2-24-21 Walker Swamp: The mission to restore an Australian wetland
In the shadow of Australia's Grampians National Park lies Walker Swamp, a once-thriving wetland that was artificially drained and farmed for over a century. But it is now welcoming new life once more, after a huge restoration project. Its revival is one "message of hope" amid so much grim environmental news, ecologists tell the BBC.
2-24-21 Rescued orangutans returned to the wild
An Indonesian rehabilitation in Borneo has released 10 orangutans into the wild. The endangered animals had previously been in captivity before their rescue. In total five males, two females and a mother with two babies were released.
2-24-21 Most pheasants sold for food 'contain lead shot'
Almost all pheasants sold for food in the UK contain toxic lead shot, scientists have found. The discovery comes one year into a five-year transition to non-toxic shotgun ammunition - a move backed by nine UK shooting organisations. Of 180 birds examined by the scientists, 179 were shot with lead. One shooting group said finding humane and effective alternatives to lead would take time. The team, consisting of scientists and conservationists based across England and Scotland, bought wild-shot common pheasants that were sold by game dealers, butchers and supermarkets around the UK. With labs closed in lockdown, the scientists carried out the pheasant dissections in their own kitchens. "We took out the shot and sent it off for analysis and 99% of the ammunition we extracted was lead," said Prof Debbie Pain, from Cambridge University. "So really that hasn't declined at all since the shooting organisations signed up to the voluntary ban." That voluntary ban was a declaration in February 2020 by shooting and countryside organisations, which all committed to phasing out lead shot and transitioning "completely" to non-toxic alternatives. Those alternatives are already widely available and include steel, bismuth and tungsten. That commitment, the scientists conclude, has not yet had any detectable impact. Lead is toxic even at very low concentrations, as Prof Rhys Green from Cambridge University explained. "Over time, it has been banned from a progressively lengthening list of products, including plumbing, paints on things like children's toys and as an additive to petrol. And the maximum allowable concentration of lead in many foods has also been limited by an EU directive, which still applies in the UK," he said. "But game meat products are not included on that list of foods, for reasons that are unclear. Currently, the amount of lead in game meat sold for human consumption is not regulated by law." Lead shot also builds up in the environment.
2-24-21 Whales and dolphins can resist cancer and their DNA reveals why
Whales, dolphins and porpoises are much better at fighting cancer than we are, and now we might be closer to understanding why cetaceans can do this. Generally speaking, cetaceans are the most long-lived mammals, with some whale species reaching their 200th birthday. Why this should be possible is a mystery given that their size means their bodies contain far more cells than the human body does. “If you have more cells, that means that the risk that one of those cells… becomes cancerous increases,” says Daniela Tejada-Martinez at the Austral University of Chile. “So, if you are big or live longer, you have thousands and millions of cells that could become harmful.” Instead, cetaceans have much lower rates of cancer than most other mammals, including humans. This situation is known as Peto’s paradox. “There’s a joke that whales should be born with cancer and not even able to exist because they’re just too big,” says Vincent Lynch at the University at Buffalo, New York. He says there is a “super trivial” explanation for how whales can exist. “They just evolved better cancer protection mechanisms,” he says. But we still need to learn more about why and how they did this. Now, Tejada-Martinez and her colleagues have studied the evolution of 1077 tumour suppressor genes (TSGs). In all, they compared the evolution of the genes in 15 mammalian species, including seven cetacean species. Genes regulating DNA damage, tumour spread and the immune system were positively selected among the cetaceans. The team also found that cetaceans gained and lost TSGs at a rate 2.4 times higher than in other mammals. “It’s not like we’re gonna be taking whale genes and putting them into humans and making humans cancer resistant,” says Lynch. “But if you can find the genes that play a role in tumour suppression in other animals, and if you could figure out what they’re doing, maybe you can make a drug that mimics that for human treatment.”
2-24-21 Moth species becomes more sexually active when bathed in red light
An Asian-Australian moth becomes more sexually active under red light than under another colour of light or in the dark. Dim red light appears to stimulate chemical changes in the antennae of male yellow peach moths (Conogethes punctiferalis), making them more sensitive to the smells emitted by nearby females. This increases their copulation rates, says Wei Xiao at Southwest University in Chongqing, China. Xiao and his colleagues made the accidental discovery while studying the general behaviour of the moths, which invade orchards and spice farms across Asia and Australia. To mimic natural light conditions in their laboratory, the scientists kept the lights on for 15 hours and turned them off for 9 hours per day. When they needed to work with the moths during the hours of darkness, they turned on red lights because scientists generally assume that insects can’t see red and react negligibly to it, says Xiao. However, his team realised that every time the red lights were on, the moths responded by laying more eggs. So the researchers decided to test the effects of red light on mating. They set up four cages, three of which were dimly lit by either red, white or blue light. The last was in complete darkness. Then they placed 30 male and 30 female moths in each cage. They found that the moths in the cage exposed to red light mated significantly more frequently and laid more eggs than the moths in the other cages, says Xiao. To understand why, the scientists analysed the antennae of male moths that they had raised in conditions with 15 hours of normal light and 9 hours of dim red light. They found that these moths had more odorant binding proteins (OBPs) in the smell receptors of antenna neurons, apparently making them hypersensitive to female sex pheromone odours.
2-23-21 Extinction: Freshwater fish in 'catastrophic' decline
A report has warned of a "catastrophic" decline in freshwater fish, with nearly a third threatened by extinction. Conservation groups said 80 species were known to have gone extinct, 16 in the last year alone. Millions of people rely on freshwater fish for food and as a source of income through angling and the pet trade. But numbers have plummeted due to pressures including pollution, unsustainable fishing, and the damming and draining of rivers and wetlands. The report said populations of migratory fish have fallen by three-quarters in the last 50 years. Over the same time period, populations of larger species, known as "megafish", have crashed by 94%. The report, The World's Forgotten Fishes, is by 16 conservation groups, including WWF, the London Zoological Society (ZSL), Global Wildlife Conservation and The Nature Conservancy. In UK waters, the sturgeon and the burbot have vanished, salmon are disappearing and the European eel remains critically endangered. According to the WWF, much of the decline is driven by the poor state of rivers, mostly as a result of pollution, dams and sewage. It has called on the government to restore freshwater habitats to good health through proper enforcement of existing laws, strengthening protections in the Environment Bill and championing a strong set of global targets for the recovery of nature. Dave Tickner, from WWF, said freshwater habitats are some of the most vibrant on earth, but - as this report shows - they are in catastrophic decline around the world. "Nature is in freefall and the UK is no exception: wildlife struggles to survive, let alone thrive, in our polluted waters," said the organisation's chief adviser on freshwater. "If we are to take this government's environmental promises seriously, it must get its act together, clean up our rivers and restore our freshwater habitats to good health. "
2-23-21 A mountain lizard in Peru broke the reptilian altitude record
A Liolaemus lizard was photographed at 5,400 meters above sea level. High in the Peruvian Andes, a lizard has claimed the title of world’s highest altitude reptile. The lizard was spotted as high as 5,400 meters in elevation, exposed to frigid temperatures, intense ultraviolet radiation and low oxygen, researchers report February 15 in Herpetozoa. In October 2020, zoologist José Cerdeña and colleagues ascended Peru’s Chachani volcano, which rises 6,057 meters above sea level. The team was looking for Liolaemus lizards, also known as tree iguanas, and found them as the researchers climbed above 5,000 meters. “We observed something moving between the rocks,” says Cerdeña, of the National University of Saint Augustine in Arequipa, Peru. “At first we thought they were mice.” After getting a closer look, he and his team saw that the darting animals were actually lizards, tentatively identified as Liolaemus tacnae. The species is known to survive at high altitude areas in Peru, and at least one population near Chachani was previously spotted some 4,000 meters above sea level. Survival in such forbidding conditions is hard enough for mammals (SN: 7/29/20). But cold-blooded reptiles face additional temperature regulation obstacles, so records of reptiles this high are rare. Until now, the highest living reptile was a cold-hardy species of toad-headed agama lizard (Phrynocephalus erythrurus) living on the Tibetan Plateau at 5,300 meters. The Andean lizard breaks the old record by 100 meters. It’s somewhat fitting that the record goes to a species of Liolaemus lizard. The genus is exceptionally diverse, with more than 270 species adapted to a wide range of habitats all over South America. Climate change could have facilitated Liolaemus’ status as a record holder, Cerdeña notes, as colder conditions have retreated up mountain peaks in the face of warming. “It is possible that this lizard species began to colonize this altitude recently,” he says. The research group’s next steps are to verify the identification of the lizard with physical and genetic analysis, Cerdeña says. He also wants to know more about the reptile’s physiology, which may hold secrets to its high-altitude lifestyle.
