Lights at night trick wild wallabies into breeding late

Artificial lighting at night delays wild tammar wallaby breeding, potentially pushing the nursing marsupial moms out of sync with their peak season for food.

Tammar wallabies (Macropus eugenii) that live on the well-lit landscape of Australia’s largest naval base muddle the timing of their natural breeding season. Births peak in February — a month later on average than normal — then dip only to surge again in April, says zoologist Kylie Robert of La Trobe University in Melbourne, Australia. By the time these late-arriving joeys have grown to their most demanding stage some 250 days in the pouch later, the best grazing greened by winter rains is fading. Nursing moms and their joeys once got through this season thanks to all the irrigated lawns on the base. New irrigation rules, however, now leave the wallabies facing food shortages.

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‘Protocells’ show ability to reproduce

Man-made balls of genetic material and membranes can pull off a decent impression of primitive cells. 

These squishy spheres known as “protocells” can accept chemical deliveries to sustain a division process that mimics that of living cells, researchers in Japan report September 29 in Nature Communications. These cell-like creations may be a step toward making future protocells that can imitate evolution, the scientists say.

The results offer clues to how living cells developed their ability to reproduce, says study coauthor Tadashi Sugawara, a physical organic chemist at Kanagawa University in Japan. Like the cells within plants and animals, these protocells have four stages in their division process, Sugawara says. The real living cells and the protocells both have a replication stage and division stage. But instead of two growth phases, these protocells have an “ingestion” stage, in which they take in substances from their surroundings, and a “maturity” stage.

The protocells, composed of thin membranes wrapped around DNA and proteins, can expand and divide when provided with a membrane-building molecule. But new protocells quickly run out of other biochemical ingredients needed to continue reproducing. So the researchers designed membrane-wrapped delivery vessels that provide daughter protocells with additional biological building blocks. With these ingredients, the protocells can continue dividing for a third generation.

These protocells appear to require a complex design to work properly, says evolutionary biologist David Baum of the University of Wisconsin–Madison. Plus, some scientists believe cell precursors like these may not have been the first living things to undergo evolution, he says. Chemical oozes may have been able to cooperate with each other and grow more sophisticated over time, before a cell’s ancestors developed, he says.

Baum notes that the protocells in the study aren’t self-sustaining, as the researchers must replenish the system with essential chemical ingredients. The protocells also depend on fluctuations in heat and acidity to copy their genetic material and accept chemical deliveries, which makes them too artificial to be sustainable, Sugawara says. But he notes that hot, acidic environments like those around hydrothermal vents could have driven similar genetic processes in nature.

Good imitators of early cells could help scientists understand how real cells evolved, he adds. “If we could make many instances where we could get evolving protocells, and we could see what you need, that would really help us understand how that could have arisen naturally.” 

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Some bats chug nectar with conveyor belt tongues

A subset of bats that eat off the nectar menu sip from flowers using specialized tongues that pump liquid up to their mouths, researchers report September 25 in Science Advances.

Nectar-feeding bat tongues come in two varieties: hairy and groovy. By analyzing high-speed videos of bats feeding, ecologists found that the two anatomies translate to vastly different feeding behaviors. Most nectar-feeding bats have tiny hairs called papillae at the end of their tongues that allow the bats to lap up nectar as cats do milk.

But grooved-tongued bats (Lonchophylla robusta in this study) actually pump nectar up their tongue without breaking contact with the liquid — unlike any other mammal but strangely like a conveyor belt. Capillary action and tongue distortion probably push nectar up the tongue, the researchers write. 

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Math describes sheep herd fluctuations

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There’s something in the way sheep move.

In a herd, Merino sheep follow a predictable pattern of spreading out and clustering together. Now scientists have developed equations that can describe those movements. The sheep’s choreography may allow them to balance their needs for food and protection, researchers report September 28 in the Proceedings of the National Academy of Sciences.

“This is the first quantitative study of this kind of behavior,”says study coauthor Francesco Ginelli, a collective animal behavior and active-matter researcher at the University of Aberdeen in Scotland. Ginelli and his colleagues developed equations that describe how the sheep move and respond to their neighbors. The results suggest that a herd of sheep may exist in a delicate balance, close to a “tipping point” between dispersing and huddling together, says Andrea Cavagna, a statistical physicist at the Institute for Complex Systems of the National Research Council in Rome. 

