6-24-19 Hundreds of orcas hold an annual meeting and now we may know why
At the same time every year around 150 orcas meet 50 kilometres off the south coast of Australia, and now we may know why. The orcas are attracted to an abundance of squid to feast on, funneled there by a special configuration of narrow canyons. The extraordinary congregation happens between January and April and the orcas spend their time feeding and playing in a surprisingly deep patch of water around 20 kilometres across and around 1 kilometre down. Initially, researchers were puzzled that the orcas found that particular region so appealing as the surrounding ocean is low in nutrients. Jochen Kaempf at Flinders University, Australia, suspected the geometry of the ocean floor might hold the answers. He and his colleagues found deep and narrow canyons slicing into the continental shelf under the surface. And using computer modelling they discovered that a current running along the southern coastline would concentrate waters through the contours of the canyons and out as a narrow stream toward the orcas’ feeding ground. “This region hence serves as a ‘bottleneck’ for all marine species,” says Kaempf. Some of these are squid, which are a typical food source for orcas, but giant squid that live in the ocean depths may also get swept up. Kaempf says this may explain some of the spectacular feeding frenzies that are observed when these fearsome predators are joined by sharks and flocks of birds as they feast on a much larger marine animal. According to modelling and observational data, the influence of a separate current emerges in April and suppresses the upwelling. This means squid are no longer funnelled into that region, and explains why orca numbers start to dwindle in April. This phenomenon may also explain why many other orca hotspots exist near certain submarine canyons in the world, Kaempf says.
6-22-19 'Friendly' bacteria could help save frogs from disease
Bacteria living on the skin of frogs could protect them against a deadly virus, according to research. The work by scientists at the University of Exeter and Zoological Society of London could help save species such as the European common frog from being wiped out by a disease. Amphibians have been hit particularly hard by changes in the natural world. Up to 40% of species are close to dying out due to factors such as pathogens, habitat loss and climate change. The British scientists looked at how common frogs are coping with ranavirus, which can kill a large number of frogs in a short time in UK ponds. They found a link between outbreaks of the disease and the make-up of bacteria on the frogs' skin in different populations across southern England. This gives the first demonstration that in the wild there is a correlation between populations that get disease and populations that remain disease-free, and the mix of bacteria on the skin, said Dr Lewis Campbell from the University of Exeter. "It's a silver bullet against the virus, potentially," he said. The researchers hope the work could help save the frog species most often seen in UK ponds. There is growing evidence that skin bacteria may protect amphibians from chytrid fungus, another deadly frog disease which is common around the world. Cocktails of so-called friendly bacteria are being developed that might help protect frog species. "Our work suggests that given enough effort and research, similar probiotic therapies may be effective against ranavirus," said Dr Xavier Harrison also from the University of Exeter. The research is published in the journal, Frontiers in Microbiology.
6-21-19 Death of mother prompts adolescent chimps to look after their siblings
Adolescent chimpanzees adopt their younger siblings if their mothers die. The older siblings keep a close watch on the youngsters, protect them from threats, and give them lots of comforting snuggles. The finding adds to the evidence that chimpanzees can understand when others are suffering, and to some extent can help them. In line with this, a second study shows that chimpanzees have a strong emotional response when they see that another chimp, or a familiar human, is injured. “After individuals lose their mothers, they do receive attention from other individuals in their group, who are often their siblings,” says Rachna Reddy of the University of Michigan. She has now studied the adoptions in detail. Reddy was tracking a group of about 200 chimps in Kibale National Park, Uganda, when they were struck by a respiratory disease between December 2016 and February 2017. During the outbreak, 25 chimps died and 13 lost their mothers. Chimps spend their first five years being carried and nursed by their mothers, and another three staying close to them. They are then adolescents roughly from eight to 15 years old. Of the orphaned chimps, nine were under the age of 12, meaning they were adolescents or younger. Reddy followed four pairs of young chimpanzee siblings, where the older of the two effectively adopted the younger. The older chimps were 10-17 years old, while the younger siblings they adopted were 6-7 years old. Compared to the period before their mothers’ deaths, the pairs spent much more time together. They also groomed, reassured and consoled each other. “It was like they were both seeking physical contact all the time,” says Reddy. “They were sort of inseparable.”
6-21-19 Parasites ruin some finches’ songs by chewing through the birds’ beaks
Gaping gaps may create discord for male birds wooing a mate. Invasive parasites in the Galápagos Islands may leave some Darwin’s tree finches singing the blues. The nonnative Philornis downsi fly infests the birds’ nests and lays its eggs there. Fly larvae feast on the chicks’ blood and tissue, producing festering wounds and killing over half of the baby birds. Among survivors, larval damage to the birds’ beaks may mess with the birds’ songs when they’re older, possibly affecting their appeal to potential mates, researchers report June 12 in Proceedings of the Royal Society B. “What’s heartbreaking, when you’re walking through this beautiful forest, is to hear these medium tree finch males just singing and singing and not being able to attract a mate,” says Sonia Kleindorfer, a behavioral ecologist at Flinders University in Adelaide, Australia and the University of Vienna. The fly arrived in the Galápagos probably in the 1960s. The researchers studied two finch species on Floreana Island that the fly larvae plague: the critically endangered medium tree finch (Camarhynchus pauper) and the related small tree finch (C. parvulus). In one life stage, the larvae reside in the birds’ beaks, where they chew up the keratin and soft tissue, enlarging the birds’ nostrils, called nares. Kleindorfer and colleagues wondered how this impacts the birds’ song and the sexual selection that results from it. So the scientists captured finches, measured their nares and then tagged and released them back into the wild. Then, the researchers recorded and analyzed the songs of 77 birds. The medium tree finch usually makes a more metallic bell-like sound, while the small tree finches’ lower-pitch tune sounds like “cha cha cha,” Kleindorfer says. But in both species, birds with the most deformed beaks sang at a lower pitch than birds with normal beaks.
6-21-19 Canada becomes the first G20 country to ban shark fin trade
Canada has become the first G20 nation to ban the import and export of shark fins, in an effort help preserve a predator under threat. The country is the largest importer of shark fins outside Asia, though shark finning in the domestic fishery has been illegal since 1994. The shark fin trade is believed to have contributed to the precarious status of many shark species worldwide. An estimated one-third of fins sold come from species that are at risk. Critics say the way many of the fins are collected is inhumane and unsustainable and has had a devastating impact on global shark populations. Shark finning involves cutting off the valuable fin while the shark is alive, and discarding the rest of the body. Canada's bill bans the import and export, to and from Canada, of shark fins that are not attached to the shark. It was passed by parliament this week after years of effort by legislators and campaigners, and received Royal Assent on Friday. Fins are some of the most expensive seafood items in the world, as the meat is considered a delicacy. In 2018, Canada imported over 148,000 kg (326,000 lbs) of shark fins. "We're not the biggest player but we're a player," executive director Josh Laugren, with Oceana Canada, which lobbied for the legislation, told the BBC. "[The bill] is both meaningful in its own right in terms of the trade of shark fins but also hopefully leads the way for other countries to follow suit." The UN estimates that 73 million sharks are killed for their fins every year. Like in Canada, conservation concerns have led to a push to limit the trade of shark fins in other countries. In the US, there are trade bans in place in states like Washington, Oregon, California, and Texas. Congress is also considering legislation on the matter. There is also evidence that public awareness campaigns can have an impact on shark fin consumption.