2-22-21 Watch a slug use a thin thread of slime as a slide to reach the ground
Slugs are generally content to lazily munch garden greens, but one of these lethargic molluscs has recently been spotted taking to the air, descending vertically down a string of slime like a spider dangling from a line of silk. The discovery represents a new type of locomotion never seen before in slugs. John Gould, an ecologist at the University of Newcastle in Australia, was conducting fieldwork on frogs on Kooragang Island, New South Wales, when he found a striped field slug (Lehmannia nyctelia) hovering about a metre above the ground. “At first, I thought I had stumbled upon a spider that was making its way to the ground on a silk thread,” says Gould. The slug was suspended on a taut slime thread stretched from the top of a fence to some gravel below. Gould watched as the slug glided down about half the thread’s length in only a couple of minutes – fast, for a slug. “When John first told me about it, I just didn’t believe it,” says Jose Valdez, a conservation biologist at the German Centre for Integrative Biodiversity Research in Leipzig and co-author of the new study. After seeing Gould’s video footage and delving into the scientific literature, it became clear to Valdez that this was a unique observation. Leopard slugs (Limax maximus) will mate while hanging by a rope of thick mucus, says Valdez, but this was “a single slug with a relatively thin mucus [thread], descending towards the ground before it went on its way”. These mucus slides may be useful for quickly escaping predators like ants or lizards. “It is possible that descending on a single mucus thread saves both mucus and energy, as it’s such a thin line of material that needs to be produced,” says Gould. A single observation like this isn’t enough to make generalised claims about the behaviour of an entire population of slugs, says Jann Vendetti at the Natural History Museum of Los Angeles County. “But it could inspire more thought about that behaviour or trait and jumpstart research and experimentation,” she says.
2-21-21 Kangaroo Island dunnart: Saving a bushfire-ravaged marsupial
The Kangaroo Island dunnart was already critically endangered when its habitat was ravaged by Australia's bushfires last year. Now ecologists are desperate to protect the "cryptic and mysterious" marsupial.
2-19-21 Texas weather: Thousands of cold-stunned turtles rescued
Around 4,700 turtles have been saved from the deadly US winter storm by a rescue centre in Texas. The freezing conditions have left the reptiles cold-stunned and in danger of drowning. The "Herculean" task has been made even more difficult because the centre, Sea Turtle Inc in South Padre Island, is dealing with no electricity.
2-18-21 Dogs prove they are aware of their own bodies when playing fetch
Dogs seem to be conscious of their bodies and understand that their own actions have consequences. Research has previously shown that dogs can pick up on human emotions and can use deception, but it has been unclear whether or not they show self-awareness. “We need to take into account the ecology and evolution of the species,” says Rita Lenkei at Eötvös Loránd University Budapest, Hungary. “As they evolved in complex human societies, dogs should possess one of the basic self-awareness abilities,” she says. So Lenkei and her colleagues performed a test for body awareness in which an individual’s body became an obstacle to achieving a goal. In a test involving 32 dogs, the researchers instructed each animal to retrieve a toy. In some cases, the toy was attached to a mat that the dog was standing on, meaning the animal had to move off the mat in order to bring the toy to the instructor. In other cases, the toy was secured to the ground, making it impossible to retrieve even if the dog left the mat. For the trials in which the toy was attached to the mat, the team found that about 80 per cent of dogs left the mat when attempting to complete the task – the figure dropped to 50 per cent for the trials in which the toy was attached to the ground. What’s more, dogs that left the mat were more likely to do so with the toy in their mouth if the toy was attached to the mat rather than to the floor. Lenkei says these findings suggest that dogs understand their bodies can get in the way when it comes to completing tasks and know to move accordingly, pointing towards a sense of body awareness. Juliane Bräuer, who runs the dog labs at the Max Planck Institute for the Science of Human History, Germany, says these results aren’t surprising, but lay the groundwork for future self-awareness studies. “We know dog strengths lie in social cognition and communication, so it’s interesting to show they actually know something about their physical environment,” says Bräuer.
2-17-21 Ten conservation success stories when species came back from the brink
The blue whale, the mountain gorilla and the European bison are among the animals that have avoided extinction, showing what works to preserve the world’s wildlife. LOOK at how we missed all 20 of the past decade’s biodiversity targets, or shocking graphs of animals threatened with extinction, and it is easy to be disheartened about the fate of the natural world. “There’s lots of doom and gloom stories around about biodiversity,” says Stuart Butchart at the conservation body BirdLife International. “It would be easy to feel conservation was a pointless exercise and there’s nothing we can do to slow the juggernaut down.” Butchart’s work suggests that isn’t the full picture, however. He was part of a team that recently estimated that conservation initiatives had prevented up to 32 bird and 16 mammal extinctions since 1993. Given that 10 bird and five mammal species are known to have gone extinct in that time, the researchers concluded that extinction rates would have been up to four times higher without action. “I think that’s a positive message. It’s not all bad news, always,” says Friederike Bolam at Newcastle University, UK, the study’s lead author. Many of the most successful conservation efforts involve big “charismatic” species, such as the giant panda, that readily attract attention and funding. But Bolam and Butchart’s team identified a number of recurring and widely applicable themes in successful conservation work: removal of invasive species, management of hunting and protection of important habitats. “Broadly speaking, we have the tools, we just need much greater resource and political will,” says Butchart. Even so, targeted actions won’t turn the tide alone. Stemming biodiversity loss will also require more fundamental changes to how we value nature – and whether those will be forthcoming is the trillion-dollar question. For now, here are 10 conservation success stories from around the globe that give some idea of what works.
2-17-21 Some frogs stop being able to jump if they become dehydrated
When some frogs lose too much water they also lose their ability to jump – more evidence of the problems they face with climate change. Dan Greenberg at Simon Fraser University in Burnaby, Canada, and his colleague Wendy Palen experimented with three species: the coastal tailed frog (Ascaphus truei), which lives near cold mountain streams, the desert-adapted great basin spadefoot toad (Spea intermontana) and the Pacific tree frog (Pseudacris regilla), which can adjust to various habitats. The researchers measured the animals’ jumping distances after placing them in environmental chambers to control their body temperature and dehydration levels. They found that the more dehydrated the amphibians were, the shorter the distance they could cover in one jump. Once dehydration had led the frogs to lose 30 per cent of their body weight – 45 per cent for the toad – they stopped jumping entirely. The pair also found that a combination of dehydration and temperature increases – ranging from 15 to 30°C, depending on the species – led to even shorter jumps. All the frogs and toads rapidly recovered their jumping ability after being placed back in water, says Greenberg. The researchers think they may know why dehydration has this effect. Dehydration disrupts the ion exchanges in the cells as well as the supply of nutrients and removal of waste within the muscles, affecting their function, says Greenberg. It can also make the blood more viscous, challenging the heart’s pumping efficiency, and making physical movement more difficult. The pair think the effect might apply to other animals that have less control over body temperature such such as insects, arthropods and reptiles. The findings highlight the importance of considering water loss, in addition to increased heat, when estimating the impact of global warming on frogs and other animals, says Greenberg.
2-17-21 A tiny spider can spin different types of web for land, air and water
An island spider decides which of its three kinds of webs to make depending on location and perhaps individual preferences. Spiders usually make only one kind of web, but the Wendilgarda galapagensis spider – which lives exclusively on Cocos Island, about 550 kilometres off the western coast of Central America – can make three different webs. High above ground it makes “aerial” webs attached to nearby stems and leaves. Nearer to the ground it makes “land” webs with long horizontal strands secured between branches and with a series of vertical strands anchored to the ground. Finally, over pools it makes “water” webs that are a bit like the land webs, but with the vertical strands attached to the water surface itself. Darko Cotoras at the California Academy of Sciences in San Francisco wondered whether this flexibility in web construction indicates the spider is undergoing speciation, splitting into three distinct species, each with unique behaviours and exploiting a different food source. So with his colleagues he ran genomic analyses on 142 of the spiders. To the team’s surprise, the results revealed that all of the spiders belonged to the same species, says Cotoras. This means they haven’t genetically diversified since arriving on the newly formed volcanic island perhaps as long as two million years ago, when their ancestors were probably carried in by air currents. The researchers then marked the 2-millimetre-long spiders with drops of fingernail polish and moved them to different locations on the island to track their behaviour. For example, they took water-web-making spiders away from water sources and placed them in high bushes nearby. Again, the researchers were surprised to see that the spiders often built a new web with the architecture suited to the new location.
