Scientists Discover "Zombie" Fungus That Seizes Control of Spiders, Suggest It Be Used for Human Medicine
In a study published last month in the journal Fungal Systematics and Evolution, as spotted by Live Science, scientists detailed the discovery of a "novel species" of fungus that infects "cave-dwelling, orb-weaving spiders," called Gibellula attenboroughii — a name in honor of British biologist and natural historian David Attenborough.
The scientists concluded that the "infected spiders exhibit behavioral changes similar to those reported for zombie ants," referring to an insect-pathogenic fungus that forces infected ants to leave their canopy nests and head to areas that are more suitable for fungal growth.
The way G. attenboroughii spreads is just as chill-inducing. The study authors suggest the fungus forces the infected spiders to crawl to more open areas where air currents can then disperse the spores — a fascinating new discovery fit for a dystopian TV series.
Study lead author and Center for Agriculture and Bioscience International researcher Harry Evans told Live Science that the spores penetrate the spider to infect the insect's equivalent of blood, compelling it to find open space. Then, a neurotoxin kills the spider once it reaches a spot in the open. An antimicrobial substance also preserves the corpse, allowing the fungus to absorb its nutrients.
The cycle then repeats with the fungus growing long — and terrifying-looking — structures out of the spider's body.
Despite the frightening optics, Evans told Live Science the substances the fungus produces could be a "medical treasure chest" with a range of possible applications in human medicine, including antibiotics.
More generally, the discovery highlights how much there's still to cover in the wild world of "zombie" fungi.
"There's a lot more fungi to find," Evans told Live Science. "The fungal kingdom could be up to 10, 20 million species, making it the biggest kingdom by far, but only one percent have been described."
More on fungi: Obscure Fungus Shows Signs of Rudimentary Intelligence
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5 hours ago
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What was the first human species?
When you buy through links on our articles, Future and its syndication partners may earn a commission. All humans today are members of the modern human species Homo sapiens — Latin for "knowing man." But we're far from the only humans who ever existed. Fossils are revealing more and more about early humans in the genus Homo — ancestors like Homo erectus (Latin for "upright man"), who lived in Africa, Asia and parts of Europe between 1.9 million and 110,000 years ago. Scientists now recognize more than a dozen species in the Homo genus. So what, exactly, was the first human species? The answer, it turns out, is not crystal clear. Fossil finds in Morocco have revealed that anatomically modern humans emerged at least 300,000 years ago. But the oldest human species scientists definitively know about is called Homo habilis, or "handy man" — a tool-using primate who walked upright and lived in Africa between 2.4 million and 1.4 million years ago. However, earlier fossils hint that other Homo species may predate H. habilis. The scarcity of early human fossils makes it challenging to know if unusual specimens are a newfound species or simply an atypical member of a known species. On top of that, evolution can be gradual, so it's hard to pinpoint when a new species emerges, especially when fossils have a mix of features from different species. "The process of evolution is continuous, but the labels we place on it for convenience are static," Tim D. White, a paleoanthropologist at the University of California Berkeley, told Live Science. Related: Why did Homo sapiens outlast all other human species? Earliest Homo Most evolutionary theories suggest that H. habilis evolved from an earlier genus of primate named Australopithecus — Latin for "southern ape" because its fossils were first discovered in South Africa. Sign up for our newsletter Sign up for our weekly Life's Little Mysteries newsletter to get the latest mysteries before they appear online. Various species of Australopithecus lived from about 4.4 million to 1.4 million years ago. It may be that H. habilis evolved directly from the species Australopithecus afarensis — the best-known example of which is "Lucy," who was unearthed at Hadar in Ethiopia in 1974. The fossils of our genus are usually distinguished from Australopithecus fossils by Homo's distinctively smaller teeth and a relatively large brain, which led to the greater use of stone tools. But White noted that traits like smaller teeth and bigger brains must have emerged at times in the Australopithecus populations that early Homo evolved from. "If you had an Australopithecus female, there wasn't a birth at which point she would have christened the child Homo," he said. As a result, there is no fixed point in time in which Homo originated; instead, the Homo genus emerged roughly between 2 million and 3 million years ago, White said. Evolving in Africa Since the 1970s, researchers in Africa have discovered fossils that they've attributed