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An observed group of 100 ewes slowly drifted apart while grazing, only to suddenly clump back together roughly every 15 minutes, the researchers report. The behavior occurred unprompted, without any nearby predator to spook the herd. Sheep toward the outside of the herd seemed to initiate each woolly avalanche by running toward the center of the group, tailed by their neighbors.

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Sheep follow fluctuating patterns of spreading out and clumping together. Sheep on the outskirts of a herd initiate a clustering response by running towards the rest of the group.F. Ginelli et al/PNAS 2015

Ginelli and his coauthors believe that a herd’s oscillations balance two ovine interests: maximizing grazing space, and having safety in numbers should a predator approach. “The interpretation —balancing these two things — it’s simple and elegant,” Cavagna says. The mathematical model in the study supports this proposed behavior, he says.

Future experiments will examine larger groups of sheep, and may explore what happens if a single sheep is actually spooked by something, Ginelli says. He believes these results may help scientists understand the behavior of other groups of animals — for example, humans fleeing a burning building. 

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Salt streaks sign of present-day water flows on Mars

Liquid water might not be a distant memory on Mars. New data suggest water flows on the Red Planet even today. Seasonal dark streaks etched onto some slopes are coated with salts that need liquid water to form, researchers report online September 28 in Nature Geoscience. The Mars Reconnaissance Orbiter recorded spectra showing hydrated salts at four locations on Mars.

The salty trails appear annually, showing up only in warm seasons. Rising temperatures probably drive water to the surface, though whether the source is buried ice, local aquifers or something else is unclear.

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67P reveals recipe for a comet

To make one oddly shaped comet, take two smaller comets and squish them together. That probably explains why comet 67P/Churyumov-Gerasimenko looks like a rubber duck, a new study reports.

Since the Rosetta spacecraft’s arrival last August (SN: 9/6/14, p. 8), researchers have debated whether 67P was a comet that lost some weight around its waistline or two comets that got a little too attached to one another. Layers and terraces on cliffs gave away 67P’s coupling. Mismatched layers between the head and body imply that the two lobes formed independently and later fused together, Matteo Massironi, a geologist at the University of Padua in Italy, and colleagues report online September 28 in Nature.

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Mysterious circles appear, grow on comet

A comet is growing its own version of crop circles. Over the course of a month, five expanding disklike depressions appeared on the surface of 67P/Churyumov-Gerasimenko in images taken by the Rosetta spacecraft, which has been orbiting 67P since August 2014 (SN: 9/6/14, p. 8).

The first roundish feature showed up on June 3 and was joined by a second 10 days later. Within a month, the first spot had grown to 220 meters across and 5 meters deep, and it had run into its neighbor. Three more spots appeared in early July, flanking the original two, researchers report online September 15 in Astronomy & Astrophysics.

The spots form around weak points in the surface, where sunlight can easily turn buried ice to vapor. That vapor in turn erodes the surrounding smooth plain — though the pits are growing too fast for sublimation alone to be their cause. Loosely bound dust or heat released by ice as it transforms from a disarray of water molecules into orderly crystals might help the spots along. Unlike with crop circles, bored pranksters are probably off the hook.

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Life in the polar ocean is surprisingly active in the dark winter

Scientists have long thought that in the supercold, perpetually dark, polar winter, life pretty much shuts down. With no sunlight, there’s no photosynthesis, so phytoplankton wouldn’t be active. That would cut off the base of the marine food web, and there would be no energy entering the system. Everything else would have to enter a resting state, the theories suggested. That would include anything that relied on sight to find food, such as seabirds, since they wouldn’t be able to see their prey.

Wrong.

A group of researchers led by Jørgen Berge of the Arctic University of Norway in Tromsø spent the winters of 2013, 2014 and 2015 sampling the waters and observing seabird communities in Kongsfjorden, Svalbard, which is north of the Arctic Circle. They found a surprisingly active marine community that in some habitats was actually more diverse than what is found in warmer, sunlit months, the scientists report September 24 in Current Biology.