2-17-21 Knifefish use electric fields to develop a complex social hierarchy
The rivers of the tropical Americas hum and crackle with electric fields generated by knifefish. The fish use electric discharges to search their murky surroundings for food and to communicate with mates. But new research suggests these electric signals may also be used to develop and maintain a sophisticated social order. Brown ghost knifefish (Apteronotus leptorhynchus) are related to electric eels, but rather than emitting powerful jolts, the fish continuously produce weak electric fields. Still, when Till Raab, a neuroethologist at the University of Tübingen in Germany, and his colleagues went to the fish’s natural habitat in Colombia in 2016 to study their social behaviour, they came away with “more questions than answers”, says Raab. In just a 9-square-metre area, Raab and his colleagues recorded 30 fish communicating with each other electrically. So many fish in one spot inevitably means competition for food, shelter and mates – and the knifefish exist in these high densities across South America. The researchers knew “there must be some kind of hierarchy to avoid constant, repetitive fighting”, says Raab, so they brought some of the fish into the lab. They paired 21 knifefish in 37 different combinations in tanks each containing a shelter made of PVC pipe. The fish competed for access to the shelters, and the researchers recorded their behaviours using infrared cameras and their electric discharges using electrodes in the tank. The team found that fish denied access to the shelter would commonly target their competitor with electric “rises”: gradual increases in discharge frequency followed by a rapid fall to normal. Initially, Raab thought these might be submissive gestures, but what he found “was way more complex”.
2-17-21 A rare bird sighting doesn’t lead to seeing more kinds of rare birds
The so-called Patagonia Picnic Table Effect is a myth, an analysis of bird sightings suggests. It was a cold, overcast Saturday morning in Salem, Ore., when Jesse Laney set out to catch a glimpse of a painted bunting. He’d heard earlier that week through a birding WhatsApp group that this vibrant, rainbow-colored bird was in the area. Painted buntings (Passerina ciris) are common in places like Texas and the northern parts of Mexico, but a rarity in Oregon. Laney and his sons raced to the site and began searching — but the bird eluded them. He wasn’t too disappointed, though. Just the chance of seeing a rare bird “scratches the ever-present itch of participating in a small bit of discovery,” says Laney, an ecologist at Oregon State University in Corvallis. That itch has now inspired research debunking a popular myth among birders: That a rare bird sighting leads to more sightings of other rare bird species because birders flock to an area to find the initial bird. This phenomenon is called the Patagonia Picnic Table Effect. Its origin story dates back to sometime in the 1960s or ‘70s. Though details are a bit unclear, birders saw a rare black-capped gnatcatcher, or a pair of rose-throated becards, in Patagonia, a town near the Arizona-Mexico border. Word got around and birders descended on the town, which led to sightings of other rare birds, including a five-striped sparrow and a yellow grosbeak, according to some accounts. To determine if such discovery bonanzas are one-off events or a common occurrence, Laney and his colleagues analyzed data from 2008 to 2017 from the online database eBird. Avid birders typically upload their checklists — that is, birds they have spotted on an outing — to the site. The team identified 273 so-called mega-rarities mostly in the continental United States; these are the hardest-to-find birds, either because there are so few of them or because they rarely show up in some geographical locations. The researchers then evaluated rare bird discovery rates before and after crowds raced to where those ultra-uncommon birds were spotted.
2-16-21 Modified genes can distort wild cotton’s interactions with insects
In Mexico, acquired herbicide resistance and insecticide genes can disrupt cotton’s ecosystem. Cotton plants native to Mexico’s Yucatan Peninsula may all look the same — unkempt and untamed bushes with flowers that shift from pale yellow to violet as pollinators visit them. But genes that have escaped from genetically modified cotton crops have made some of these native plants fundamentally different, changing their biology and the way they interact with insects. One type of escaped gene makes wild cotton exude less nectar. With no means to attract defensive ants that protect it from plant eaters, the cotton is devoured. Another escaped gene makes the wild cotton produce excess nectar, enticing a lot of ants that might keep other insects, including pollinators, at bay, researchers report on January 21 in Scientific Reports. “These are profoundly interesting effects,” says Norman Ellstrand, an evolutionary biologist at the University of California, Riverside. “It’s the first case that really suggests that a whole ecosystem can be disrupted” after transgenes enter a wild population. The results challenge one long-held view that when genes from genetically modified crops escape into the wild, they have only a neutral effect on wild plants or pass on their benefits to weeds, says Alicia Mastretta Yanes, a plant molecular ecologist at the National Commission for the Knowledge and Use of Biodiversity in Mexico City. The findings confirm that unexpected outcomes of this genetic transfer, some of which “were never imagined, or at least were not assumed as possible,” do happen sometimes, she says. Scientists have previously tried to explain what happens after DNA from genetically modified crops ends up in their wild relatives (SN: 1/29/16). But the majority of studies have been done under carefully controlled conditions, and very few have tested the consequences, if any, of these gene transfers on natural ecosystems.
2-15-21 Chimpanzees seem to 'speak' in sentences of three or more calls
Chimpanzees regularly string many different calls together into sequences, which are often three calls long and sometimes even longer. The finding suggests that the apes are more creative with their vocalisations than previously thought. It also opens up the possibility of chimps combining calls to create new meanings, a skill thought to be unique to humans – although far more evidence would be required to show this. Chimpanzees (Pan troglodytes) are our closest living relatives. They live in groups of a few dozen individuals and communicate with a mix of gestures and calls, including grunts, barks and screams. This is a far cry from the complex language that humans use. In particular, humans can combine words to create meanings not present in the individual words, such as “this duck quacks in the ultrasonic”. By contrast, it isn’t clear that chimpanzees’ calls convey subtle or complex meanings. They may simply be a way of achieving goals, like warning friends about snakes by startling them. Crucially, there also seem to be limits to the ability of animals, including chimps, to combine calls in sequences. Some songbirds obey rules about the order that pairs of sounds should take, but nothing beyond that. This implies that they can’t convey anything subtler than things like “snake alert”. Cédric Girard-Buttoz at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and his colleagues recorded the calls of 46 adult chimpanzees in Taï National Park in Côte d’Ivoire. They obtained 900 hours of data, including 4826 utterances. While 3232 of these were single calls, 817 were paired calls and 458 were triplets. There were also longer sequences, but these were rare: there were only two instances of a sequence of 10 calls, for example. The team found clear patterns in the call sequences. In paired calls, grunts and hoos tended to come first, while panted barks and other calls tended to come second.
2-15-21 High-altitude birds evolved thicker 'jackets'
A study of 250 species of Himalayan songbirds has revealed how their feathers evolved for higher altitudes. The birds in colder, more elevated environments had feathers with more fluffy down - providing them with thicker "jackets". The insight reveals how feathers provide the tiniest birds with such efficient protection from extreme cold. It also provides clues about which species are most at risk from climate change, the scientists say. The study, in the journal Ecography, was inspired by a tiny bird lead researcher Dr Sahas Barve saw during an icy day of fieldwork in the Himalayas, in 2014. "It was -10C," said the researcher from the Smithsonian National Museum of Natural History, in Washington DC. "And there was this little bird, a goldcrest, which weighs about the same as a teaspoon of sugar. "It was just zipping around catching bugs." Dr Barve's fingers went numb as he tried to take notes. But he remembers being "blown away by the little goldcrest". "To survive, this bird has to keep its heart at about 40C," he said. "So it has to maintain a difference of 50C in that little space. "I was like, 'OK, I really need to understand how feathers work.'" Fortunately, Dr Barve's home institution has one of the largest bird collections in the world. Examining the feathers of nearly 2,000 individual birds, in microscopic detail, he noticed a pattern linked their structure to their habitat. Each feather has an outer part and a hidden downy portion. And Dr Barve's measurements revealed those living at higher elevations had more of the lower fluffy down. "They had fluffier jackets," he said. Smaller birds, which lose heat faster, also tend to have longer feathers in proportion to their body size, revealing the little goldcrest's secret. Dr Carla Dove, who runs the museum's Feather Identification Lab and contributed to the study, said she was excited to use the Smithsonian's collections in a new way. "Having them all in one place, as opposed to having to go to the Himalayas and study these birds in the wild, obviously makes a big difference," she said.