to another ancient species, Homo rudolfensis, which challenges the idea that H. habilis was the earliest Homo. H. rudolfensis seems to have been physically much bigger, had a larger brain and a flatter facial structure than H. habilis, which may have made it look more like a modern human. Its fossils are roughly the same age as H. habilis — as much as 2.4 million years old. But "there is only one really good fossil of this Homo rudolfensis," according to the Smithsonian National Museum of Natural History, so scientists don't know if H. rudolfensis is an unusual H. habilis or even an Austrolopithicus with a larger-than-usual brain. Paleoanthropologist Rick Potts, who heads the Smithsonian Institute's Human Origins program, told Live Science that even older fossils from Africa appear to be from the genus Homo and may predate both of those species. RELATED MYSTERIES —What did the last common ancestor between humans and apes look like? —Are Neanderthals and Homo sapiens the same species? —Why did Homo sapiens emerge in Africa? The oldest of those fossils date from about 2.8 million years ago, but they are only fragments — a few jaw bones and a few teeth — so they are not enough to establish if they came from a different, unnamed species of Homo, he said. A 2025 study found additional teeth dating to 2.59 million and 2.78 million years old that may also belong to this mysterious early Homo species. So it may be that the first human species has not yet been found. "There's a whole lot of excitement, but there is also a lot of uncertainty, about trying to discover more about the origins of the genus Homo," Potts said. Human evolution quiz: What do you know about Homo sapiens? Solve the daily Crossword
Scientific American
12 hours ago
- Scientific American
How Scientists Finally Learned That Nerves Regrow
Billions of nerve cells send signals coursing through our bodies, serving as conduits through which the brain performs its essential functions. For millennia physicians thought damage to nerves was irreversible. In ancient Greece, founders of modern medicine such as Hippocrates and Galen refused to operate on damaged nerves for fear of causing pain, convulsions or even death. The dogma stood relatively still until the past two centuries, during which surgeons and scientists found evidence that neurons in the body and brain can repair themselves and regenerate after injury and that new nerve cells can grow throughout the lifespan. In recent decades this knowledge has inspired promising treatments for nerve injuries and has led researchers to investigate interventions for neurodegenerative disease. In humans and other vertebrates, the nervous system is split into two parts: the central nervous system, composed of the spinal cord and brain, and the peripheral nervous system, which connects the brain to the rest of the body. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. Attempts to suture together the ends of damaged neurons in the peripheral nervous system date back to the seventh century. It was only in the late 1800s, however, that scientists began to understand how, exactly, nerves regenerate. Through his experiments on frogs, British physiologist Augustus Waller described in detail what happens to a peripheral nerve after injury. Then, in the 1900s, the influential Spanish neuroanatomist Santiago Ramón y Cajal provided insight into how nerve regeneration occurs at the cellular level. Still, there remained fierce debate about whether stitching nerves together would harm more than help. It was against the backdrop of bloody world wars of the 20th century that physicians finally made significant advances in techniques to restore damaged neurons. To treat soldiers with devastating wounds that typically involved nerve damage, doctors developed methods such as nerve grafts, in which pieces of nerves are transplanted into the gap in a broken nerve. Over time physicians learned that some peripheral nerve injuries are more conducive to repair than others. Factors such as the timing, location and size of the injury, as well as the age of the patient, can significantly impact the success of any given intervention. Crushed nerves are likelier than cut ones to be repaired, and injuries that occur closer to a nerve's target tissue have a greater chance of regaining function than those that occur farther away. Take the ulnar nerve, which stretches the entire length of the arm and controls key muscles in the lower arm and hand. A person with nerve damage near the wrist is much more likely to regain function in the arm and hand after undergoing treatment than someone who injures the same nerve near the shoulder, in which case it must regrow from the shoulder all the way to the wrist. Even today many peripheral nerve injuries remain difficult to treat, and scientists are striving to better understand the mechanisms of regeneration to facilitate healing. One notable development in recent years, according to neurologist Ahmet Höke of the Johns Hopkins University School of Medicine, is a 'nerve transfer,' in which a branch of a nearby nerve is rerouted to a damaged nerve. In cases where, for example, a nerve is damaged far from its target muscle, existing techniques may not be sufficient to enable regrowth across the long distances involved within a time frame allowing for recovery. This detour provides an alternative pathway to regain function. Susan Mackinnon, a plastic and reconstructive surgeon at Washington University in St. Louis, has largely driven the advances in nerve transfer, enabling patients to use their limbs after peripheral nerve injuries that previously would have led to a permanent loss of movement in them. For instance, Oskar Hanson, a high school baseball player, lost sensation and movement in most of his left arm after a surgery to mend a ligament injury ended up damaging the ulnar nerve in that arm. 