Without light, phytoplankton are indeed inactive, and there are fewer of them than are found in the spring bloom. But when the researchers artificially lit the plankton, they quickly got to work. They weren’t sleeping — just waiting for the sun to return. Zooplankton, meanwhile, were busy munching away the polar winter, the scientists found. And some, such as Calanus copepods, found that the dark made a great time for mating.

On and near the seafloor, life also kept churning. Iceland scallops kept growing. Traps — which rely on invertebrates crawling inside to get bait — captured gastropods, amphipods and crabs. When the scientists tallied up the invertebrates, they found that the animals’ densities were 10 times greater than what is found in the region in May and October.

Cod and haddock had stomachs half-full of food. And seabirds were observed foraging. Their communities had dwindled, as many birds had migrated south or to the open ocean for the winter. But there were little auks, black guillemots, northern fulmars, glaucous gulls and others. And they were managing to find food. Some were surviving on bioluminescent krill, which were presumably easier to find in the dark. But dissections of stomach contents also found evidence that birds had eaten fish and crustaceans (sadly, also plastic in one glaucous gull).

Scientists had assumed that during the quiet, dark winter, the spring phytoplankton bloom dominated processes in the Arctic system. And management of the region — one that is currently undergoing rapid climate change — was based on that assumption, Berge and his colleagues note. But with the discovery that the ecosystem is active throughout the year, some rethinking may be due.

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83-year-old math problem solved

It took more than 80 years, but a problem posed by a mathematician who delighted in concocting tricky ones has finally been solved.

UCLA mathematician Terence Tao has produced a solution to the Erdős discrepancy problem, named after the enigmatic Hungarian numbers wizard Paul Erdős. Tao’s proof, posted online September 18 at arXiv.org, shows that the difference (or discrepancy) between the quantities of two elements within certain sequences can grow without bound, even if someone does the best possible job of minimizing the discrepancy.

“Based on Tao’s stature, I would trust it straightaway,” even though the proof hasn’t yet been peer-reviewed, says Alexei Lisitsa, a computer scientist at the University of Liverpool in England.

While the problem probably doesn’t have real-world applications, Tao says, “the act of solving a problem like this often gives a trick for solving more complicated things.”

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Don't judge a whale's gut microbiome by diet alone

Baleen whales totally skimp on their veggies, feeding on schools of fish and krill, but the whales share gut microbes with both meat eaters and vegetarians, researchers report September 22 in Nature Communications. 

Researchers combed through poop samples from baleen species, searching for DNA that might hold clues to the types of microbes that inhabit their guts. That turned up genetic codes for proteins helpful for digesting meat, suggesting that whale guts house some similar microbes to those found in fellow carnivores.

But other whale gut microbes looked more like those found in cows, hippos and other land herbivores. That's probably because, like cows, whales have multiple stomach chambers — inherited from their land mammal ancestors. This unusual digestive structure impacts the microbial populations that help whales gradually digest chitin, a carbon compound in tiny crustacean skeletons (a small fraction of the whale diet), the researchers suspect.

The findings add to evidence from giant pandas that evolutionary history and diet both shape the microbes that live in animals' guts.

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Ancient hominid ears were tuned to high frequencies

South African hominids that lived between around 2.5 million and 1.5 million years ago had an ear for high-frequency consonant sounds, anthropologist Rolf Quam of Binghamton University in New York and colleagues report September 25 in Science Advances.

Using CT scans and digital technology, Quam’s team reconstructed the ear anatomies of two Australopithecus africanus skulls and one Paranthropus robustus specimen. Modern human ear measurements guided virtual recreations of soft tissue around ear bones, enabling calculations of audible sound frequencies.

A. africanus and P. robustus could have heard high-frequency consonants associated with the letters t, k, f and s better than either chimps or present-day people do, the team found. An ability to hear, and presumably make, such sounds enhanced communication among hominids foraging in groups across open landscapes, the researchers propose. Such communication need not have required a humanlike language, only vowel and consonant sounds with shared meanings, they say.

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This weekend, lunar eclipse coincides with supermoon

Once in a blue moon, a supermoon turns into a blood moon. During the September 27 total lunar eclipse, the moon will turn a deep crimson when it passes through Earth’s shadow on its monthly closest approach to the planet — something that hasn’t happened since 1982.