2-14-21 Where are Cape Town's great white sharks?
For years, one of South Africa’s great tourist attractions has been the opportunity to see, up close, one of the world’s most fearsome predators - the great white shark. But barely a single one has been spotted off the coast of Cape Town for two years now – where there used to be hundreds. What’s going on?
2-12-21 Meatier meals and more playtime might reduce cats’ toll on wildlife
Simple steps to keep felines happy can also keep more wild birds and mammals alive. Surprisingly simple measures might keep domestic cats from killing a lot of wildlife. Estimates vary, but it’s likely that billions of birds and mammals succumb each year to our outdoor-ranging feline friends (SN: 1/29/13). Calls to keep cats indoors are often contentious among cat owners, and cats can sometimes reject colorful collars or loud bells designed to make them more noticeable. But a meat-rich diet or a few minutes of hunting-like play each day can significantly reduce the amount of wildlife they bring home, researchers report February 11 in Current Biology. Interventions that reduce cat predation and have buy-in from cat owners “are so important because we’re just decimating bird populations,” says Susan Willson, an ecologist at St. Lawrence University in Canton, N.Y., who wasn’t involved in the study. While preliminary, she says this study shows that “simply feeding your cat a high-meat diet might actually work.” Most attempts to curb cats’ impact on wildlife have focused on restricting cat behavior and their ability to hunt. But Robbie McDonald, an ecologist at the University of Exeter in Cornwall, England, and his colleagues investigated the root of the problem: the urge to go out hunting in the first place. “We wanted to find out why well-fed cats might still kill wildlife,” he says. The team reasoned this urge might stem from natural instincts to hunt, or from a need for cats to supplement their diet. Cats are carnivores, and some cat foods might not be meeting all a cat’s needs, McDonald says. If either of these influence hunting behavior, then perhaps beefing up the amount of meat in a cat’s diet or mimicking hunting behavior through play could fulfill those needs without the collateral damage to wildlife.
2-12-21 'Hedge trimmer' fish facing global extinction
They are the most extraordinary of fish, resembling "hedge trimmers with fins". The sawfish, which is a kind of ray, is also among the most endangered of the fish living in the oceans. Once found along the coastlines of 90 countries, the animals are now presumed extinct in more than half of these, according to a new study. They are vanishing due to habitat loss and entanglement in fishing nets, experts have said. Their "saws", which evolved to sense and attack prey, have now become a liability, making them prone to being caught up in fishing gear. "Through the plight of sawfish, we are documenting the first cases of a wide-ranging marine fish being driven to local extinction by overfishing," said Prof Nick Dulvy of Simon Fraser University (SFU) in British Columbia, Canada. Of the five species of sawfish, three are critically endangered, while two are listed as endangered, according to the International Union for Conservation of Nature's (IUCN) Red List of Threatened Species. Previously widespread, the sawfish are now presumed extinct in 55 nations, the study said. There are 18 countries where at least one species of sawfish is missing, and 28 more where two species have disappeared. The list of countries where sawfish are extinct now includes China, Iraq, Haiti, Japan, Timor-Leste, El Salvador, Taiwan, Djibouti and Brunei. The US and Australia appear to be the last strongholds for the species, regarded as "lifeboat nations," where sawfish are better protected. The study, published in Science Advances, also identified eight nations where urgent action could make a big contribution to saving the species through conservation efforts. These are Cuba, Tanzania, Colombia, Madagascar, Panama, Brazil, Mexico and Sri Lanka. "While the situation is dire, we hope to offset the bad news by highlighting our informed identification of these priority nations with hope for saving sawfish in their waters," said Helen Yan of SFU. She said it is still possible to restore sawfish to more than 70% of their historical range, "if we act now".
2-12-21 Fin whale songs can reveal hidden features of the ocean floor
The sounds can penetrate Earth’s crust as seismic waves, illuminating its structure. The fin whale’s call is among the loudest in the ocean: It can even penetrate into Earth’s crust, a new study finds. Echoes in whale songs recorded by seismic instruments on the ocean floor reveal that the sound waves pass through layers of sediment and underlying rock. These songs can help probe the structure of the crust when more conventional survey methods are not available, researchers report in the Feb. 12 Science. Six songs, all from a single whale that sang as it swam, were analyzed by seismologists Václav Kuna of the Czech Academy of Sciences in Prague and John Nábelek of Oregon State University in Corvallis. They recorded the songs, lasting from 2.5 to 4.9 hours, in 2012 and 2013 with a network of 54 ocean-bottom seismometers in the northeast Pacific Ocean. The songs of fin whales (Balaenoptera physalus) can be up to 189 decibels, as noisy as a large ship. Seismic instruments detect the sound waves of the song, just like they pick up pulses from earthquakes or from air guns used for ship-based surveys. The underwater sounds can also produce seismic echoes: When sound waves traveling through the water meet the ground, some of the waves’ energy converts into a seismic wave (SN: 9/17/20). Those seismic waves can help scientists “see” underground: As the penetrating waves bounce off different rock layers, researchers can estimate the thickness of the layers. Changes in the waves’ speed can also reveal what types of rocks the waves traveled through. The echoes recorded in the Pacific Ocean revealed a classic ocean crust structure beneath three sites along the whale’s swim path: sediment layers between 400 and 650 meters thick atop a 1.8-kilometer-thick layer of basalt rock. Beneath that basalt lies a dense oceanic rock known as gabbro. The findings suggest that fin whale songs can be effective seismic tools to study the seafloor.
2-11-21 Numbats: Saving a marsupial 'unique even to Australia'
The numbat - a small and little-known Australian marsupial - is one of the world's most endangered animals. But conservationists are working hard to save them by building vast, predator-free sanctuaries.
2-10-21 Is our growing appetite for fish harming the planet?
Since 1950 the amount of fish we eat has risen by a staggering 750 per cent. While we take comfort in labels declaring our seafood "sustainable", tracing its true environmental toll tells a different story. THE fish counter at my local supermarket has a chalkboard displaying how many different species are on sale on any given day. It is usually in the 20s, though sometimes creeps above 30. As well as staples such as cod, salmon and mackerel, it often has trout, sea bass, monkfish, langoustines, tuna, scallops, squid, catfish and flatfish. The chiller cabinet next door has more: jellied eels and cockles in jars, mussels from Ireland, crab from Indonesia, prawns from Ecuador. In the canned goods section I can also find oysters from South Korea, crab meat from Vietnam, anchovies from the Pacific Ocean, sardines from the north Atlantic Ocean and tuna from the Indian Ocean. The freezers have yet more. This abundance makes my head swim. I don’t eat mammal or bird meat, but I do eat seafood, and I want to consume it as ethically and sustainably as possible. But I worry about overfishing and the environmental impacts of salmon farms and shrimp ponds. Most of the products on offer bear a label certifying that they were caught or farmed sustainably, or at least “responsibly”. What does that mean? Who checks? Is it even possible? In other words, can I eat fish with a clear conscience? Seafood is big business. Every year we collectively eat more than 155 million tonnes, about half of it wild-caught and half farmed. To put that in perspective, we eat about 320 million tonnes of land-reared meat a year. Yet consumption of fish is growing faster than that of meat – around 3.1 per cent a year versus 2.1 per cent. Since 1950, human population has grown by about 175 per cent. In that same time, the amount of fish we eat has increased by 750 per cent. This demand is sustained by a fleet of 2.9 million motorised fishing vessels and a vast and growing fish farming industry. More than half of the world’s oceans by surface area are now fished. Despite living on land, humans are a top marine predator.