'There was zero hope that he would be able to have use of his arm again,' says his mother, Patricia Hanson. But after Mackinnon performed a nerve transfer procedure, most of the function returned. 'She saved his life with that surgery,' Hanson says. Despite the leaps that were made in treating peripheral nerve injuries, the notion that neurons within the central nervous system—the brain and spinal cord—were incapable of regrowth persisted until the late 20th century. A pivotal moment came in the early 1980s, when Canadian neuroscientist Albert Aguayo and his colleagues demonstrated that in rats, neurons of the spinal cord and brain stem could regrow when segments of peripheral nerves were grafted into the site of injury. These findings revealed that neurons of the central nervous system can also regenerate, Höke says: 'They just needed the appropriate environment.' In succeeding years, neuroscientists worked to uncover what, exactly, that environment looked like. To do so, they searched for differences in the peripheral and central nervous systems that could explain why the former was better able to repair damaged neurons. Several key differences emerged. For example, only injuries within the central nervous system led to the formation of glial scars—masses of nonneuronal cells known as glial cells. The purpose of these scars is still debated, however. Today the search for the specific mechanisms that prevent or enable neuron regrowth—in both the body and the brain—remains an active area of investigation. In addition to uncovering the processes at play in humans, scientists have pinpointed molecules that enable nerve cell repair in other organisms, such as 'fusogens,' gluelike molecules found in nematodes. Researchers are attempting to harness fusogens to help with difficult-to-treat human nerve injuries. Modern neuroscientists have also challenged another long-standing doctrine in the field: the belief that the adult brain does not engage in neurogenesis, the creation of brand-new nerve cells. Early clues for neurogenesis in the brain emerged in the 1960s, when researchers at the Massachusetts Institute of Technology observed signs of neurons dividing in the brains of adult rats. At the time, these findings were met with skepticism, says Rusty Gage, a professor of genetics at the Salk Institute for Biological Studies in La Jolla, Calif. 'It was just too hard to believe.' Then, in the early 1980s, neuroscientist Fernando Nottebohm of the Rockefeller University discovered that in male songbirds, the size of the brain region associated with song-making changed with the seasons. Nottebohm and his colleagues went on to show that cells in the animals' brains died and regenerated with the seasons. Inspired by these findings, researchers looked for signs of adult neurogenesis in other animals. In 1998 Gage and his colleagues revealed evidence of this process occurring in the brains of adult humans—specifically within the hippocampus, a region linked with learning and memory. Although support for adult neurogenesis in humans has amassed over the years, some experts still debate its existence. In 2018 a team co-led by Arturo Alvarez-Buylla, a neuroscientist at the University of California, San Francisco, who had worked with Nottebohm on songbirds, published a study stating that the formation of new neurons was extremely rare, and likely nonexistent, in adult human brains. Still, there's a growing consensus that neurogenesis does happen later in life —and that this growth appears to be largely limited to certain parts of the brain, such as the hippocampus. This past July a team at the Karolinska Institute in Sweden reported that the molecular signatures of precursors of neurons, known as neural progenitor cells, were present in the human brain across the lifespan—from infancy into old age. Researchers are now trying to understand the purpose of these budding nerve cells and asking whether they might offer clues for treating neurodegenerative disorders such as Alzheimer's disease. Some scientists are even exploring whether, by targeting neurogenesis, they can improve the symptoms of psychiatric conditions such as post-traumatic stress disorder. Understanding that a neuron can regrow and be repaired and identifying details of that process has been a great achievement, says Massimo Hilliard, a cellular and molecular neurobiologist at the University of Queensland in Australia. The next step, he adds, will be figuring out how to control these processes: 'That's going to be key.'