The eclipse will run from 9:07 p.m. Eastern Daylight Time to 12:27 a.m. With clear skies, observers from western Europe to central North America could see the entire thing.

This eclipse coincides with a “supermoon” (when the moon passes closest to Earth during a full moon and appears slightly bigger than normal). And just like every eclipse, the moon will reflect the light from simultaneous sunsets and sunrises happening on Earth. That sunlight creates a “blood moon” as it filters through Earth’s atmosphere and casts a dark, ruddy hue.  

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Alpine bee tongues shorten as climate warms

As climate change has warmed the heights of the Rocky Mountains, the anatomy of some specialized bees has changed too, weakening their ancient partnerships with certain alpine flowers.

Two species of long-tongued bumblebees now have tongues that are 24 percent shorter on average than those in specimens from the 1960s and 1970s, says ecologist Nicole Miller-Struttmann of State University of New York College of Old Westbury. These bees do much of the pollinating in high fields of flowers, especially for unusually deep-throated flower species.

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Elusive acid finally created

After more than a century of searching, chemists have finally nabbed a legendary acid.

The acid called cyanoform or tricyanomethane appears widely in textbooks as one of the strongest carbon-based acids known. Yet despite attempts to make the acid dating back to 1896, cyanoform has evaded chemists until now. Researchers report September 18 in Angewandte Chemie International Edition that they isolated the acid by figuring out crucial experimental conditions.

The main problem was temperature, says coauthor Andreas Kornath, an inorganic chemist at Ludwig Maximilian University of Munich. Researchers previously assumed that cyanoform is stable at room temperature. “It is just not,” Kornath says.  Using trial and error, he and his team found that cyanoform is stable only below –40°Celsius.

The acid has a central carbon atom attached to a hydrogen atom as well as to three cyano groups, each consisting of a carbon triple-bonded to a nitrogen. The molecule loses its hydrogen atom very easily, making it a strong acid and demonstrating a fundamental rule of carbon acids. The rule describes how electron-loving groups (in this case, the cyano groups) attached to a central hydrogen-toting carbon pull on that carbon’s electrons. The molecule’s electrons settle into a cozy position close to the cyano groups, leaving the link to the hydrogen extremely weak.

But at room temperature, cyanoform simply decomposes, quickly forming junk molecules, Kornath says.

This is probably what happened in 1896 when chemist Hermann Schmidtmann tried to make cyanoform. Schmidtmann mixed sulfuric acid with a stable relative of cyanoform called sodium tricyanomethanide. That molecule, considered a salt of cyanoform, has the same structure as the acid except it has lost the positive hydrogen ion, resulting in a negative molecule, which is paired with a positive sodium ion.

Schmidtmann expected that sulfuric acid would stick a hydrogen atom onto the negative tricyanomethanide, forming cyanoform. Instead, he ended up with a greenish concoction, probably containing only remnants of the unstable acid.

Several research groups have tried to isolate cyanoform since, repeating Schmidtmann’s experiment or trying new strategies. All failed until now, says Jack Dunitz, a chemical crystallographer retired from ETH Zurich in Switzerland. Cyanoform has been “listed in all the books,” he says. But “it’s doubtful whether it’s ever been made.”

At frigid temperatures, though, Kornath and colleagues finally made the acid, which is a colorless liquid. Similar to Schmidtmann’s method, the researchers reacted a strong acid, in this case hydrogen fluoride, with a salt of cyanoform. Using multiple chemical analyses, they found that the resulting molecule perfectly matched the structure of cyanoform.

“It’s very noteworthy,” says physical chemist Daniel Kuroda at Louisiana State University in Baton Rouge. Theoretical chemistry is simply not good enough to predict temperatures at which substances decompose, he says. But experimental information like this gives chemists new ideas, including thoughts about how to make other acids and salts for fuel cells, for instance. “It opens a lot of doors for chemistry,” he says, “and that’s the most important thing.”

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Black hole collisions evade detection

Supermassive black hole duos are awfully quiet. Searches for spacetime ripples radiating away from these spiraling monsters are coming up empty, a new study reports. The silence is providing hints of the complex interactions at play in the final stage of galaxy collisions.