2-10-21 Cannibal cockroaches nibble each other’s wings after they have mated
The key to a monogamous relationship is cannibalism – at least for wood-feeding cockroaches. This behaviour has probably evolved so these insects can keep partners around to help raise offspring. Most cases of sexual cannibalism involve creatures like spiders eating their suitors after mating. Males are often the victims, and eating them could help females fatten up on nutrients for use during pregnancy. Some male spiders will even sacrifice legs to aggressive females during mating. But males cannibalising females is rare, and mutual cannibalism even rarer. The case of this wood-eating cockroach species may be one of the only known examples of a species that practices mutual sexual cannibalism, says Haruka Osaki at Kyushu University in Japan. Osaki first noticed chewed wings on wood-feeding cockroaches (Salganea taiwanensis) that he caught in forests in Okinawa – the roaches range from Amani Island in Japan to Taiwan. To examine the phenomenon more closely, he and his colleagues collected wild cockroaches, divided them into 24 pairs, and video recorded them for three days in enclosures. They found that 12 of the pairs took turns consuming each other’s wings after mating. The cannibalism was usually preambled by a little foreplay in the form of licking, and the recipients didn’t appear to resist the love bites when they came, say the authors. The team also noted that the wings lack flesh, so wouldn’t provide much in the way of nutrition. “This wood-feeding cockroach must benefit somehow because this behaviour has evolved and maintained,” says Osaki. Osaki and his colleagues aren’t sure why, but they have a few ideas. These cockroaches usually mate with one partner for the duration of their life and stay together to raise multiple broods in galleries inside rotting wood. Clipping each other’s wings may encourage both partners to stick around to help raise offspring, especially as they are more easily exposed to predators outside their log. Or it could help them move around more easily in tight passages without getting stuck. Ridding themselves of body parts that can attract mites or mould might also help keep their brood cleaner and safer.
2-10-21 Female giraffes who hang out with friends live longer than loners
Adult female giraffes who spend time with lots of other females live longer than less sociable animals. Monica Bond at the University of Zurich, Switzerland, and her colleagues observed 512 female giraffes over 1500 square kilometres in the Tarangire Ecosystem in northern Tanzania. They surveyed the landscape six times a year between 2012 and 2016 and took photographs of any female giraffes they encountered. The team used a piece of software called WildID to identify giraffes from their spot patterns. Each giraffe is born with a unique pattern of spots and these remain unchanged throughout their life, says Bond. The researchers built a giraffe social network – based on similar research studying human ones – to map each female giraffe’s relationships with other females, the strength of these relationships and their average group size. From this, the team found that female giraffes that socialised in groups with at least three other females have a higher likelihood of survival than more solitary individuals. Sociability was also the largest contributor to survival, compared with other environmental factors including proximity to human settlements, food sources and vegetation type. “Friends matter for their survival,” says Bond. “We think it reduces stress in general for these female giraffes and allows them to live a more relaxed life.” This isn’t true of male giraffes. Previous research has shown that they are solitary animals that move around looking for females to mate with and don’t form stable, long-lasting relationships with other giraffes. “Mixing in small groups seems to foster the giving and receiving of information about where is best to feed,” says Daniel Rubenstein at Princeton University. Roaming with other females could also help the giraffes keep an eye out for predators and care for calves.
2-10-21 Vampire bat adopts orphan baby bat after untimely death of its mother
A female vampire bat has adopted an orphaned baby bat and begun nursing it, after creating a close social bond with the baby’s mother before she died. Although female bats live in “maternity colonies”, sometimes composed of hundreds of bats, they seem to raise their young individually rather than as a community. This rare observation of a bat adopting an unrelated infant gives further insight into the complexity of social relationships between individual bats, says Imran Razik at The Ohio State University. “The cool thing about vampire bats is they form these long-term social relationships with one another, which are in some ways comparable to human friendships,” says Razik. “With this adoption, something we don’t usually see, we’ve had the chance to contextualise this event very easily by having a recorded, long-term history of the social interactions [leading up to the adoption].” Razik and his colleagues at the Smithsonian Tropical Research Institute in Panama were studying the social behaviour of common vampire bats (Desmodus rotundus) at the time of the adoption. They captured 23 adult female bats from three wild colonies located hundreds of kilometres from each other, then put them together in a single captive colony to see how they developed relationships with strangers. Female vampire bats can form social bonds with other bats, grooming each other and sharing food by licking each other’s mouths. One bat fell ill during the study and died within weeks of giving birth. To the researchers’ surprise – and relief – another bat adopted the infant, says Razik. By viewing hundreds of hours of video recordings of their social interactions, the researchers could fully trace the development of the relationship between the sick mother bat (“Lilith”) and the adoptive bat (“BD”), who wasn’t pregnant or nursing. They had initially shown a lot of mutual grooming, suggesting they were bonding, says Razik.
2-10-21 Dragonflies do a backwards roll to fly upright – even when unconscious
When falling through the air in an upside-down position, dragonflies do backwards somersaults to return to an upright stance. They do this even when they are unconscious and – if their wings are propped open – when they are dead.Q These findings suggest that dragonflies are equipped with a potent mechanical design that keeps them right side up and airborne without any real effort. Such a passive flight-stabilisation mechanism could inspire better designs for small aircraft like drones, allowing for good stability and manoeuvrability “with less computational effort”, says Samuel Fabian at Imperial College London. “Passive stability lowers the effort requirements of flight, likely influencing the evolution of the dragonfly’s shape.” Fabian and his colleagues placed magnets and six motion-tracking markers on 20 male common darter dragonflies (Sympetrum striolatum) that they had trapped in the wild. They then placed the dragonflies, one by one, either right side up or upside down on platforms under magnets. By lifting the magnets, they dropped the dragonflies to study their falling technique using high-speed motion-capture cameras. Next, they chilled the dragonflies, essentially shutting them down into a torpor state, before dropping them again. “The animals were chilled on ice for 20 minutes, which effectively knocks them out and ceases much of their neural function for a while,” says Fabian. Finally, after each dragonfly died a natural death in the laboratory, they dropped it again, both with and without its wings propped up into the open, resting positions it used when it was alive. Reconstructed 3D models of the falling dragonflies showed that the alert ones somersaulted backwards when they were dropped upside down, says Fabian. Interestingly, the knocked-out dragonflies did the same thing, but more slowly.
2-10-21 A reeking, parasitic plant lost its body and much of its genetic code
The genome of Sapria himalayana is rife with gene loss and theft. For most of their lives, plants in the Sapria genus are barely anything — thin ribbons of parasitic cells winding inside vines in Southeast Asian rainforests. They become visible only when they reproduce, bursting from their host as a dinner plate–sized flower that smells like rotting flesh. Now, new research on the genetic code of this rare plant reveals the lengths to which it has gone to become a specialized parasite. The findings, published January 22 in Current Biology, suggest that at least one species of Sapria has lost nearly half of the genes commonly found in other flowering plants and stolen many others directly from its hosts. The plant’s rewired genetics echo its bizarre biology. Sapria and its relatives in the family Rafflesiaceae have discarded their stems, roots and any photosynthetic tissue. “If you’re out in the forest in Borneo and these [plants] aren’t producing flowers, you’re never even going to know they’re there,” says Charles Davis, an evolutionary biologist at Harvard University. For years, Davis has been studying the evolution of this group of otherworldly parasites, which includes the largest flower in the world, Rafflesia arnoldii (SN: 1/10/07). When some genetic data showed a close relationship between these parasites and their vine hosts, Davis suspected horizontal gene transfer. That’s where genes move directly from one species to another — in this case, from host to parasite. But no one had yet deciphered the genome — the full genetic instruction book — for these plants. So Davis and his team sequenced many millions of pieces of Sapria himalayana’s genetic code, assembling them into a cohesive picture of that species’ genome. When the team analyzed the genome, they found an abundance of oddities.
2-9-21 Whale threats from fishing gear 'underestimated'
The risk that whales can get entangled in fishing nets appears to have been underestimated, according to a new study. As many as 60% of blue whales in Canada's Gulf of St Lawrence have come into contact with fishing ropes and nets, based on scarring seen on photographs snapped by drones. Entanglement rates were similar in another ocean giant, the fin whale. Whales can suffocate or starve after getting tied up in fishing gear. An estimated 300,000 whales, dolphins and porpoises a year die after being injured in nets or lines designed to target other species. Reports of very large whales getting trapped in fishing gear are rare compared with smaller species, leading to the assumption that they aren't as much at risk. But a new study, led by experts at the University of St Andrews, Fife, casts doubt on this idea. The researchers analysed images taken by drones of blue and fin whales in Canada's Gulf of St Lawrence - an important summer feeding ground for whales. Scars on the tails of the whales suggest that 60% of blue whales studied and about half of fin whales had been entangled in nets at some point in their life. The researchers say more data is needed to assess the risks, as deaths from entanglement could tip some whale populations into decline. "These results will require a review of every recovery plan and strategy in which, so far, fishing was not listed as a significant threat for these two species," said Dr Christian Ramp of the University of St Andrews. In right and humpback whales, between 60% and 80% of the mammals have been entangled at least once in their lifetime. For the larger whales, like blue and fin, it had been previously assumed that this number was only around one in 10, because they are stronger and live further offshore, away from fishing fleets. Using drones, the team observed that at least 55% of the fin whales had scars from entanglement, and the range for the blue whales was similarly high at 40-60%.