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3 days ago
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A braided stream, not a family tree: How new evidence upends our understanding of how humans evolved
When you buy through links on our articles, Future and its syndication partners may earn a commission. Our species is the last living member of the human family tree. But just 40,000 years ago, Neanderthals walked the Earth, and hundreds of thousands of years before then, our ancestors overlapped with many other hominins — two-legged primate species. This raises several questions: Which other populations and species did our ancestors mate with, and when? And how did this ancient mingling shape who we are today? "Everywhere we've got hominins in the same place, we should assume there's the potential that there's a genetic interaction," Adam Van Arsdale, a biological anthropologist at Wellesley College in Massachusetts, told Live Science. In other words, different hominin species were having sex — and babies — together. This means our evolutionary family tree is tangled, with still-unknown relatives possibly hiding in the branches. Emerging DNA evidence suggests this "genetic interaction" resulted in the diversity and new combinations of traits that helped ancient humans — including our ancestors — thrive in different environments around the globe. "It's all about variation," Rebecca Ackermann, a biological anthropologist at the University of Cape Town in South Africa, told Live Science. "More variation in humans allows us to be more flexible as a species and, as a result, be more successful as a species because of all the diversity." Cutting-edge techniques may illuminate the crucial periods deeper in our evolutionary past that led to Homo sapiens evolving in Africa, or even shed light on periods before the Homo genus existed. That knowledge, in turn, could improve our understanding of exactly what makes us human. Related: Lucy's last day: What the iconic fossil reveals about our ancient ancestor's last hours A braided stream In the early 20th century, scientists thought there was a clear evolutionary line between our ancestors and us, with one species sequentially evolving into another and no contribution from "outside" populations, like the branches on a tree. But 21st-century advances in ancient DNA analysis techniques have revealed that our origins are more like a braided stream — an idea borrowed from geology, where shallow channels branch off and rejoin a stream like a network. "It becomes very hard when you think about things in more of a braided stream model to divide [populations] into discrete groups," Ackermann said. "There are not, by definition, any discrete groups; they have contributed to each other's evolution." Ackermann studies variation and hybridization — the exchange of genes between different groups — across the evolutionary history of hominins, to better understand how genetic and cultural exchange made us human. And she thinks hybridization both within and outside Africa played a significant role in our origins. Evidence of such hybridization has come out in a steady stream since the first Neanderthal genome was sequenced in 2010. That research program, which earned geneticist Svante Pääbo a Nobel Prize in 2022, revealed that H. sapiens and Neanderthals regularly had sex. It also led to the discovery of the Denisovans, a previously unknown population that ranged across Asia from about 200,000 to 30,000 years ago and that also had offspring with both Neanderthals and H. sapiens. "You have so much complexity that it makes no sense to say there was only one origin of sapiens. There can't be one universal model that explains literally every human on Earth." Sheela Athreya, Texas A&M University When species share genes with one another through hybridization, the process is known as introgression, and when those shared genes are beneficial to a population, it's known as adaptive introgression. Emerging from two decades of gene studies of humans and our extinct relatives is the understanding that we may be who we are thanks to a proclivity to pair off with anyone — including other species. Connecting with other groups — socially and sexually — was an important part of human evolution. "For us to survive and become human probably really depended on that," Van Arsdale said. Benefits of hybridization Since the first Neanderthal genome was sequenced, researchers have attempted to identify when and how often our H. sapiens ancestors mated with other species and groups. They've also investigated how Neanderthal and Denisovan genes affect us today. Many of these studies rely on large datasets of genomes from humans living today and tie them back to ancient DNA extracted from the bones of extinct humans and their relatives who lived tens of thousands of years ago. These analyses show that many genes that originated in now-extinct groups may confer advantages to us today. For instance, modern Tibetans have a unique gene variant for high-altitude living that they likely inherited from the Denisovans, while different versions of Neanderthal skin pigment genes may have helped some populations adapt to less-sunny climates while protecting others from UV radiation. There is also evidence that Neanderthal genes helped early members of our species adapt quickly to life in Europe. Given their long history in Europe prior to the arrival of H. sapiens, Neanderthals had built up a suite of genetic variations to deal with diseases unique to the area. H. sapiens encountered these novel diseases when they spread into areas where Neanderthals lived. But, by mating with Neanderthals, they also got genes that protected them from those viruses. Beyond specific traits that may confer advantages in humans today, these episodes of mating diversified the human gene pool, which may have helped our ancestors weather varied environments. The importance of modern genetic diversity can be illustrated with human leukocyte antigen (HLA) genes, which are critical to the human immune system's ability to recognize pathogens. Humans today have a dizzying array of these genes, especially in eastern Asia. This area of the world is a "hotspot" for emerging infectious diseases due to a combination of biological, ecological and social factors, so this diversity may provide advantages in an area where new diseases are frequently emerging. When genetic diversity is lost through population isolation and decline, groups may become particularly susceptible to new infections or unable to adapt to new ecological circumstances. For instance, one theory holds that Neanderthal populations declined and eventually went extinct around 40,000 years ago because they lacked genetic diversity due to inbreeding and isolation. Related: Did we kill the Neanderthals? New research