News and Notes About Science
Posted May 14, 2018 7:00 p.m. EDT
Research Suggests That the Elephant Walk May Also Be a Kind of Talk
With a trunk that produces 110-decibel blasts that can be heard for miles, elephants are well-equipped for long-distance communication. But it turns out they may be letting their feet do some of the talking, too.
Using tools designed for detecting earthquakes, researchers found that different elephant activities — walking, running, snorting, grunting — create distinct “seismic signatures” in the ground. In some cases, according to a study published recently in the journal Current Biology, these vibrations travel farther through the ground than they could through the air, giving the animals a variety of powerful methods for long-distance communication.
“It’s not surprising that walking affects their vibrations, but they’re so big that their snorts and grunts also generate very low-frequency vibrations,” said Beth Mortimer, a biologist at both the University of Oxford and the University of Bristol and lead author of the study. “And by monitoring the vibrations through the ground, we could determine what the elephants were doing.”
Earlier studies have shown that elephants may be monitoring ground vibrations through their bodies, a trait more commonly associated with small creatures such as scorpions and insects. For example, elephants have been observed fleeing for higher ground in the moments before distant tsunamis, and a mother elephant who feels threatened will stomp on the ground to warn others away. By suggesting that elephants not only cause distinct vibrations with different activities, but can perceive the difference from great distances, the research expands the possibilities of what the animals may be communicating.
It also presents a new opportunity for researchers and conservationists looking to surveil the animals at a distance, a tactic that could be useful for saving a species that is threatened by poachers. “What we’ve shown is that we can basically use this as a remote monitoring strategy,” Mortimer said. Despite international efforts to ban the trade of ivory dating back decades, tens of thousands of African elephants continue to be killed for their tusks every year.
— DOUGLAS QUENQUA
Frog-Killing Fungus Has Korean Origins
In the 1970s and 1980s frogs and other amphibians seemed to be disappearing overnight. By 1999, researchers had determined the culprit was a deadly disease caused by chytrid fungus which infected the animals with tiny, swimming spores.
Today this disease, called Chytridiomycosis, is thought to be one of the deadliest pathogens on the planet. It infects hundreds of species of amphibians and is thought to have wiped out a third of all frog species. These animals are important contributors to biodiversity, insect and disease control and may even be sources of new types of medicine.
Now, an international group of scientists has compared the genomes of 177 samples of the deadly fungus from six continents. They determined that the pathogen most likely arose on the Korean Peninsula 50 to 100 years ago and spread through global trade.
Their research, published recently in the journal Science, reiterates that the pathogen comes in many different strains, some more virulent than others. It suggests that new variations of the fungus can still develop and spread disease without proper protections.
Previously, researchers were limited by the scrappy bits of the fungus’ DNA they could obtain by smearing a cotton swab across the skin of a frog or a salamander.
But by sequencing the full genomes of samples of the fungus, also called Batrachochytrium dendrobatidis or Bd, from all over the world, the team, led by Simon O’Hanlon and Matthew Fisher, infectious disease epidemiologists at Imperial College London, found that samples shared the most genetic information with a group obtained from frogs that live on the Korean Peninsula, suggesting this was where it had originated.
They also discovered that this Korean lineage contained strains that were more genetically diverse than any others — and because it infected animals but did not kill them, it likely had been living with amphibians, who learned to tolerate or defend against it, for some time.
The researchers think the virulent, global strain emerged within the past century coinciding with rapid development in global technology, commerce and trade. During this time, animals stowed away in equipment or produce or they were traded directly as scientific or medical specimens, food and pets. These amphibians likely harbored the fungus, allowing it to become more virulent and spread to others not adapted to it.
— JOANNA KLEIN
A Feathered Terror Is Slaughtering Bats
The greater noctule is the largest bat in Europe. It is listed as “vulnerable” on the threatened species list, but for many years these winged mammals found shelter in the hollows of trees at María Luisa Park in Seville, Spain.
Then a few years ago, they started to turn up dead.
The corpses were savaged, with holes torn in their wings, scientists who study the colony discovered. Many of them were nursing pups; one corpse was a pregnant female.
The culprit turned out to be another park inhabitant: beautiful, invasive rose-ringed parakeets who also make their homes in tree hollows.
Now there are thousands of birds, and they are pushing the bats out of their holes, killing some, and taking over the trees where noctules once lived.
In a new paper in Royal Society Open Science, the researchers provide evidence that unless something is done about the parakeets, the park’s group of noctules, one of the largest known breeding colonies in Europe, is likely to be obliterated in the near future. The discovery also offers a real-time view of what happens when an invasive organism finds a new niche and displaces a native species.
