Brain Circuit Stores a Memory of Stress: Researchers at Mount Sinai have identified a previously overlooked brain circuit that helps prior adversity shape responses to future threats. In mice, the anterior hypothalamic nucleus, or AHN, became more sensitive after stressful experiences and coordinated more strongly with regions including the amygdala, hippocampus and prefrontal cortex. Increasing AHN activity intensified defensive responses, while suppressing it reduced them. Most strikingly, silencing the pathway from the amygdala to the AHN prevented earlier stress from amplifying reactions to later threats. Published in Nature, the study suggests the brain may retain a functional “memory” of stress that adjusts how strongly future danger is perceived. Researchers caution that the work was conducted in mice, but say the circuit could eventually inform research into PTSD, anxiety and depression. (Newswise)
Magnetic Headset Improves Long-COVID Cognition: A small randomized, triple-blind trial suggests low-amplitude magnetic stimulation may improve cognitive problems associated with long COVID. Thirty participants with objectively measured cognitive impairment were assigned to active or sham treatment using a head-worn device that delivered nonthermal radio-frequency magnetic fields for 15 minutes twice weekly over four weeks. Participants receiving active therapy improved on measures of working memory, verbal learning, processing speed and emotional well-being compared with the sham group. Some improvements continued four weeks after treatment ended. Published in Brain Communications, the trial was designed primarily to assess feasibility and safety rather than prove effectiveness. Researchers emphasize that the therapy remains investigational and requires replication in larger trials, but the results provide early evidence for a potential non-drug approach to persistent neurological symptoms. (Mount Sinai Health System)
Lung Cancer Escapes KRAS Drugs Two Ways: Lung tumors can evade KRAS-targeting drugs through at least two fundamentally different routes, according to MIT researchers. About one-quarter of lung adenocarcinomas carry KRAS mutations, and targeted inhibitors can initially shrink some tumors before resistance develops. Scientists found that certain resistant tumors simply increase KRAS activity enough to overwhelm treatment. Others undergo a more dramatic identity change, transforming from adenocarcinoma into squamous cell carcinoma. After this shift, the cancer cells no longer depend on KRAS and instead activate alternative growth pathways. The findings, published in Nature Genetics, suggest that resistance should not be treated as a single biological problem. Identifying which escape mechanism a tumor is using could eventually determine the best follow-up therapy and may reveal new targets for preventing or overcoming resistance. (MIT News)
Sugar May Worsen Antibiotic Damage to Gut Microbes: Eating large amounts of simple sugar while taking antibiotics may intensify disruption of the gut microbiome. Researchers tracked 9,419 meals consumed by 173 people undergoing stem-cell transplantation and compared diet with changes in intestinal bacteria during antibiotic treatment. Greater consumption of sweets and sugars predicted lower microbial diversity and stronger expansion of Enterococcus, a bacterial genus that can cause dangerous infections in vulnerable patients. Experiments in mice supported the association: adding sucrose to the diet increased and prolonged antibiotic-driven Enterococcus expansion. Published in Nature, the study suggests diet can influence how severely antibiotics disturb intestinal ecosystems. Researchers caution that the findings do not yet justify universal dietary recommendations for everyone taking antibiotics, but they raise the possibility that limiting simple sugars could eventually become one strategy for protecting the microbiome during treatment. (Medical Xpress)
Roman Telescope Takes First Coronagraph Image: NASA’s Nancy Grace Roman Space Telescope has completed important commissioning milestones, including its first observations with the Coronagraph Instrument. Roman’s fine-guidance system successfully held the observatory steady to better than one hundred-thousandth of a degree during extended tests, precision essential for its planned deep surveys and exoplanet observations. On September 22, the coronagraph captured its first focused image of a faint star in the Large Magellanic Cloud, followed by a second observation containing multiple stars. The instrument will eventually demonstrate advanced technology for suppressing overwhelming starlight so astronomers can directly study much fainter planets and circumstellar disks. NASA emphasizes that these are engineering tests rather than science observations, but the successful imaging confirms that light is moving through the coronagraph correctly as Roman continues commissioning. (NASA Science)
Butterfly Wings Create Illusions That Foil Predators: Butterflies may escape attacking birds partly by turning their patterned wings into moving optical illusions. Researchers from the University of Exeter and University of Essex found that stripes and spots interact with rapidly deforming wings to confuse visual systems trying to calculate a butterfly’s speed and direction. The effect resembles the classic barber-pole illusion, in which moving stripes appear to travel in a misleading direction. Using high-speed footage exceeding 1,000 frames per second, researchers analyzed butterflies taking flight and examined patterns across roughly 400 European species. Volunteers also attempted to capture virtual butterflies on touchscreens. The results suggest that wing patterns can misdirect a predator during the final milliseconds of an attack, causing it to miss entirely or strike expendable portions of the wing rather than the body. (Discover Wildlife)
Insect Declines Threaten Much More Than Food Webs: A sweeping review argues that conserving insects is essential not simply because vertebrates eat them, but because insects provide animals with medicine, shelter, sanitation and protection. Nearly three-quarters of terrestrial and freshwater vertebrates consume invertebrates, yet researchers documented numerous less obvious relationships. Chimpanzees have applied insects to wounds, more than 200 bird species use ants in feather maintenance, bats roost inside termite mounds and dung beetles remove waste that can harbor parasites. Some frogs obtain defensive toxins from insects, while sloths depend on moths that help fertilize algae growing in their fur. Researchers warn that widespread insect declines could therefore trigger cascading ecological effects extending far beyond reduced prey availability. Better understanding these overlooked relationships, they argue, should become an important component of biodiversity conservation planning. (The Guardian)