6-20-19 U.S honeybees had the worst winter die-off in more than a decade
Varroa mites and diseases did the most damage, but weather disasters didn’t help. U.S. honeybees just weathered an unusually bad winter. About 38 percent of beekeepers’ colonies died between October 1, 2018, and April 1, 2019, the Bee Informed Partnership estimates. While it wasn’t the worst recent year overall for honeybee losses — that was 2012–2013 — preliminary results released June 19 show it is the worst winter die-off recorded over the University of Maryland–based nonprofit’s 13 years of surveying bee populations. Beekeepers should be able to rebuild those numbers this year, but such ongoing winter losses raise deep worries about the future of crop pollination. On average over the 13 years, about 29 percent of colonies have died each winter. The 2018–2019 numbers came from nearly 4,700 beekeepers, representing about 12 percent of the estimated 2.69 million U.S. hives. Some floods and fires this year destroyed colonies, but “the take-home worry for me is Varroa [mites],” says the Partnership’s Dennis vanEngelsdorp, a bee-health entomologist at the University of Maryland in College Park. The invasive mite species Varroa destructor clamps its tiny pimple-shaped body onto bees just as they’re turning into adults (SN: 2/16/19, p. 32). Mites sap bee strength and spread disease, yet remedies against the pests seem to be losing their power. “Ideally in the long-term, we would have a bee that was resistant,” vanEngelsdorp says. While winter bee colony die-offs are worrisome, beekeepers can split surviving bee colonies and add new queens. Replacing winter-killed colonies this way, however, takes labor, time and money.
6-20-19 The world’s fisheries are incredibly intertwined, thanks to baby fish
A new study underlines the need for global cooperation in managing stocks, researchers say. Marine fisheries are typically managed by individual nations. But the fish in those stocks often originate elsewhere, according to a computer simulation of how eggs and larvae from hundreds of fish species ride ocean currents around the world. That finding means that many nations with economies that rely on fishing must depend on other countries to maintain important spawning grounds. The results of the simulation highlight the importance of international cooperation in sustaining the fisheries that provide millions of people with food and livelihoods, researchers report in the June 21 Science. Oceanographer Nandini Ramesh of the University of California, Berkeley and colleagues simulated ocean currents transporting the eggs and larvae of more than 700 species of commercially harvested fish among 249 national fishing grounds. More than 90 percent of the world’s fish are caught within these marine territories, which extend a few hundred kilometers off the shores of coastal nations. The simulation accounted for when and where different species lay eggs, as well as the speeds and directions of ocean currents throughout the year. A vast network of larval flows connects fisheries across the globe, the researchers found. In 114 national territories, at least 1,000 tons of catch per year originates from elsewhere. Many countries, from Indonesia to Norway to Mexico, harvest hundreds of thousands of tons of fish born outside their jurisdictions. For Russia and South Korea, that catch exceeds 1 million tons.
6-20-19 Mice and bats’ brains sync up as they interact with their own kind
Studies of the two mammals show coordinated neural activity. When animals are together, their brain activity aligns. These simpatico signals, described in bats and mice, bring scientists closer to understanding brains as they normally exist — enmeshed in complex social situations. Researchers know that neural synchrony emerges in people who are talking, taking a class together and even watching the same movie. But scientists tend to study human brains in highly constrained scenarios, in part because it’s technologically difficult to capture brain activity as people experience rich social interactions (SN: 5/11/19, p. 4). Now two studies published June 20 in Cell offer more details about how synced brains might influence social behavior. In one study, researchers monitored a pair of Egyptian fruit bats in a dark chamber for more than an hour. Neural implants recorded brain activity as the bats groomed themselves, fought, rested and performed other behaviors. The brain activity of the two bats was highly coordinated. When one bat’s neural activity oscillated in a fast rhythm, for example, the other bat’s brain was likely to do the same thing. This coordination continued even when the bats weren’t directly interacting with each other, the team found. But when the bats were separated into two chambers in the same room, this correlated activity fell away, suggesting that the bats had to be sharing the same social context for their brains to link up. A similar result came from a study in mice. As with the bats, when two mice were separated, their brain activity was no longer coupled, researchers report.
6-20-19 Weird whale may be a hybrid of a narwhal mother and beluga father
The first evidence has been uncovered to show two of the Arctic’s most majestic marine creatures mated together. DNA analysis of an unusually shaped whale skull in a Danish museum suggest the creature was a hybrid born of a mother narwhal, known as unicorns of the sea for their tusks, and a father beluga whale, dubbed sea canaries for their vocal nature. Killed by a hunter in West Greenland during the 1980s, the animal’s skull was collected by researchers in 1990, prompting a hypothesis that it was a narwhal-beluga hybrid. A Danish and Canadian team have now provided the data to confirm the idea, with genetic sequencing comparing it to live animals from the same area showing it to be 54 per cent beluga whale and 46 per cent narwhal. The results indicate it is a first generation hybrid male. While it is rare for animals to mate with other species, narwhals and belugas belong to the same family, Monodontidae. Eline Lorenzen of the Natural History Museum of Denmark says the main challenge was there was so little DNA left in the specimen. “[But] there are methods available now to get insights even with super low data,” she says. The hybrid did not have the narwhal’s distinctive tusk and had a different arrangement of teeth to its parents, but beyond that we know little of how the creature would have looked. Lorenzen says that reports from the hunter say the animal was evenly grey in colour, had flippers shaped like those of belugas and a tail shaped like a narwhal. Concentrations of carbon and nitrogen found in the skull implies the hybrid ate different food from its parents, feeding on those near the sea floor.
6-20-19 DNA confirms a weird Greenland whale was a narwhal-beluga hybrid
Genetic analysis of the animal’s skull shows it had a narwhal mom and beluga dad. Researchers have made a whale of a discovery — a hybrid of a beluga whale and a narwhal. DNA analysis of the whale’s skull confirmed it to be the male offspring of a narwhal mother and a beluga father, researchers report June 20 in Scientific Reports. The animal was one of three unusual whales caught during a subsistence hunt in 1986 or 1987 in western Greenland’s Disko Bay, and the only one with any known remains. The three whales were all uniformly gray, with pectoral fins shaped like belugas’ and tails shaped like narwhals’. The Inuit hunter, who gave the skull to researchers, said that he’d never seen such odd whales before or since, says Eline Lorenzen, an evolutionary biologist and curator of the National Museum of Denmark at the University of Copenhagen where the skull is housed. Disko Bay is one of the few places where belugas and narwhals overlap during mating season. Previous DNA analysis of the decades-old skull was “lousy,” Lorenzen says. So she and colleagues used techniques for analyzing ancient DNA to determine that the animal had a roughly 50-50 mix of beluga and narwhal DNA, making it a first-generation hybrid (SN: 11/11/17, p. 16). There’s no way to tell whether the hybrid whale was fertile. Analysis of isotopes, heavier or lighter variants of certain atoms, suggests that the hybrid may have had different feeding patterns than either parent species.