may finally answer an age-old question. Discovery of "ghost populations" Some of the newest research goes deeper into evolutionary time, identifying "ghost populations" — human groups that went extinct after contributing genes to our species. Often, archaeologists have no skeletal remains from these populations, but their echoes linger in our genome, and their existence can be gleaned by modeling how genes change over time. For instance, a "mystery population" of up to 50,000 individuals that interbred with our ancestors 300,000 years ago passed along genes that created more connections between brain cells, which may have boosted our brain functioning. The population that hybridized with H. sapiens and helped boost our brains may have been a lineage of Homo erectus. This species was once thought to have disappeared after evolving into H. sapiens in Africa, but anthropologists now think H. erectus survived in parts of Asia until 115,000 years ago. In fact, our evolutionary history may include the mating of populations that had been separated for up to a million years, Van Arsdale said. These "superarchaic" populations are increasingly being discovered as we mine our own genomes and those of our close relatives, Neanderthals and Denisovans. For instance, a genetic study published in 2020 identified a superarchaic population that separated from other human ancestors about 2 million years ago but then interbred with the ancestors of Neanderthals and Denisovans around 700,000 years ago. Experts don't know exactly what genes this superarchaic ghost population shared with our ancestors or who it was, but it may have been a lineage of H. erectus. Evolutionary blank space But there's a large, unmapped region of human evolutionary history — and it's crucial for our identity as a species. The period when H. sapiens was first evolving in Africa, and the more distant period of human evolutionary history on the continent that predates the Homo genus, remains a huge knowledge gap. That's in part because DNA preserves well in caves and other stable environments in frigid areas of the world, like those found in areas of Europe and Asia, while Africa's warmer conditions usually degrade DNA. As a result, the most ancient complete human DNA sequence from Africa is just 18,000 years old. By contrast, a skeleton discovered in northern Spain produced a full mitochondrial genome from a human relative, H. heidelbergensis, who lived more than 300,000 years ago. "Maps of human ancient DNA are overwhelmingly Eurasian data," Van Arsdale said. "And the reality is that's a marginal place in our evolutionary past. So to understand what was happening in the core of Africa would be potentially transformative." This is where current DNA technology falls short. Small hominins that walked on two legs, called australopithecines, evolved around 4.4 million years ago in Africa. And between 3 million and 2 million years ago, our genus, Homo, likely evolved from them. H. sapiens evolved around 300,000 years ago in Africa and then traveled around the world. But given the scarcity of ancient DNA from Africa, it is difficult to figure out which groups were mating and hybridizing in that vast time span, or how the fossil skeletons of human relatives from the continent were related. Related: 'It makes no sense to say there was only one origin of Homo sapiens': How the evolutionary record of Asia is complicating what we know about our species A new technique called paleoproteomics could help shed light on our African origin as a species and even reveal clues about the genetic makeup of australopithecines and other related hominins. Because genes are the instructions that code for proteins, identifying ancient proteins trapped in tooth enamel and fossil skeletons can help scientists determine some of the genes that were present in populations that lived millions of years ago. Still, it's a very new technique. To date, paleoproteomic analysis has identified only a handful of incomplete protein sequences in ancient human relatives and has thus far been able to glean only a small amount of genetic information from those. But in a landmark study published this year, researchers used proteins in tooth enamel to figure out the biological sex of a 3.5 million-year-old Australopithecus africanus individual from South Africa. And in another study, also published this year, scientists used tooth enamel from a 2 million-year-old human relative, Paranthropus robustus, to identify genetic variability among four fossil skeletons — a finding that suggests they may have been from different groups, or even different species. Paleoproteomics is still pretty limited, though. In a recent study, scientists analyzed a dozen ancient proteins found in fossils of Neanderthals, Denisovans, H. sapiens and chimpanzees. They found that these proteins could help reconstruct a family tree down to the genus level, but were not useful at the species level. Still, the fact that protein data can be used to reconstruct part of the braided stream of early humans and to identify the chromosomal sex of human relatives is encouraging, and further research along these lines is needed, experts told Live Science. Some are confident new approaches could help us unpack these early interactions. "I think we're going to learn a lot more about Africa's ancient past in the next two decades than we have so far," Van Arsdale said. Ackermann is more cautious. To really understand when, where and with whom our human ancestors mated and how that made us who we are, "we need to have a whole genome" from these ancient human relatives, she said. "With proteins, you just don't get that." Sheela Athreya, a biological anthropologist at Texas A&M University, is optimistic that we can use these new techniques to tease apart our more distant evolutionary past — and that it will yield surprises. For instance, she thinks what we now call Denisovans may actually have been H. erectus. RELATED STORIES —DNA has an expiration date. But proteins are revealing secrets about our ancient ancestors we never thought possible. —28,000-year-old Neanderthal-and-human 'Lapedo child' lived tens of thousands of years after our closest relatives went extinct —Never-before-seen cousin of Lucy might have lived at the same site as the oldest known human species, new study suggests "Absolutely in my lifetime, someone will be able to get a Homo erectus genome," Athreya said, likely from colder areas of Asia. "I'm excited. I think it'll look Denisovan." Either way, it's clear that a whole lot of mixing made us human. The Homo lineage may have first evolved in Africa, Athreya said. "But once it left Africa, you have so much complexity that it makes no sense to say there was only one origin of sapiens. There can't be one universal model that explains literally every human on Earth."
