgent action.”
Jake Buehler is a freelance science writer, covering natural history, wildlife conservation and Earth’s splendid biodiversity, from salamanders to sequoias. He has a master’s degree in zoology from the University of Hawaii at Manoa.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