6-20-19 Russia to release whales from 'jail' in far east after outcry
Russia has started to release a group of nearly 100 captive whales which have been kept in small pens in the far east of the country. It comes after the so-called "whale jail" provoked an international outcry, with marine scientists and celebrities calling for the mammals to be released. In total, 11 killer whales (orcas) and 87 belugas are being kept in cramped enclosures on the Sea of Japan. They will be released in stages and the process will take several months. "We have taken the only sensible decision at the recommendation of scientists to release the animals to their natural habitat where they were caught," Deputy Prime Minister Alexei Gordeyev told reporters on Thursday. "This operation will take about four months," he added. Eight whales will reportedly be freed in the first stage of the process. President Vladimir Putin praised the decision during his annual televised phone-in in which he fields questions from members of the public. "The killer whales alone - as far as I know - are worth around 100 million dollars," he said. "When it's big money, problems are always hard to solve. Thank God things have started moving." The juvenile whales were caught last year in the Sea of Okhotsk. They were then transported more than 1,300km (800 miles) south and kept in cramped pens near the port town of Nakhodka. Although Russia allows the capture of whales for scientific purposes, experts feared the animals were bound for theme parks or aquariums in China. Individual orcas, often caught illegally, can fetch millions of dollars. Belugas are sold for tens of thousands of dollars. Greenpeace Russia, an environmental group, raised the alarm about the animals last October. They believe at least four of the whales died while in captivity. Many are known to be in poor health and some have shown signs of hypothermia. In the wild whales swim tens of kilometres every day - and that keeps them warm - but in small pens they get cold.
6-19-19 Floppy eared bunnies look cute but they suffer more health problems
Bunnies with floppy ears might look cuter than normal rabbits but they suffer more health problems, a study has found. “People now need to weigh up whether those cute floppy ears are worth the risk of pain, deafness, and difficulty eating for the rabbit, not to mention the extra vet bills,” says Charlotte Burn at the Royal Veterinary College in the UK, who led the study. The mutations that make some strains of rabbits lop-eared don’t just affect the ears, say Burn. They alter the shape of the skull, making the animals more prone to a variety of problems. At least, that what vets would tell you, says Burn. But no one had actually done a proper study to establish this. So her team went to a rabbit rescue centre and compared 15 lop-eared rabbits with 15 normal ones. They looked for signs of pain or irritation such as ear scratching, examined the rabbits’ ears and mouths, and looked at their medical records. They found the lop-eared rabbits were much more likely to have ear or dental problems that cause pain or difficulty eating, such as narrowed ear canals and misaligned incisors. “The effect size is enormous,” says Burn. In fact, they often had such narrow ear canals that it was difficult to insert an otoscope, says team member Jade Johnson, and some examinations had to be cut short because the animals were clearly in pain. So although the number of animals in the study was small, Burn thinks it very likely that the findings apply to all pet rabbits. She hopes the findings will make people think twice before buying lop-eared rabbits, which now account for over half the rabbits sold in the UK.
6-18-19 Seals consciously reduce blood flow to their blubber before diving
We can now monitor what happens inside diving animals in unprecedented detail thanks to a non-invasive way of recording blood flow and oxygen levels in their brain. The first study with this device shows seals consciously reduce blood flow to their blubber before diving. Almost all mammals, including us, have the so-called dive reflex. It triggers changes in the body, such as reduced blood flow to the skin and a slower heart rate, that reduce oxygen consumption. This reflex was thought to be an automatic response. In humans, for instance, it is triggered by breath holding and cold water on the face. But recent studies suggest that at least some diving mammals have a degree of control. For instance, harbour porpoises slow their hearts more if they are planning to stay under longer. We know little about other changes in the bodies of diving animals because they are very hard to study. So Chris McKnight at the University of St Andrews in the UK and colleagues developed a wearable non-invasive device that uses near-infrared spectroscopy to monitor blood volume and oxygenation. “It’s effectively like a Fitbit,” says McKnight. “It does not penetrate the skin.” When the team attached this device to harbour seals, they found that the peripheral blood vessels of seals started to contract well before they dived – typically around 15 seconds before and sometimes as much as 45 seconds. That means it must be under conscious control, says McKnight. “There’s no other stimulus.” The seals also restored normal blood flow to the blubber several seconds before surfacing, again showing conscious control. The study also revealed that when seals are feeding, they don’t bother to stay at the surface long enough to restore normal blood oxygen levels.
6-18-19 ‘Sneezing’ plants may spread pathogens to their neighbors
Jumping dewdrops might help transmit disease among certain plants such as wheat. Next time you pass a wheat field on a dewy morning, you might want to say “gesundheit.” That’s because some sick plants can “sneeze” — shooting out tiny water droplets laden with pathogens, scientists report June 19 in the Journal of the Royal Society Interface. In wheat plants infected with the fungus Puccinia triticina, coalescing dew droplets flew away from the leaves they were on and carried fungal spores with them, experiments showed. The pathogen, which causes a destructive disease known as leaf rust, might then be able to infect other wheat plants (SN: 9/25/10, p. 22). The flinging effect, which can happen on healthy plants too, is the result of a quirk of fluid dynamics: When two water drops unite, surface tension is released and converted into kinetic energy that can hurl the fluid away. It’s a “surface tension catapult,” says mechanical engineer Jonathan Boreyko of Virginia Tech in Blacksburg. The effect occurs only on extremely water-repellent, or superhydrophobic, surfaces, like the leaves of certain plants, including wheat (SN: 3/1/03, p. 132). The drops can jump a few millimeters — high enough to escape the layer of still air that surrounds each leaf, so that a gentle breeze could carry the water and spores to other plants, Boreyko and colleagues report. The catapulting effect was known to occur on other superhydrophobic surfaces, but this is the first time it’s been suggested that it helps transmit disease. Understanding how leaf rust spreads could be important for controlling it. If “sneezing” turns out to be an important source of transmission, plants could be sprayed with a coating to make them no longer superhydrophobic, for example, Boreyko says.
6-18-19 Worm with eyes in head and bottom found off Shetland
A new species of worm which has eyes in its head and also in its bottom has been discovered in the sea off Scotland. Scientists found the animal during a survey of the West Shetland Shelf Marine Protected Area. Measuring only 4mm (0.2in) in length, it was discovered in a previously unexplored part of the seabed of the large protected area. The worm has been given the scientific name Ampharete oculicirrata. The Joint Nature Conservation Committee (JNCC), Marine Scotland Science and Thomson Environmental Consultants carried out the survey. The worm collected during the survey is now in the collections of National Museums Scotland in Edinburgh. Jessica Taylor, of JNCC, said: "The fact that it was found in relatively shallow depths, relatively close to the Scottish coastline, shows just how much more there is to understand about the creatures that live in our waters." "I'm excited about future JNCC and Marine Scotland surveys and what they may reveal. And it's great that specimens of the new species have been acquired by National Museums Scotland and are available for future studies."