2-9-21 Device that self-assembles in the uterus could limit wild horse births
Feral horse populations can be difficult to manage, but a new intrauterine device (IUD) that puts itself together with magnets inside the uterus could help sterilise mares and solve overpopulation issues. Current feral horse sterilisation techniques are impractical because they require darting each mare with contraceptive chemicals every year after an initial injection and five-week booster. “When you’re talking about hundreds of thousands of animals across a vast territory, keeping track of each individual mare’s schedule is just impossible,” says Carolynne Joonè at James Cook University in Australia. Joonè and her colleagues tested an IUD made of three polymer-covered magnetised parts that “find each other” and connect into a ring shape. Each part is 4 centimetres long and 1.6 centimetres wide, so they can be inserted without dilating the horse’s cervix, but the final ring shape is large enough that the IUD won’t fall out. That means they could prevent pregnancies in a horse for years, she says. To place them in feral horses, the mares would need to be captured and secured for the few minutes necessary to insert the parts through the cervix. But that’s still better than darting year after year, especially since horses are such “quick learners”, she says. “Their avoidance behaviour gets worse with time.” To see if this method could prevent pregnancies in feral horses, Joonè and her collaborators tested it in 14 university-owned female horses of a racing breed. They placed the IUD parts in seven of the mares, and artificially inseminated all 14 with sperm from the same fertile stallion. The IUD correctly assembled itself in all seven treated mares, and none of those horses became pregnant, while all seven of the mares without the IUD did. The horses had no major side effects from the IUD. “If it works like this in the brumbies [Australian feral horses], that would be great,” Joonè says. “It’s an option, and we need options at this stage.”
2-8-21 Decline of butterfly collecting hobby threatens conservation research
The decline of butterfly collecting as a hobby is making conservation research more difficult for entomologists, according to an analysis of 1.4 million specimens held in US museum collections dating from the 1800s. Although butterfly collecting is often seen as a pastime of Victorian-era gentlemen, Erica Fischer at King’s College London and their colleagues actually found that the largest growth in specimens occurred between 1945 and 1960, showing an 82 per cent increase. This may have been driven by college-educated veterans who received free tuition after the second world war, the researchers say. The number of specimens collected in the US then faltered in the 1960s, and plunged after 1990, the team found. Fischer says that instead of collecting physical specimens, amateurs these days are more likely to gather observational data, particularly photos posted to online databases. While useful, photos don’t let researchers analyse DNA, chemical ratios, internal organs or the pollen found clinging to specimens, says Fischer. For example, Heidi MacLean at Aarhus University in Denmark and her colleagues, in a study published in 2018, examined physical specimens of the Mead’s sulphur butterfly (Colias meadii) collected over the course of 60 years at Loveland Pass, Colorado, to see how they adapted to climate change by changing colour. “We couldn’t have done it without the actual specimens,” says MacLean. “Even though we used image analysis, the lighting and the background had to be the same for every specimen.” Fischer is now studying collections of butterflies and moths in UK museums to see if the same decline holds true and the cultural forces behind the change. “Is it that science has moved away from collections? Is it the professionalisation of science?” says Fischer.
2-5-21 Salt marsh fairy circles go from rings to bullseyes to adapt to stress
The most famous so-called fairy circles are grass-ringed patches of barren earth found in Namibia and Australia. Their lesser-known cousins – transient rings of plants found in Chinese salt marshes –could help explain why these patterns naturally form and may be indicators of ecosystems resilient to climate change. Previous research has shown that some self-organising patterns in nature provide insights into ecosystem resilience. But transient ones that change shape over time – for example, from spots to rings and then to concentric rings – haven’t been studied as much as persistent ones like fairy circles that mostly stay the same. To find out more, Li-Xia Zhao at East China Normal University and her colleagues took sediment and plant samples from transient rings on salt marshes in Shanghai. The rings were made up of two plant species, Scirpus mariqueter and Spartina alterniflora, and were generally between 10 and 100 metres in size. Compared with samples from the rings’ edges, centre samples had higher concentrations of sulphides, which can cause plant death at high levels. The centre samples also had less available soil nitrogen, which can limit plant growth. These variations at different positions in each ring are caused by the growth and decomposition of the plants. The researchers’ computer models show that both nutrient depletion and rising sulphide levels would lead the vegetation in the centre to die first, as that is where the plant has been growing for the longest, leaving living rings. These strange patterns of grass aren’t just interesting to look at – they indicate that their environment can bounce back from disruption more easily than others. The researchers’ models show that ecosystems with transient rings recover from disruptions like environmental stress – a lack of oxygen in the sediment, for example – to their previous state twice as quickly as those with persistent ring patterns.
2-5-21 A new chameleon species may be the world’s tiniest reptile
Found in Madagascar, Brookesia nana is less than 30 millimeters long. Hidden beneath the leaf litter of a northern Malagasy forest lives a chameleon so slight that it could tumble off the tip of your finger. Measuring just under 30 millimeters from snout to tail, the newly described species, Brookesia nana, may be the smallest reptile on Earth, researchers report January 28 in Scientific Reports. Just two adult specimens, a male and female, are known. The female measures 28.9 millimeters, considerably larger than the 21.6-millimeter-long male. The size difference may have driven the male’s genitalia to be quite large — nearly 20 percent of its body length — to be a better fit to his mate, herpetologist Frank Glaw of the Bavarian State Collection of Zoology in Munich and colleagues suggest. Dubbed B. nana for its nano size, the species belongs to a genus of at least 13 other small chameleons spread out across the mountainous forests of northern Madagascar. Why B. nana and its cousins shrank to such minuscule proportions remains a mystery, though smallness does have its benefits: There’s some evidence that small chameleons are especially good shots with their ballistic tongues. In daylight, Brookesia chameleons scour the forest floor, snatching up mites and other small invertebrates, Glaw’s team suspects. At night, the lizards retreat upward, gripping blades of grass or other plants for safety. Deforestation and habitat degradation threaten B. nana’s future, the researchers say, though the region where the compact chameleons were found was recently designated a protected area by the Malagasy government. The species may soon be listed as critically endangered, the gravest rating made by the International Union for Conservation of Nature.
2-5-21 'Smallest reptile on earth' discovered in Madagascar
Scientists believe they may have discovered the smallest reptile on earth - a chameleon subspecies that is the size of a seed.. Two of the tiny lizards were discovered by a German-Madagascan expedition team in Madagascar. The male Brookesia nana, or nano-chameleon, has a body of just 13.5mm. This makes it the smallest of about 11,500 known species of reptiles, according to the Bavarian State collection of Zoology in Munich. Its length from top to tail is 22mm (0.86in). The female is far bigger at around 29mm, the institute said, adding that other specimens were yet to be located, despite "great effort". "The new chameleon is only known from a degraded montane rainforest in northern Madagascar and might be threatened by extinction," said the Scientific Reports journal. Oliver Hawlitschek, a scientist at the Center of Natural History in Hamburg, said: "The nano-chameleon's habitat has unfortunately been subject to deforestation, but the area was placed under protection recently, so the species will survive." Researchers found that it hunts for mites on the rainforest floor and hides from predators at night in blades of grass. In a blog post, Dr Mark Scherz, one of the researchers involved in the discovery, called it "a spectacular case of extreme miniaturisation". The forests where the Brookesia were located are still well connected with others across the north of the island, he said. "So this tiny new chameleon violates the pattern of the smallest species being found on small islands. That suggests that something else is allowing/causing these chameleons to miniaturise," he added. In their report, scientists recommended that the chameleon be listed as critically endangered in the International Union for Conservation of Nature's (IUCN) Red List of Threatened Species to help protect it and its habitat.