When galaxies collide, the gargantuan black holes in their cores sidle up to one another. As the two spiral together over billions of years, they radiate gravitational waves. Efforts to detect the cacophony of waves from black hole couples throughout the universe should be turning something up by now. New observations, however, indicate that this “gravitational wave background” is quieter than most theories predict, Ryan Shannon, an astronomer at CSIRO Astronomy and Space Science in Marsfield, Australia, and colleagues report. 

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What makes cells stop dividing and growing

Scientists have discovered a biochemical switch that seals a cell’s fate. 

A buildup of the protein GATA4 forces cells to enter a permanently static state known as senescence, researchers report in the Sept. 25 Science. The discovery sheds light on a complex biological process linked to aging and cancer, and may help scientists better understand and treat aging-related diseases.

Senescence — in which cells stop growing and dividing — results from serious stress and genetic damage, says study coauthor Stephen Elledge, a geneticist at Harvard Medical School. GATA4 helps turn on this response in cells. The researchers found that senescent cells contained higher levels of GATA4, and producing the protein in human connective tissue cells turned the cells senescent.

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New dinosaur identified in Alaska

Arctic dinosaurs have a new poster child.

Ugrunaaluk kuukpikensis, a new species of duck-billed dinosaur, lived in what is now Alaska some 69 million years ago, scientists report September 22 in Acta Palaeontologica Polonica.

A geologist first discovered Ugrunaaluk fossils weathering out of a bluff in 1961. “It took 20 years before anyone actually realized the bones were from a dinosaur,” says Patrick Druckenmiller, a paleontologist at the University of Alaska Fairbanks.

Scientists began expeditions to the bluff in the 1980s and have since discovered thousands of bones buried in mud and siltstone permafrost. But the skeletons had busted apart, and the bones came mostly from youngsters — so figuring out which species were represented was tricky.

Years spent cataloging and comparing bones convinced Druckenmiller’s team that the Cretaceous Arctic had a new species, joining about a dozen other known dinosaurs from the region. The duck-billed dinos lived in polar forests, where yearly temperatures probably averaged around 4°Celsius, he says, roughly as cold as a refrigerator. Living conditions may have been tough: After round-the-clock daylight in the summer, winter would have plunged the dinosaurs into long stretches of darkness.

Adults may have reached nine meters in length, about the length of two full-sized cars parked end to end.

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Having sex doesn’t trigger heart attacks, study suggests

More than 9,000-year-old decapitated head discovered in Brazil

A human skull found in a Brazilian rock-shelter represents the oldest known case of decapitation in the Americas, researchers report September 23 in PLOS ONE.

Radiocarbon dating places the skull at between 9,127 and 9,438 years old, says a team led by André Strauss of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. That’s at least 4,000 years older than previous evidence of severed heads in South America and at least 1,000 years older than reported decapitation cases in North America. The skull might even be the oldest instance of decapitation in the world, Strauss says.

Excavation of a small pit in the rock-shelter in July 2007 produced the skull. A pair of severed hands covered the skull’s face. Incisions on one of six human neck bones in the pit denoted where the individual’s head had been cut off.

Chemical analyses of a fossil tooth indicate that the decapitated person grew up eating local foods, as did 18 other ancient people interred in the rock-shelter. Head removal occurred after death as part of a ritual treatment of the body, Strauss suspects.

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Balloons-and-glue device seals remote wounds inside the body

A pair of balloons and some glue can do the work of surgical stitches.

Stitches — the wound closure method of choice for millennia — can be tricky to use in tight places. So Harvard University bioengineer Ellen Roche and colleagues invented a new tool to deliver light-activated glue patches to remote spots inside the body.

The team used a catheter to thread two balloons and a glue patch through pig organs and even the hearts of living rats. Inflating the balloons pressed patch to tissue. And a fiber optic wire inside one of the balloons shined ultraviolet (UV) light on the glue to make it sticky.

The balloon-and-glue combo could offer surgeons a less invasive way to close up wounds that are more than just skin deep, researchers suggest September 23 in Science Translational Medicine.

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