6-18-19 Dogs' eyes evolve to appeal to humans
If a dog has eyes that seem to be telling you something or demanding your attention, it could be evolution's way of manipulating your feelings. Researchers have found that dogs have evolved muscles around their eyes, which allow them to make expressions that particularly appeal to humans. A small facial muscle allows dog eyes to mimic an "infant-like" expression which prompts a "nurturing response". The study says such "puppy eyes" helped domesticated dogs to bond with humans. Previous studies have shown how such canine expressions can appeal to humans, but this research from the UK and US shows there has been an anatomical change around dogs' eyes to make it possible. This allows dogs to create what the researchers call "expressive eyebrows" and to "create the illusion of human-like communication". "When dogs make the movement, it seems to elicit a strong desire in humans to look after them," says the study, co-authored by Dr Juliane Kaminski at the University of Portsmouth. This muscle movement allows dogs' eyes to "appear larger, more infant-like and also resembles a movement humans produce when they are sad". She says that humans would have an "unconscious preference" to protect and breed from dogs with such an appealing trait, giving them an evolutionary advantage and reinforcing this change in subsequent generations. "The evidence is compelling that dogs developed a muscle to raise the inner eyebrow after they were domesticated from wolves," says Dr Kaminski, in a study published in the Proceedings of the National Academy of Sciences of the USA. The findings, from UK and US researchers in anatomy and comparative psychology, show that the facial change has developed over thousands of years of dogs living alongside humans. Previous research has shown that dogs are more likely to use this "puppy eyes" expression when a human is looking at them - suggesting that it is a deliberate behaviour and intended for human consumption. Anatomist and report co-author, Professor Anne Burrows of Duquesne University in the US, says that in evolutionary terms the changes to dogs' facial muscles was "remarkably fast" and could be "directly linked to dogs' enhanced social interaction with humans".
6-17-19 Dogs evolved a special muscle that lets them make puppy dog eyes
Human selection has resulted in dogs evolving more expressive faces. They have a facial muscle for making the “puppy dog eyes” that melt many peoples’ hearts that does not exist in wolves – the ancestors of dogs. This muscle allows dogs to lift up their inner “eyebrow”, which makes their eye look larger. This makes them look more like childlike and also rather sad – the puppy dog eyes look. It really does make dogs more appealing to us. In 2013, Juliane Kaminski at the University of Portsmouth and colleagues videotaped dogs interacting with strangers at a shelter to see what made them more likely to be adopted. “The only thing that seemed to have an effect is this eyebrow movement,” she says. Dogs that made this movement more often were adopted sooner. “It was a surprising result,” says Kaminski, who studies dog-human communication. “That got us really interested.” In 2017, her team showed that dogs make this movement more often when people are looking at them. Now Kaminski and some anatomists have dissected 6 dogs and 4 grey wolves to compare their facial muscles (they used existing specimens – no animals were killed for this study). In dogs, the eyebrow motion is made by a muscle above their eyes, on the inner side nearer the nose, called the levator anguli oculi medialis. Five of the 6 dogs had this muscle. The one exception was a Siberian husky – an ancient breed more closely related to wolves than most dogs. In the wolves – which cannot raise their eyebrows as much – this muscle did not exist. In its place there was a small tendon partially connected to another muscle. So Kaminski thinks this muscle evolved because people favoured dogs that make this expression.
6-15-19 Saving sharks: One woman's mission to protect the hammerhead
Swimming off Cocos Island in the Pacific Ocean, Ilena Zanella had her first close encounter with hammerhead sharks. As social creatures, the sharks gather in their hundreds, and soon she found herself surrounded. Easily spooked by the bubbles coming from her diving equipment, the sharks appeared shy, vulnerable and beautiful. "I saw the vulnerability of this endangered species," she says. "This experience changed my life and I decided to dedicate my work and myself to the protection of hammerheads." Hammerhead sharks are something of a curiosity in the animal kingdom, with their elongated heads and pinprick eyes. Of the nine known species, several are endangered, including the scalloped hammerhead, which is found off the Pacific coast of Costa Rica. Despite threats from overfishing and the shark fin trade, in many areas of the ocean there are no fishing restrictions for hammerheads. The scalloped hammerhead is in decline, according to the International Union for Conservation of Nature - IUCN. Ilena Zanella is co-founder of the non-profit organisation, Misión Tiburón, which is campaigning for better protection for the shark. In Costa Rica, ceviche, the national dish, is commonly made from hammerheads. And Zanella was shocked and saddened to see juveniles being used as fishing bait. "It's an endangered species used as bait," she says. "Actions like that are destroying our oceans and we need to act, we need to do something." Illena Zanella recently won a Whitley Award for her conservation work. She says she will use the award to get better protection for the hammerhead shark. Based on research by her team, the tropical fjord of Golfo Dulce in Costa Rica was declared a shark sanctuary last year, including a large no take zone. The inlet is a crucial nursery ground for the hammerhead.
6-14-19 High-tech vertical farming is on the rise – but is it any greener?
The herbs in your future online supermarket delivery may be grown not in a field in a distant country, but in a shed on the outskirts of a nearby city. This week, UK online supermarket Ocado spent £17 million on vertical farming, an industry that advocates say can produce food in a more environmentally friendly way. But will the investment really allow Ocado to deliver greener food? Ocado has taken a majority stake in Jones Food, which runs Europe’s biggest vertical farm on an industrial estate in Scunthorpe. It has also invested in a joint venture with a further two firms – Priva based in the Netherlands and 80 Acres based in Ohio – involved in vertical farming. Vertical farming sees crops grown indoors under lights, in racks several metres tall. The technology expands production upwards and so requires less land. It also means that crops can be grown closer to where they will be consumed. That partly explains its success in Asia, with commercial vertical farming in Japan dating back more than 15 years. The sector has a much more recent history in Europe, emerging over the past five years. In Scunthorpe, basil and other herbs, watercress and leafy salad are grown in water under LED lights on racking that would collectively cover about 5000 square metres. “There’s always been an energy and employee argument which has probably held back vertical farming over the past decade,” says James Lloyd-Jones of Jones Food. The efficient nature of LEDs has been key to addressing that, along with lower energy lighting that just emits the blue and red wavelengths that plants can use. Fertiliser use – farming’s traditional big energy burden – is “phenomenally reduced”, Lloyd-Jones says. Pesticide use is zero because few insects make it into the indoor environment.