In a cage, or its own habitat in Asia and Africa, the rose-ringed parakeet is a charming, sociable bird. Martina Carrete, a conservation biologist who is an author of the new paper, said the parakeets are believed to have first appeared in the park after about 10 of them were confiscated from a pet shop and released around 1990.
“At this time, nobody expected that they could become an aggressive invasive species,” she said.
Today, the number of trees that noctules live in has dropped by 81 percent since the researchers first began keeping track, with the parakeets taking over the bats’ old homes. The bat population appears to have roughly halved since the work began, bringing their numbers down to about 250.
The scientists helped the city government come up with an eradication plan to get rid of the parakeets in 2016, but at the last moment, officials canceled the plans. The parakeets are popular, and citizens argued there must be some other way besides killing them — perhaps artificial nest boxes for the bats. However, the bats do not take to such nests well.
— VERONIQUE GREENWOOD
Alan Turing’s Insights Just Keep On Giving
Many have heard of Alan Turing, the mathematician and logician who invented modern computing in 1935.
But few have heard of Turing, the naturalist who explained patterns in nature with math.
Most recently, in a paper published recently in Science, chemical engineers in China used pattern generation described by Turing to explain a more efficient process for water desalination, which is increasingly being used to provide freshwater for drinking and irrigation in arid places.
Turing’s 1952 paper did not explicitly address the filtering of saltwater through membranes to produce freshwater. Instead, he used chemistry to explain how undifferentiated balls of cells generated form in organisms.
It’s unclear why this interested the early computer scientist, but Turing had told a friend that he wanted to defeat Argument From Design — the idea that for complex patterns to exist in nature, something supernatural, like God, had to create them.
“He certainly was no militant atheist,” said Jonathan Swinton, a computational biologist and visiting professor at the University of Oxford who has researched Turing’s later work and life. “He just thought mathematics was very powerful, and you could use it to explain lots and lots of things — and you should try.”
In Turing’s model, two chemicals he called morphogens interacted on a blank arena.
“Suppose you’ve got two of these, and one will make the skin of an animal go black and the skin of the animal go white,” Swinton explained. “If you just mix these things in an arena, what you get is a gray animal.”
But if something caused one chemical to diffuse, or spread, faster than the other, then each chemical could concentrate in evenly spaced localized spots, together forming black and white spots or stripes.
This is known as a “Turing instability,” and the Chinese researchers who published the new paper determined that it could explain the way shapes emerged in salt-filtering membranes.
By creating three-dimensional Turing patterns like bubbles and tubes in membranes, researchers increased their permeability, creating filters that could better separate salt from water than traditional ones — which means less energy and lower cost if used for large-scale desalination operations.
— JOANNA KLEIN
An Asteroid Strayed From Its Companions
At first the astronomers thought it was a mistake. They had found a carbon-covered asteroid floating among countless icy bodies far away in our solar system. The newly discovered space rock, which they named 2004 EW95, was something the scientists would have expected to have seen in the asteroid belt between Mars and Jupiter. Instead, it was dancing near Neptune.
Their finding suggests that 2004 EW95 is the first of a new class of space objects lurking in the outer solar system, in a vast, frigid region known as the Kuiper belt that still contains many mysteries. The researchers believe the asteroid sling-shotted from the inner solar system 4.5 billion years ago, and it may provide insight into the early formation of our planets.
Using the European Southern Observatory’s Very Large Telescope, Tom Seccull, a doctoral student at Queen’s University Belfast in Northern Ireland, and his colleagues examined light signatures from the icy surfaces of Kuiper belt objects. They noticed something strange about one object that measured nearly 190 miles long and was 2.5 billion miles from Earth. Their analysis showed that this object did not share the same frigid past as the ice balls drifting nearby.
“When we first looked at this, we thought it was wrong,” said Seccull, lead author of the paper published recently in The Astrophysical Journal Letters. “The rock had been altered by the presence of liquid water.”
That most likely meant the asteroid once resided in a hotter environment much closer to the sun. The team also found that the asteroid’s chemistry was dominated by compounds called ferric oxides and phyllosilicates, which had never been seen before on Kuiper belt objects.
These pieces of evidence led the team to conclude that 2004 EW95 was formed in the inner solar system, and had most likely been hurled to the outer solar system as the giant gas planets, Jupiter and Saturn, migrated away from the sun.
By finding 2004 EW95, astronomers have stronger evidence that objects near the sun, like asteroids and gas giants, moved into the outer solar system billions of years ago.
“We are lucky to be here, because the gas giants didn’t destroy the inner solar system,” said Thomas Puzia, an astronomer at Pontificia Universidad Católica de Chile and an author of the paper. “Understanding that — why it happened and how early it happened — tells us more about our birthplace.”
— NICHOLAS ST. FLEUR