Brazil May Harbor Several of Earth’s Loudest Birds: Some Brazilian birds may rank among the loudest animals on Earth, according to new research examining the evolution of extreme avian vocalizations. University of Massachusetts Amherst biologists compared species including the white bellbird, previously measured producing calls reaching roughly 125 decibels—louder at close range than a jackhammer. The researchers found multiple extraordinarily loud Brazilian species, suggesting extreme sound production may have evolved repeatedly rather than appearing as an isolated peculiarity. Why natural selection favors such ear-splitting calls remains uncertain, although sexual selection appears to be an important possibility. Male white bellbirds famously direct explosive calls toward nearby females during courtship. Understanding how these birds physically generate and tolerate such intense sound could provide broader insights into vocal evolution, animal communication and the physiological limits of acoustic signaling. (WBUR)
Biscayne Bay Emerges as Critical Shark Nursery: A global mapping effort has identified Miami’s heavily urbanized Biscayne Bay as an unexpectedly important refuge for sharks and rays. Scientists working with the International Union for Conservation of Nature documented the bay as habitat for at least 13 shark and ray species, eight of which are listed as threatened. Pregnant and juvenile bull, tiger, blacktip and sandbar sharks use its shallow seagrass-rich waters, while critically endangered great hammerheads appear to have their only formally documented nursery on the U.S. East Coast there. Researchers used acoustic tracking, drones, blood samples, genetic analysis and reproductive assessments gathered over nearly a decade. The designation imposes no new fishing or development restrictions, but scientists hope recognition of the bay’s importance will strengthen habitat protection as marina construction and coastal development increase. (WLRN)
Recreation and Roads Reduce Wolverine Populations: Outdoor recreation may reduce wolverine numbers across entire landscapes, rather than simply causing individual animals to temporarily avoid people. Researchers studying 81,800 square kilometers of western Alberta and eastern British Columbia estimated fewer than 300 wolverines occupy the region. Their analysis found both road density and recreational activity—including backcountry skiing, hiking, heliskiing and cross-country skiing—were associated with lower population density. Researchers estimated wolverine abundance might be roughly 30 percent higher without current levels of roads and recreation. Females appeared particularly affected by roads, potentially creating an added conservation concern because wolverines reproduce slowly, generally producing only one to three young every few years. Published in Biological Conservation, the study recommends preserving roadless areas, protecting high-quality low-disturbance habitat and limiting recreation near important reproductive areas. (EurekAlert!)
Hundreds of Endangered Frogs Return to California Mountains: Conservationists have released more than 650 endangered southern mountain yellow-legged frogs into streams in California’s San Gabriel Mountains as part of a decades-long effort to rebuild the species. Once so abundant that biologists reportedly struggled to avoid stepping on them, the frogs have suffered catastrophic declines since the 1950s. Introduced trout, habitat loss, climate change and especially the chytrid fungus Batrachochytrium dendrobatidis have contributed to their disappearance. A 2023 survey counted fewer than 200 frogs in the southern population, representing an estimated 98 percent decline. Captive-breeding programs now involve multiple zoos, aquariums and government agencies. Researchers are also testing antifungal treatments, immune priming and genetic strategies. Reintroductions remain critical for spreading surviving populations across multiple habitats and reducing the risk that a single fire, drought or disease outbreak could eliminate them. (Conservation news)
Two Strange Sea Spiders Discovered in Salish Sea: Scientists have described two previously unknown sea spider species from the Salish Sea, the first new species formally documented there in nearly a century. University of British Columbia researchers combined genetic analysis with detailed microscopy after collecting specimens around Vancouver Island and nearby waters. Callipallene pilosuspedes has long curved leg spines, red eyes and unusually flexible appendages that it apparently uses like combs to groom itself. The second species, Tanystylum kiixin, possesses less effective grooming structures and is often covered with debris and tiny parasites. Sea spiders belong to an ancient marine arthropod lineage roughly 500 million years old and possess unusual biology: they breathe through their skin, males carry developing eggs, and some species feed by sucking fluids from other animals. Researchers suspect many additional undocumented species remain in the region. (ScienceDaily)
Massive Genome Study Rewrites Bat Evolution: The largest genomic investigation of bats yet conducted suggests the flying mammals originated in Europe roughly 65 million years ago before spreading through Africa and eventually across much of the planet. More than 130 researchers analyzed genomes from 103 species representing all 21 living bat families, alongside anatomical information from 65 species and 44 fossils. The resulting evolutionary tree resolves relationships that have remained uncertain for decades and challenges previous ideas about where bats first evolved. It also complicates the debate over whether powered flight appeared before echolocation: the expanded dataset suggests both traits emerged very early in bat evolution. The research, part of the Bat1K genome initiative, could also illuminate the genetics behind bats’ extraordinary longevity, disease resistance and sensory biology while improving conservation strategies for threatened species. (Smithsonian Magazine)
Butterfly Colors Extend Into an Invisible World: Research on Delias butterflies suggests their famous warning coloration includes an entire layer invisible to human eyes. Scientists studying the extraordinarily diverse genus—containing roughly 250 species—found ultraviolet-reflecting wing patches occurring alongside familiar red, yellow and black warning patterns. Interestingly, the UV structures may arise through a relatively simple mechanism: scales reflecting ultraviolet wavelengths appear to remain essentially unpigmented rather than producing a specialized UV pigment. Because many birds and insects can perceive ultraviolet light, these patterns could dramatically alter how predators, mates and rival butterflies experience the animals’ coloration. The findings highlight a persistent limitation in studying visual ecology from a human perspective: organisms frequently communicate using wavelengths people cannot see. Researchers say incorporating ultraviolet imaging could therefore reveal previously overlooked patterns in warning coloration, mimicry, mate selection and butterfly evolution. (Entomology Today)