6-14-19 Superweeds are on the brink of becoming resistant to all weedkillers
The most damaging weed in the UK is about to become resistant to the main defence farmers have against it – the weed-killer glyphosate. And the situation is similar in many other countries around the world, with more than 500 weed strains having evolved resistance to at least one herbicide. Many weeds have evolved resistance to several different kinds of herbicides, and some are set to become resistant to all the herbicides used on particular crops. That is bad news for farmers, consumers and wildlife. These superweeds will cause massive crop losses and push up food prices. They will also speed up climate change and harm wildlife as even more land is converted to farmland to make up for the lost crops. “It is not a matter of if but when we are going to be losing chemical control of these weeds,” says Adam Davis of the University of Illinois at Urbana-Champaign. In Europe alone, it is estimated that glyphosate-resistant weeds will cause yields of wheat, barley and oilseed rape to fall around 10 per cent, causing losses of around €2 billion for farmers and pushing up food prices. An additional 2 million hectares of farmland would be needed to compensate, resulting in higher greenhouse gas emissions and a loss of wildlife habitat. The loss of habitat is the single greatest threat to wildlife and biodiversity. The latest threat is a weed called blackgrass. “It can totally infest a field to the extent you can barely see the crop,” says David Comont of Rothamsted Research in the UK. By outcompeting crop plants, it causes yields to plummet. Strains of blackgrass (Alopecurus myosuroides) have already evolved resistance to many herbicides, and some are resistant to several at once. The herbicide glyphosate is often the last line of defence. And now Comont’s tests on blackgrass collected from more than 100 fields in the UK show that it is evolving resistance to glyphosate too.
6-12-19 Koalas burned in wildfires can be now saved but the treatment is gross
With wildfires on the rise, endangered koalas are more threatened than ever, but a new treatment for burned animals offers a ray of hope. We go inside the world's only koala hospital. EVEN for rehab, this is no ordinary hospital. For a start, most of the staff are volunteers. One of them, Sharyn Brown, shows me around the wards – shady, quiet enclosures dotted with gum trees, in which the patients sit. Whiteboards record their progress and requirements. “No melaleuca leaves,” one sign reads. Brown tells me that the hospital employs a “leaf searcher”, who scours the local forests to find foliage for dinner time. “This one,” she explains, pointing to a patient, “came from a part of the state where melaleuca doesn’t grow, so it would make him sick.” Welcome to Port Macquarie Koala Hospital in New South Wales. This unique facility treats around 250 animals each year from across Australia. Some have been hit by cars or attacked by dogs, others have fallen prey to a variety of illnesses, but perhaps the most troubling group are those with serious burns. With wildfires on the increase in the country, burns have become a serious and growing concern for the staff here. Now, however, a new discovery has led to a surprising treatment regime that includes koala faeces, or “poo shakes” as they are affectionately known. “Koalas are pretty chilled and good to work with because they usually let you help them,” says Cheyne Flanagan, clinical director at the hospital. When she started working here 30 years ago, it was just a job, she tells me, but she has grown to love these marsupials. She has also become aware of their idiosyncrasies. “Koalas confound the textbooks. They just don’t react to treatment in the ways you would expect,” she says. “They’re fascinating and puzzling from a clinical viewpoint.”
6-12-19 Bats beat out dogs as the main cause of rabies deaths in the U.S.
In the United States, the landscape of rabies transmission has shifted over the last 80 years. Rabies deaths linked to dog bites and scratches have dropped, and those from wild animals now carry a greater share of the blame. Bats cause roughly 70 percent of deaths in Americans infected with rabies, the U.S. Centers for Disease Control and Prevention says in a report released June 12. In 2015, the CDC noticed that bats were surpassing raccoons in animals testing positive for rabies. The agency also noticed an uptick in the number of mass bat exposures, when 10 or more people are exposed to a possibly rabid bat. This happens most often where bats are found living in homes, dorms or campgrounds. Overseas contact with rabid dogs is second in causing rabies deaths in Americans. People often think infected dogs act aggressively, lunging and barking and trying to attack people. But infected dogs can also be timid and still bite people, says Emily Pieracci, a veterinary epidemiologist at the CDC in Atlanta. “You can’t tell whether an animal has rabies just by looking at it.” People should try to stay away from bats, Pieracci says. A bat that doesn’t flee from humans may be rabid. “A normal, healthy bat will not allow you touch it,” she says. Rabies cases in the United States dropped following a massive campaign to vaccinate dogs starting in the 1950s. But the disease remains active in the wild, infecting coyotes, raccoons, skunks and foxes in addition to bats. Now, rabies control measures by the U.S. Department of Agriculture focus on vaccinating coyotes, foxes and raccoons.
6-11-19 Plant extinction 'bad news for all species'
Almost 600 plant species have been lost from the wild in the last 250 years, according to a comprehensive study. The number is based on actual extinctions rather than estimates, and is twice that of all bird, mammal and amphibian extinctions combined. Scientists say plant extinction is occurring up to 500 times faster than what would be expected naturally. In May, a UN report estimated that one million animal and plant species were threatened with extinction. Researchers say their analysis of all documented plant extinctions in the world shows what lessons can be learned to stop future extinctions. Most people can name a mammal or bird that has become extinct in recent centuries, but few could name an extinct plant, said Dr Aelys Humphreys of Stockholm University. "This study is the first time we have an overview of what plants have already become extinct, where they have disappeared from and how quickly this is happening," she added. The lost plants include the Chile sandalwood, which was exploited for essential oils, the banded trinity plant, which spent much of its life underground, and the pink-flowered St Helena olive tree. The biggest losses are on islands and in the tropics, which are home to highly valued timber trees and tend to be particularly rich in plant diversity. Scientists at the Royal Botanic Gardens, Kew, and Stockholm University found that 571 plant species had disappeared in the last two and a half centuries, a number that is more than twice the number of birds, mammals and amphibians recorded as extinct (a combined total of 217 species). This data suggests plant extinction is happening as much as 500 times faster than what would be expected normally, if humans weren't around. The researchers believe even these numbers underestimate the true levels of ongoing plant extinction.
6-10-19 Humans have driven nearly 600 plant species to extinction since 1750s
Humanity has caused an average of more than two plant species a year to be wiped off the Earth since the middle of the eighteenth century, according to the first comprehensive attempt to chart worldwide plant extinctions. The botany world’s best guess was that fewer than 150 species had gone extinct, but that was based on the Red List of Threatened Species, which is known to cover only a small proportion of all plants. The true number appears to be around four times higher, at 571 plant species being driven to extinction between 1753 and 2018. A Swedish and British team came to the figure after analysing a previously unpublished database kept by Kew Gardens. Species destroyed include the Chile sandalwood (Santalum fernandezianum) which was only found on one group of Pacific islands, and the St Helena olive tree (Nesiota elliptica), which only lived on the island it is named after. The rate of loss is happening as much as 500 times faster than the background rate of extinction for plants, the speed at which they have naturally been lost before humanity’s impact. But even the grim toll of 571 is likely to be lower than the reality, says Aelys Humphreys of Kew Gardens. “We are quite sure this is an underestimate.” That’s because some biodiverse parts of the world are poorly studied, and some plants have been reduced to such low numbers they are considered ‘functionally extinct’. The number of plant extinctions is much greater than the number of modern animal ones. That’s what researchers would expect, given there are more plant species – 300,000-plus – than animals. The geography of the extinctions in plants and animals is strikingly similar though. Island species are inherently vulnerable and have been particularly badly hit, as have species living in regions with a tropical or Mediterranean climate, as they simply have a rich variety of life. Hawaii has seen more losses than anywhere else in the world with 79 extinctions alone, but other hotspots include Brazil, Australia and Madagascar.