2-5-21 The animals that ticks bite in the U.S. South can impact Lyme disease spread
In the South, ticks attach more often to skinks, which don’t pass on Lyme bacteria as well as mice. The paucity of Lyme disease cases in the southern United States may be partly due to what black-legged ticks in southern locales bite. Although black-legged ticks (Ixodes scapularis) claim much of the eastern half of the country as their home, the Lyme disease they spread is largely concentrated in the Northeast and increasingly in the upper Midwest. It’s well known that ticks in the Northeast commonly latch on to white-footed mice. This relationship turns out to be a boon for Lyme disease. When infected with the bacteria Borrelia burgdorferi, which causes Lyme disease, these mice very efficiently spread it to the ticks, which can then pass it on to people. But southern-residing ticks are different. They are more likely to bite lizards called skinks, which are poor transmitters of the bacteria, researchers report January 28 in PLOS Biology. This study “shows that there’s this really interesting switch” north to south in the predominant tick host, says disease ecologist Shannon LaDeau of the Cary Institute of Ecosystem Studies in Millbrook, N.Y., who was not part of the research team. “It looks like that is reducing the transmission” in the South of the bacteria that causes Lyme disease. An estimated 476,000 people are diagnosed with Lyme disease each year in the United States, according to insurance data from 2010 to 2018. In about 70 to 80 percent of cases, a rash in the area of the tick bite is an early sign of the disease; other symptoms include fever, fatigue and achiness. Most people recover with early antibiotic treatment. If the diagnosis is missed, the infection can spread in the body and cause arthritis and nerve pain (SN: 6/22/19).
2-5-21 Some mouse sperm try to sabotage rivals in race to fertilise the egg
Sperm have one goal – to reach the egg and fertilise it – and it seems that some mouse sperm cells carrying a certain genetic mutation may boost their chances of doing so by sabotaging their rivals. Bernhard Herrmann at the Max Planck Institute for Molecular Genetics in Berlin, Germany, and his colleagues analysed sperm samples from mice. They found that sperm from some mice, carrying a genetic variant called the t haplotype, move faster and swim in straight lines. Other sperm without this variant from the same mice swim less productively, often moving slower and in circles. Previous research has shown that mice with two copies the t haplotype genetic variant are more likely to be infertile, but this new study suggests that males with one copy of the genetic variant produce these t haplotype sperm cells that are more motile than those without. This t haplotype genetic variant is a “selfish” genetic element, because it can increase its likelihood of being passed on to offspring to higher than the usual odds of 50 per cent, and now Hermann and his team have figured out how these sperm gain their advantage. The sperm cells carrying one t haplotype variant produce certain molecules that are able to disturb other sperm cells. The gene variants make it difficult for the rival sperm cells to interact with their environment, blocking various cell signalling molecules that normally provide the sperm with a sense of direction. Although the t haplotype sperm cells were more motile as a result of this competitive edge, the researchers did not test their ability to fertilise an egg. The team also found a link between sperm success and an important protein in the body called RAC1, which plays a role in general cell movement and directs the sperm cell towards the egg. The levels of RAC1 in the body have to be just right – too high or too low and the sperm cells won’t move straight.
2-4-21 Orangutans create new ways to communicate with each other in captivity
What’s in a somersault? A flap of the lip, a spit of water in the face? More than meets the eye, it seems. They may all be new ways of communicating that orangutans have come up with in captivity. This suggests that such gestural creativity may be ancestral in the great ape line, adding a new piece to the puzzle of language evolution. Using new expressions to convey things – known as productivity in linguistics – is one of the fundamental building blocks of complex language, and it is rarely reported in the animal kingdom. Instead, most animals have a fixed set of messages, the meanings of which are determined by the context – such as the arrival of a predator. These signals seem to be innate rather than being learned, and have formed through a long process of natural selection. Humans clearly show productivity, but whether other apes do is debated. To explore, Marlen Fröhlich at the University of Zurich in Switzerland and her colleagues looked at the question from a new angle, by exploring whether orangutans held in captivity in zoos have developed new ways to communicate not seen in their wild peers. Zoos offer orangutans a stable yet different ecological niche. Getting food is less of an issue, as is avoiding predators. In the wild, orangutans tend to live rather solitary lives. In zoos, they live in larger groups in close proximity to one another, with more social interaction. They spend more time on the ground, away from foliage that can disrupt their view of other orangutans. All of these factors may help establish an environment where productivity can flourish. Fröhlich’s team suggests that zoo living really has made a difference. The group looked at information on more than 8000 examples of non-vocal orangutan communications by 30 individuals at five zoos, and 41 in wild populations in two forests – one in Sumatra and one in Borneo.
2-4-21 Bats soar to heights of 1600 metres by riding late night winds
Bats can get lift from their landscape. The flying mammals surf on air currents, which sweep upwards as they hit hills or slopes, to reach altitudes of up to 1600 metres. Birds do this too, but it wasn’t clear whether nocturnal bats could take advantage of the technique given that winds are a lot less active in the night sky. Riding thermals is relatively easy for a bird flying during the day, says Teague O’Mara at Southeastern Louisiana University. “Because the sun heats up the landscape, there’s rising warm air. Winds come in and lift and push birds through,” says O’Mara. Birds also benefit from long-distance visibility, which may allow them to “read” and exploit the landscape. “But at night the energy in the atmosphere drops, and the wind drops, and there’s just not a lot going on,” he says. Even so, prior studies have shown that bats can soar to great heights on night flights, so O’Mara and his colleagues set out to discover how they do it. The researchers studied a maternity colony of European free-tailed bats (Tadarida teniotis) in northeastern Portugal. Using lightweight GPS collars or backpacks, they gathered high-resolution GPS data from eight lactating female bats on night flights. The researchers also built a digital model containing information on the local topography and weather patterns. They found that the bats sought out hillsides and cliffs with south or west-facing slopes, where they could benefit from prevailing night-time winds that sweep up these slopes upon meeting the topography. This strong upward push allowed the bats to gain altitude while using very little energy, says O’Mara. The bats would then dip back down towards the ground and find a new slope that would allow them to rise again, repeating the process many times – making a flight path reminiscent of a roller-coaster ride, the team writes.
2-4-21 How a tiny spider uses silk to lift prey 50 times its own weight
Spinning the right lines can accomplish feats of strength when muscle isn’t enough. A family of spiders can catch prey many times their own weight by hitching silk lines to their quarry and hoisting the meaty prize up into the air. Tangle web spiders, in the Theridiidae family, are masters of using silk to amplify muscle power. Their webs are “a messy tangle,” says Gabriele Greco, who studies biological materials at the University of Trento in Italy. Silk strands slant and crisscross in a cobwebby scribble. Filming how spiders hunt from such snarls, Greco and Trento colleague Nicola Pugno focused on the most spectacular scenarios: attacks on insects that weighed up to 50 times as much as the spiders themselves. The web makers, however, could win their battles, thanks to adroit fighting, venom and lots of prey-wrapping silk. Victorious spiders also attached multiple silk threads to their prey bundle to haul the feast up to the web, Greco and Pugno report February 3 in Journal of the Royal Society Interface. Yet oddly these threads never get pulled totally taut. To analyze the spiders’ weight-hauling moves, the researchers set up lab boxes with black walls for easy observation of white silk. Inside each box went a Theridiidae species, either a triangulate cobweb spider (Steatoda triangulosa) or a false black widow (S. paykulliana). In the wild, both species stretch some strands from the tangle down to the ground, anchoring the strand’s sticky end. When some small, edible creature such as an ant bumbles against the strand, it breaks loose from the ground and yanks the tiny morsel upward to flail helplessly in the air. Lunch! What really interested Greco and Pugno, however, were reports of these strands occasionally catching “giant” prey, including a snake and a mouse. To give the food-catching silk an extreme workout, researchers used big cockroaches.
2-3-21 Australian government may use herpes virus to control invasive carp
The Australian government is considering using a type of herpes virus as a biological agent to reduce the population of carp in the country’s waterways. Since its introduction to Australia in the late 1960s, the common carp (Cyprinus carpio) has become an ecologically destructive species. “Their main impact has been a decline in biodiversity. Native fish and native water plants have declined,” says Ivor Stuart at the Arthur Rylah Institute for Environmental Research, the biodiversity research organisation for the state government of Victoria in Australia. He and his colleagues have now estimated the size of the problem. They calculated that, in a year with average rainfall, the population of carp in Australia is roughly 199.2 million – equivalent to 215,450 tonnes of fish. “Carp tend to impact the amenity and biodiversity of an aquatic system when they reach 80 to 100 kilograms per hectare,” says Stuart. The researchers found that carp exceed this threshold for biodiversity impact in 54 per cent of wetlands, 70 per cent of rivers and 97 per cent of large lowland rivers. The estimate was calculated from a database the team created, which was based on 574,145 carp caught at 4831 sites between 1994 and 2018. The researchers also incorporated data from 153 research studies. Current local control measures include carp-separating cages, which can automatically sort carp from other fish species using the fact that carp – unlike many species – will jump out of the water when stressed. The devices encourage carp to jump into a cage that non-jumping fish are unable to reach. But while these devices reduce numbers, they aren’t enough to mitigate the damage that carp do, says Stuart. The Fisheries Research and Development Corporation (FRDC), on behalf of the Australian government, is currently assessing how feasible it would be to use cyprinid herpesvirus 3 as a broader biocontrol strategy.