6-10-19 Some fungi trade phosphorus with plants like savvy stockbrokers
New details show a fungus shifting its nutrient wares toward more favorable markets. Some stringy fungi are tough negotiators, trading nutrients shrewdly with plants. An advance in tracking the nutrient phosphorus has revealed new details of ancient trading networks between fungi and plants. Some fungal species grow what are called arbuscular mycorrhizal connections underground, reaching intimately into plant roots. These fungi pull phosphorus from the soil and trade it for carbon from a wide range of plants. Marking phosphorus with glowing dots shows the fungi hoarding the nutrient in parts of their elaborate networks of filaments when there’s a glut of it and plants wouldn’t be likely to trade much carbon. Phosphorus also gets shipped over the fungal networks to areas where it’s scarce and thus more valuable to trade, an international research team reports June 6 in Current Biology. These fungal-plant trades have been frustrating to study as biological markets because, until now, researchers could see snapshots, but not details, of the negotiations, says study coauthor Toby Kiers, an evolutionary biologist at Vrije Universiteit Amsterdam. It was “like a really good poker game” where the lights go out between dealing and winning, she says. For a better view, the researchers devised a way to watch the process in action by tagging phosphorus with nanoparticles called quantum dots that glow red or blue in ultraviolet light. Arbuscular mycorrhizal fungi have no ability to capture carbon themselves, though they need it to live. Instead, they have traded with plants for the resource for some 450 million years (SN: 9/10/11, p. 15). Today, the fungi can connect with at least 70 percent of all plant species, including most crops. Unlike other nutrient-trading fungi that sheath a plant root, these fungi work their way inside plant cells and grow “beautiful treelike structures” with plenty of surface area that can help with swapping sustenance, Kiers says.
6-10-19 Carnivorous pitcher plants are regularly eating vertebrate animals
The pitcher plants in Canada don’t just eat insects – they also feast on amphibians. A survey late last summer revealed that a fifth of the pitchers in one bog had caught at least one juvenile salamander. “That was a WTF moment,” says Alex Smith of the University of Guelph. Pitcher plants are famous for feeding on insects. But last year, Smith found a young yellow spotted salamander trapped in one of the pitchers of the purple pitcher plant (Sarracenia purpurea purpurea) while doing field work with undergraduates at Algonquin Provincial Park in Ontario. He mentioned it to Patrick Moldowan of the University of Toronto and other researchers. They started looking out for trapped salamanders and soon made further discoveries. In August and September, Moldowan did a survey, checking the contents of more than 100 plants on several occasions. In late August and mid-September – the time when thousands of newly metamorphosed salamanders emerge en masse from a nearby lake – he found a fifth of plants had caught at least one salamander. It’s not clear whether this site is exceptional. But it’s a well studied site, says Smith, so it might just be that no one has realised how common this before. The juvenile salamanders, which are around 5 centimetres long, might be falling in by accident, or entering to feed on trapped insects or to seek shelter. For those salamanders that cannot escape, it’s a slow death. It takes between three and 19 days for them to die. What kills them is not known – they might starve to death, overheat as the pitchers warm in the sun or be killed by something in the fluid. Overall, the team estimates that up to 5 per cent of the emerging salamanders may be killed by the pitchers – making the pitchers a major predator.
6-8-19 Lizards' grip became ten times stronger after hurricane Maria
Lizards on the Caribbean island of Dominica appear to have suddenly developed a super strong grip. Measurements before and after a hurricane hit the island reveal the lizards’ grip has become ten times stronger – although it is not clear why. In September 2017, Category 5 strength hurricane Maria devastated Dominica and may have drastically altered some of the nation’s wildlife. Claire Dufour at Harvard University and her colleagues were in Dominica in 2016, studying the coexistence of two types of lizard: invasive crested anoles (Anolis cristatellus) and native anoles (Anolis oculatus). The team captured the lizards, recording the two species’ body size and toe features, as well as their clinging ability by measuring the force required to drag their feet along a surface. After the hurricane, Dufour and her colleagues wanted to see if it had affected any of these characteristics, so in 2018, they returned to Dominica to re-sample the anoles. While body size and toe pad shape didn’t change, both anole species had dramatically stronger grips following hurricane Maria, about ten times stronger than their 2016 counterparts. One possibility is that anoles with stickier feet fared better in the hurricane’s violent winds, meaning the remaining population grew from a group of the strongest clingers. “This study shows that hurricanes may be a previously overlooked driver of performance in Anolis lizards,” says Dufour. “This is pretty unique.” Last year, Dufour’s colleagues published findings that showed a different Caribbean hurricane spurring changes in toe pad shape in anoles, but this is the first study showing the lizards increasing their grip after a storm.
6-7-19 Overbearing bonobo moms
Mothers have been known to nag their grown children to produce grandkids, but bonobo moms take the pressure to a whole new level. These moms are so determined to become grandmothers that they will stand by when their sons mate with a female and fight off any other males that try to disrupt the lovemaking. These overbearing ape moms also run interference, breaking up liaisons between females and males that aren’t their sons. Occasionally, mother and son even team up to attack the latter’s sexual rivals. This forceful maternal behavior is well documented, and a new study has concluded for the first time that it actually helps the sons thrive, reports DiscoverMagazine.com. Researchers found that wild male bonobos in Congo whose mothers were still with them fathered three times more offspring than bonobos whose mothers had died or left the group. Lead author Martin Surbeck, from the Max Planck Institute in Leipzig, Germany, says bonobo moms likely act as they do to “increase their reproductive success without having more offspring themselves.”
6-7-19 Some trees can change sex and are more likely to die when female
Being female can be tough, even for trees. A study of the life cycle of striped maples – which can change sex from season to season – has revealed that healthy trees are more likely to be male, and most trees die while in the female flowering state. “We had a suspicion they were changing sex, which is relatively rare among plants,” says Jennifer Blake-Mahmud of Princeton University. Between 2014 and 2017, she tracked the life cycles of striped maples (Acer pensylvanicum) in state forests and park lands in New Jersey. She visited 457 striped maples each spring, measuring their diameter, the condition of their leaves and branches, and recording whether they had female or male flowers. “It was just me and my trusty field dog. I would go out and count all the flowers and then determine the sex of the different trees,” she says. She found that 54 per cent of the trees switched sex during the 4-year period, and a quarter of those switched sex at least twice. A model based on the data she collected showed that, contrary to previous theories, healthy trees were more likely to be male and the size of a tree doesn’t influence its sex. She found that the growth rate of trees that remained female for multiple years deteriorated, and 75 per cent of the dead trees had produced female flowers just before they died. “It’s remarkable. When I see a tree that’s dead and I look back in my data sheet, it was almost always female the year before,” she says. It’s not clear why this is the case. It could be that females need more nutrients because they produce seeds, and that’s so taxing the trees die, says Blake-Mahmud. But it could also be that when a tree is dying, it switches to female as a last effort to create offspring and pass genes on to the next generation.
6-7-19 Blue belt zones to protect minke whales
Special protections are planned for minke whales and basking sharks in their feeding grounds around Scotland. A consultation has been launched on creating four new Marine Protected Areas (MPAs) covering 5,000 square miles of sea. The Scottish government said the proposals were a world first and would also protect Risso's dolphins and a wide range of other biodiversity. The Whale and Dolphin Conservation charity said it was "delighted." The proposed sites are at the southern trench in the outer Moray Firth, north east Lewis, the Sea of the Hebrides and Shiant East Bank. MPAs are sometimes referred to as the "blue belt". There are areas of sea in which species and habitats benefit from special protections such as prohibiting fishing or dredging. The management of each zone differs depending on the requirements of marine life and local people, including fishermen. The first modern day MPAs were introduced following the Marine (Scotland) Act of 2010. There are now 231 - including historic ones - covering 22% of the seas around Scotland. The Scottish government's aim is that by the end of 2020 Scotland's MPA network will be complete. Details of the specific restrictions to accompany the proposed four new MPAs will be finalised at a later stage. Rural Affairs minister Mairi Gougeon said the new MPAs would put further protections in place for some of Scotland's "iconic" species and habitats. Ms Gougeon said Scotland's seas accounted for 61% of the UK's waters and were internationally recognised as being important for whales, dolphins and basking sharks. Alison Rose, manager of WDC's Scottish Dolphin Centre at Spey Bay, said: "We can use Marine Protected Areas as a tool to control some of the activities that might affect the minke whales. So, things like noise pollution, possibly fishing activity. "The southern trench is a very deep part of the sea and it's a nursery ground for lots of juvenile fish; so, things like sandeels, sprat and herring. All the kind of fish that minke whales like to eat. "This population of minke whales travel here every summer, resting up and feeding on these juvenile fish."
6-6-19 Cat declawing: Should it be banned, and why does it happen in the US?
New York might become the first US state to ban cat declawing. In a bipartisan move on Tuesday, lawmakers voted to make the procedure illegal, except where it is medically necessary for the cat. The governor, Andrew Cuomo, needs to review and sign the bill before it becomes law. Critics say cat declawing - which involves cutting off a segment of the bone attached to the claw - is "barbaric and inhumane". But the New York Veterinary Medical Society has argued that it should still be an option when otherwise the cat might be abandoned or put down. Cat declawing is already illegal in many countries in Europe, including the UK, as well as Brazil, Israel, Australia and New Zealand. Why is it so controversial - and why does it still happen in the US? The most frequent type of declawing is called an onychectomy - it involves cutting the bones the claws grow from with a scalpel or laser. Critics compare this to cutting off someone's toes or fingers at their top joint, and say declawing can affect a cat's balance. There are some cases where the surgery is medically necessary, "if there's a bad infection in the nail bed, or a tumour," says Dr Sarah Endersby, veterinary development manager at International Cat Care, a charity. However, she adds, many people declaw cats to stop them from scratching the furniture, which she calls "essentially an act of mutilation done to modify the cat for our benefit". Attitudes differ widely across the Atlantic. While many European countries signed a treaty forbidding the practice in the early 1990s, an AP poll in 2011 found that 55% of US cat owners said it was OK to declaw their cats. Some studies suggest that between 20% and 25% of pet cats in the US have been declawed. By contrast, "declawing was always rare" in the UK, even before it was outlawed in 2006, says Prof Danielle Gunn-Moore, a vet and chair of feline medicine at the University of Edinburgh.
6-6-19 Worms lure two new species of hopping rats out of obscurity
The rodents exemplify the rich biodiversity at risk of being lost in the Philippines. Two newfound species of shrew-rat have joined a lengthy list of endemic mammals on Luzon, the largest island in the Philippine archipelago and a hotbed of biodiversity. Researchers made their discovery thanks to wriggling worms and a stroke of luck, and hope the finding might help sway legislators to protect the vulnerable ecosystem before it’s too late (SN: 6/8/19, p. 5). The new species, Rhynchomys labo and R. migan, sport plush fur, pointed snouts and kangaroo-like feet, researchers report June 6 in the Journal of Mammalogy. The distinctive rodents once eluded field scientists, snubbing the standard rodent bait of roasted coconut slathered in peanut butter. It wasn’t until unwary shrew-rats stumbled into a trap that scientists learned that the animals prefer a more succulent snack: earthworms. “We baited our traps with earthworms, and the next day we had a couple dozen of these things,” says Eric Rickart, a curator of the Natural History Museum of Utah at the University of Utah in Salt Lake City. Rickart, along with Lawrence Heaney of the Field Museum in Chicago and many other collaborators, applied this knowledge at field sites across Luzon. In the late 2000s, expeditions to Mount Labo and Mount Mingan revealed two unknown shrew-rat populations, found above 1,250 meters and 1,450 meters, respectively. After comparing the animals with four known Rhynchomys species, the researchers confirmed their discovery and named the new species after their mountainous habitats. The scientists had expected to find unrecognized species hiding out in the towering mountains. Mammalian diversity abounds on mountain slopes in part because the peaks isolate populations of related animals. Shrew-rats and their rodent relatives all likely evolved from a single ancestor, whose population scattered upon arriving on Luzon, Rickart says. Then each group adapted to the particular conditions found on different mountains over time, evolving into separate species.
6-6-19 Plan to remove hen harrier eggs and raise them in captivity criticised
England’s nature regulator is pushing ahead with a controversial plan to take hen harrier eggs from the wild and rear the birds in captivity. Hen harriers are struggling to survive in the UK because they are being killed illegally. A recent satellite-tracking study found the birds of prey are more likely to disappear over grouse moors, which are managed for game shooting. Hen harriers do eat grouse, but these are thought to form only a small part of their diet. Today, Natural England said that the conditions had now been met for a license issued eighteen months ago that allows the removal of hen harrier eggs, which would normally be illegal. The license is heavily redacted, and we do not know who will be removing the eggs or where they will be taken to for rearing in captivity. It is understood that the eggs will be taken from a site in the north of England. The deadline for this removal is January 2020. The move to implement a “brood management” plan has been condemned by conservationists. Mark Avery, a former director of the Royal Society for the Protection of Birds who launched a failed legal challenge against the license last year, says: “I think it’s just wrong. If you are a hen harrier you wouldn’t make this management plan. The only people in favour of it are grouse moor owners.” The plan is a distraction from the real issue of tackling illegal persecution, he adds. “Even if this crackpot scheme resulted in a few more hen harriers fledging [and] getting to the flying stage, if they are all going to be shot a few weeks later, it is utterly pointless.” The RPSB has expressed disappointment, saying brood management was the “wrong tool” and illegal persecution must end. But the Moorland Association, which represents grouse moor estates, welcomed the scheme and said there was a “genuine will” among landowners and managers for it to succeed.