2-3-21 Bats that eat insects should be able to taste sweet food but can't
Bats that eat insects are unable to taste sweet foods, even though they have the genetic ability to do so. The evolution of taste perception and diet are closely linked for many animals, but in some cases this link is unclear. Different species of bat have highly diverse diets, ranging from nectar to insects and even blood, despite having similar taste receptor genes. To discover more, Huabin Zhao at Wuhan University in China and his colleagues sequenced two sweet taste receptor genes in 34 bat species. They found that all the bats expressed both genes, meaning their tongues contain the receptor proteins. They then tested the food preferences of two of the species, the insectivorous Rickett’s big-footed bat (Myotis ricketti) and the Leschenault’s rousette fruit bat (Rousettus leschenaultii). This involved placing two bottles in a cage with each bat, one filled with their usual food, the other with a mixture of their food and sugar. The team found that the fruit bats had a strong preference for the sweet food, but the insectivorous bats didn’t. “This is surprising because these two species have similarly conserved sweet taste receptors genes which are expected to show similar sensitivity to sugar,” says Zhao. The researchers also directly tested the activity of these receptors by expressing them in living cells. They found that in fruit bats, the sweet taste receptors responded to natural sugars, but the same wasn’t true for insectivorous bats, suggesting a loss of sweet taste. This makes sense because insects contain little sugar, so insectivorous bats don’t have much to lose by evolving this sense away. “This relaxes the functional constraint on the sweet taste receptor, which eventually resulted in the loss of sweet taste in insectivorous bats,” says Zhao, supporting the idea that taste perception is shaped by an animal’s feeding preference.
2-3-21 Traffic noise impairs songbirds' abilities
A test of songbirds' problem-solving skills has revealed how traffic noise impairs the animals' abilities. Scientists set zebra finches a "battery of foraging tasks" in the presence or absence of the noise. They found that the sound of passing cars diminished the birds' ability to find food. The results, published in the journal Proceedings B, suggest that noise pollution has "previously unconsidered consequences for wildlife". Prof Christopher Templeton from Pacific University in Oregon, US, led the study, which he carried out in a behavioural lab with zebra finches. The researchers set the birds the tasks both in a quiet setting and while a recording of road traffic was played. "Just hearing a car drive by is enough to really affect their performance," explained Prof Templeton. The tasks were designed to mimic problem-solving and foraging (finding and gathering food) in the wild. One involved retrieving food from beneath leaf-like "lids" that the birds had to flip over to reveal the reward. In another test, the birds had to work out the way into a cylinder that had a piece of food inside. "They're almost twice as likely to do [the foraging tasks] correctly if they don't hear traffic noise," explained Prof Templeton. "I think these results are going to be pretty widely applicable to other species," he continued. "While the zebra finches might live in a lab, it's anything but quiet. You can imagine a colony of a whole bunch of birds making sounds all the time - it's pretty noisy." There is mounting evidence that human-made noise has a variety of negative effects on wildlife. One study found that birds have actually changed their songs during the relatively quiet period of lockdown. And even in the deep ocean, the noise of sonar, seismic surveys and shipping can disrupt animal communication.
2-3-21 Genetics leaves little doubt that humans wiped out passenger pigeons
The eye-catching birds of North American that went extinct during the last century weren’t experiencing genetic decline before their disappearance – which suggests humans were probably responsible for their extinction. “These charismatic species that went extinct in the early 1900s – and one of them in 1988 – appear to have been doing just fine historically over tens of thousands of years, until European colonisation [of North America],” says Brian Tilston Smith at the American Museum of Natural History in New York. The only parrot native to the US, along with a woodpecker, the passenger pigeon, the prairie chicken and a warbler, were among the colourful birds that once roved the New World in abundance before recently – and dramatically – dying out, says Smith. To learn more about why they did so, Smith and his collaborators ran DNA sequencing on 100-year-old skin samples from conserved birds in the American Museum of Natural History, representing five recently extinct species: the heath hen (Tympanuchus cupido cupido), the passenger pigeon (Ectopistes migratorius), the ivory-billed woodpecker (Campephilus principalis), the Carolina parakeet (Conuropsis carolinensis), and the Bachman’s warbler (Vermivora bachmanii). Specifically, they examined genetic markers from numerous individuals representing various geographic areas of the eastern part of North America, which would help tell the story of the species’ demographic past. To compare with similar species that haven’t gone extinct, the researchers also sampled century-old museum collection skins of the northern bobwhite (Colinus virginianus), the eastern screech owl (Megascops asio), the mourning dove (Zenaida macroura), and the hairy woodpecker (Dryobates villosus).
2-3-21 Some spiders use their silk to hoist helpless prey so it cannot escape
Some spiders take on prey that is far larger than they are, including lizards. To stop such prey from running away, they use their webs as pulleys to lift the doomed animals off the ground. Gabriele Greco and Nicola Pugno at the University of Trento in Italy used high-speed video to watch five captive spiders from the Theridiidae family catch cockroaches up to 50 times more massive than themselves. These are the most common type of spider found in human homes. The researchers found that the spiders seemed to be using their body weight to put tension on the silk threads to keep them taut before attaching them to the cockroaches. The spiders then continued to attach more and more threads to their prey until it was lifted into the air. “In the end, all these threads create enough tension to lift the prey, and that is when the spider wins,” says Greco. “Then the prey cannot escape because it cannot grab the surface below.” Once the prey is off the ground and unable to run away, the spider can take its time to kill and devour it. The researchers found that the silk didn’t stretch much during lifting, possibly because the spiders had already stretched it out before attaching it to their prey. This allowed the threads to recover when the cockroaches struggled instead of permanently sagging. “This silk used to lift the prey, it’s very strong, comparable to steel, but it is as elastic as the normal silk you would use to make clothes,” says Greco. This is interesting because you might not expect such a relatively simple animal to know how to use tools to catch its prey in such a sophisticated way, he says. It may allow spiders to have an outsized impact on their ecosystems by eating all sorts of small animals instead of just bugs.
2-2-21 Bottom trawling ban for key UK fishing sites
Two of the UK’s most sensitive fishing sites are set to receive better protection. The Marine Management Organisation says it plans to safeguard fishing areas in Dogger Bank and South Dorset by completely banning bottom trawling. The sites are already designated as protected areas, but in reality they are not patrolled - and they’re both over-fished. Greenpeace recently dropped concrete blocks on to Dogger Bank. The intention was to deter bottom trawling. Another group, Blue Marine, took legal action to try to safeguard the sea bed. Bottom trawling is a destructive type of fishing which involves dragging weighted nets across the sea floor. The MMO is consulting on proposed by-laws prohibiting bottom-towed gear on the sites. The consultation runs to 28 March 2021. The Environment Secretary George Eustice said: “Now that we have left the Common Fisheries Policy, we are able to deliver on our commitment to achieve a healthy, thriving and sustainable marine environment.” The decision couldn’t have been made if the UK was still in the EU, and it was condemned by the National Federation of Fishermen's Organisations (NFFO). A spokesperson for the NFFO said: “The decision has been taken with zero discussion with those affected. There will be knock on environmental as well as social and economic impacts.” Dogger Bank is the largest sandbank in UK waters, and underpins the North Sea’s ecosystem. It provides a vital habitat for a wide range of species which live on and within the seabed, including flatfish, starfish, sandeels, crabs, clams, worms, scallops and more. These species in turn provide a vital food source for predators such as porpoises, dolphins and seabirds. Bottom trawlers typically seek scallops, sandeels, sole, plaice, cod, and crab. The UK government has also proposed to partially stop bottom trawling at two other theoretically protected sites – one off the coast of Land’s End and the other off Lincolnshire.