6-5-19 AI camera worn by gulls captures video highlights of their lives
Attaching cameras to animals has allowed wildlife film-makers and biologists to capture some extraordinary footage, from bird’s eye views of eagles soaring in the skies to sperm whales hunting in the depths. Now artificial intelligence could help us capture a lot more revealing footage. A team in Japan has created a low-power AI system for recognising when animals are doing something interesting and switching on high-power systems like videos only during those moments. That means the devices can keep working for far longer before running out of power. Takuya Maekawa of Osaka University worked with biologists using biologgers — devices equipped with a camera, accelerometer and GPS — to study black-tailed gulls from a breeding colony located on Kabushima Island. The devices weigh just 27 grams and cannot record video for long. Maekawa trained an AI to recognise when the birds were feeding by analysing the movements recorded by the low-power accelerometer. The AI checks whether the bird is flying and whether the patterns of movement resemble those associated with feeding, based on previous recordings. The team then put the system to the test. Of 27 videos taken without the AI, none showed feeding. In fact, the birds were stationary in 24 of them. By contrast, of 185 taken with the AI, the birds appearing to be foraging in 58 of the videos, and were stationary in just 41. That’s a success rate of around 30 per cent, which is impressive for an algorithm that can run on the tiny processing unit inside the biologgers. This first small study even recorded some previously unknown behaviour, with several videos showing the black-tailed gulls catching insects out at sea. “Feeding on insects over the sea has not been observed before,” says Maekawa.
6-5-19 Dragonfish have 'invisible' teeth to help them sneak up on their prey
Deep-sea fish have evolved transparent teeth which, along with their black bodies, make them invisible to prey. While dragonfish are only the size of a pencil, they are fearsome predators at the top of the food chain. Their thin, eel-like bodies support a huge black mouth filled with razor-sharp teeth, that can widen to swallow prey half their size. Marc Meyers at the University of California San Diego and his colleagues have discovered what makes these teeth almost entirely transparent. Using an electron microscope, they found that the teeth contain grain-sized nanocrystals spread throughout the enamel. Materials are transparent when light can pass through them with little scattering, and because these structures in the surface of the teeth are so small, they don’t scatter or reflect much light. Dragonfish teeth are made from an outer enamel-like layer and an inner layer made of dentin. They are sharper than piranha teeth and probably as hard as a great white shark’s teeth, says Meyers. Having thinner teeth than many other predatory fish also helps reduce their visibility, he says. Their dark-skinned bodies already help dragonfish camouflage into the inky blackness of the deep ocean, and they use a light-emitting lure near their mouths to entice prey toward them. But the evolution of transparent teeth means that this bioluminescence doesn’t reflect onto their teeth and blow their cover. This means the mouth would be invisible to prey right until the moment it was caught. “I would see a mysterious light source toward which I would be attracted,” Meyers says describing the prey’s final moments. “Suddenly, I would be trapped and pierced.”
6-4-19 'Fear' of killer shrimp may threaten rivers
An invasive "killer shrimp" that has reached UK rivers could be altering the behaviour of other species through fear alone. A study shows that the mere presence of the "alien" crustacean can make other species less effective at the tasks they perform in aquatic ecosystems. The invasive animal preys on an array of species, including other shrimp, damsel flies and water boatmen. It has been linked to local extinctions in other countries. The new research was carried out by independent consultant Calum MacNeil and University of Plymouth professor of animal behaviour Mark Briffa. It shows that the mere presence of the predator can prevent other species from carrying out core ecosystem functions such as shredding fallen leaf litter into smaller particles so that it can be consumed by other species. The prey species expend more energy in simply avoiding the "killer shrimp" - or to use its formal name, Dikerogammarus villosus - rather than focusing on behaviours they would exhibit in its absence. For the study, one of three different shrimp species belonging to the genus Gammarus (all commonly found in European rivers) were placed inside a tank. In half of the tanks, a sample of D. villosus was also placed inside a cage. The behaviour of the Gammarus shrimp was then assessed over the space of several days, with researchers measuring to what extent they shredded leaves as they would be expected to. The results showed that after four days, each Gammarus species showed lower shredding efficiency in the presence of the caged "killer shrimp" compared to those in tanks where it was absent. "This study demonstrates an unappreciated and indirect impact of a biological invasion by a voracious predator," said Dr MacNeil. "It shows that the mere presence of an invader can influence resident prey behaviour, in this case the feeding efficiency of naïve residents."
6-4-19 How one fern hoards toxic arsenic in its fronds and doesn’t die
Key proteins keep the heavy metal from wreaking havoc on the way to its cellular jail cell. The Chinese brake fern looks unassuming. But Pteris vittata has a superpower: It sucks up arsenic, tucks the toxic metal away in its fronds and lives to tell the tale. No other plants or animals are known to match its ability to hoard the heavy metal. Now researchers have identified three genes essential to how the fern accumulates arsenic, according to a study in the May 20 Current Biology. The fern shuttles the heavy metal, often found as arsenate in soil, from the plant’s roots to its shoots. There, the three genes make proteins that help corral arsenate as it moves through the plant’s cells and into a cellular compartment called a vacuole, where the arsenic is sequestered, the team found. One protein, GAPC1, gloms onto the arsenate, possibly keeping it from doing damage during its journey. Another, OCT4, appears to help arsenate cross membranes, possibly into a structure where a third protein, GSTF1, transforms it into arsenite, the form stored by the plant. Tinkering with the genes caused the plants to die when exposed to arsenic, say Jody Banks, a botanist at Purdue University in West Lafayette, Ind., and her colleagues. These ferns are already being used to draw arsenic out of soil in some contaminated areas. It “takes a long time, but it’s really cheap,” compared with the millions of dollars it can cost to dig out contaminated dirt and clean it, Banks says. In one previous study, the ferns sucked up about half of the arsenic in heavily contaminated soil in five years.
6-3-19 Elephants can judge the quantity of hidden food just by using smell
When it comes to quantities, an elephant’s nose knows. Elephants can use their sense of smell to detect the largest amount of food among two samples, even when the food is hidden from sight. “For some reason every elephant I’ve ever worked with in Thailand loves sunflower seeds,” says Joshua Plotnik at the City University of New York. He and his colleagues worked with six Asian elephants in Thailand, testing their ability to discern between different amounts of seeds. Two buckets with locked lids were set on a long table, each with different quantities of seeds ranging from 4 to 24 grams. Each trial used one of 11 ratios of seeds in the buckets – for example 1 to 2, or 3 to 5 – and each elephant completed 10 trials. Once the elephants sniffed the buckets, they were unlocked and the animals chose one to eat from. The elephants chose the greater quantity 69 per cent of the time overall. As the difference between the seed quantities increased, the elephants selected the larger amount more often. There was no difference in their success rate when the ratios were the same but the amounts changed – say, they were given either 4 grams versus 8 grams, or 12 grams versus 24 grams. To eliminate the chance that the elephants were using cues from humans, the team ran a double-blind test where the experimenters didn’t know which bucket had the most seeds. They also accounted for residual odour in the buckets from previous tests and used a metal bucket to account for any smells that may be better transmitted by plastic. In all cases, the elephants were still able to discern the larger quantity. “After that, I thought maybe they are just smelling the larger quantity better because the seeds reach higher in the bucket,” says Plotnik. “But we raised the seeds up in the bucket so they were at the same level, and the elephants could still tell the difference.”