BALTIMORE — Metamaterials, among the most intricate and skillfully designed configurations of matter ever devised by science, could be improved with the help of Legos.

Famous for their use in cloaking devices, metamaterials are artificial structures that play unnatural tricks with light and sound and other vibrations. Scientists have investigated the use of such materials for soundproofing rooms or protecting buildings from the shaking of earthquakes, among other things. But to do their jobs, metamaterials must be properly designed and fabricated using precisely manufactured components. Testing ideas for new metamaterials is therefore time-consuming and expensive.
So Paolo Celli and colleagues at the University of Minnesota sought alternatives. They considered 3-D printing, Celli said March 15 at a meeting of the American Physical Society. But the printing process can be slow and the “ink” isn’t cheap, so they rejected that idea. “That’s when we thought, ‘Why don’t we use Lego bricks?’” he said. Legos are relatively cheap and can rapidly be rearranged into all sorts of configurations.

Celli and colleagues arranged Lego bricks on a base plate attached to a wooden frame and investigated how the arrangements influenced the way vibrations traveled through the plate. For some arrangements, certain vibration wavelengths could not be transmitted. Manipulation of the Legos allowed the scientists to determine what processes created the forbidden wavelength zones (known as bandgaps), providing valuable data for future designs of real metamaterials.

Further experiments showed how Lego arrangements could identify metamaterial architectures that might provide a shield for buildings at risk from earthquake waves. “We might be able to design a metamaterial shield that might block some frequencies that can be harmful to that structure,” Celli said.

Ahmed Elbanna, a materials researcher at the University of Illinois at Urbana-Champaign, called the work with Legos exciting and said in principle it could be applicable to designing metamaterials for some applications. He said he was “a little bit more skeptical” that it could result in useful earthquake protection.

Celli emphasized that the motivation behind the work was not solely to produce better metamaterials. “We’ve been looking for an agile and versatile experimental platform,” he said, “but we were also looking for something that people can relate to…. We think that this platform is probably very powerful” for promoting this branch of physics to a broader community.

Asked if he played with Legos as a child, Celli replied, “a lot.”

Spiders eat insects. That’s why some of us are reluctant to kill spiders we find at home — we figure they’ll eat the critters we really don’t want around. But a new study reveals that the spider diet is far more diverse than we learned in elementary school. Spiders are insectivores, sure, but many also have a taste for plants.

Only one species of spider is known to be completely vegetarian. Bagheera kiplingi jumping spiders of Mexico survive mostly on bits of acacia trees, Science News reported in 2008. And while scientists have yet to find any other vegetarian species, plant-eating appears to be very common, particularly among jumping spiders and spiders that make webs outdoors.

Martin Nyffeler of the University of Basel in Switzerland and colleagues combed books and journals for reports of spiders consuming plant material. There is evidence of veggie-eating among more than 60 species of spiders, representing 10 families and every continent but Antarctica, the team reports in the April Journal of Arachnology.

Perhaps past scientists can be forgiven for overlooking the plant-eating behavior, as spiders can’t eat solid material. They have a reputation for sucking the juices out of their prey, but that’s not quite the right description. Instead, a spider covers its prey with digestive juices, chews the meat with its chelicerae and then sucks the juices in. This eating style means, though, that spiders can’t just cut a piece of leaf or fruit and chow down.

Some spiders feed on leaves either by digesting them with enzymes prior to ingestion (similar to prey) or piercing a leaf with their chelicerae and sucking out plant sap. Others, such as the vegetarian Bagheera kiplingi, drink nectar from nectaries found on plants or in their flowers. More than 30 species of jumping spiders are nectar feeders, the researchers found.

“During such [feeding], the spiders were seen pushing their mouthparts deep into flowers to drink nectar, similar to the way nectar-drinking insects feed,” the researchers write. And this isn’t accidental behavior — some spiders can feed on 60 to 80 flowers in an hour.

Pollen is probably another common plant-based food source for spiders, especially those that make webs outdoors. That’s because spiders eat their old webs to recycle the proteins. And when they eat their webs, they eat anything that might be caught on the sticky strands, such as calorie-rich pollen. Spiders might also be consuming tiny seeds and fungal spores this way, though the latter may be a risky meal as there are many fungi whose spores will kill spiders.
The researchers also found some cases of spiders intentionally eating pollen and seeds, and they also note that many spiders are eating plant material when they munch on plant-eating insects. Just how common plant-eating is among spiders isn’t yet known, but it could be even more common, especially among species that create webs outdoors.

“The ability of spiders to derive nutrients from plant materials is broadening the food base of these animals,” Nyffeler says. “This might be one of several survival mechanisms helping spiders to stay alive for a while during periods when insect prey is scarce.”

And with reports of spiders eating a whole menu of other non-insect foods — including crustaceans, earthworms and small vertebrates in the wild; and sausage and soy milk in the lab — it’s clear that we need to call them something other than insectivores.

When your barista says today’s cuppa joe has rich, spicy notes found only in Colombia’s soil or ‘terroir,’ he or she might not be completely full of … beans.

Before going global, the coffee bean plant originated in Ethiopia, while cacao was first cultivated in the Amazon. Both coffee and cacao beans undergo fermentation prior to roasting. Wild yeast and other microbes that live on the bean digest the pulp that coats the beans, altering flavor and color as well. Researchers wondered, are these yeasts a product of the plants’ current geography or their original roots?

So, they bought unroasted coffee and cacao beans from 27 countries, isolated bean yeasts and analyzed the yeasts’ genes. While coffee and cacao yeasts are even more diverse than wine yeasts, strains that came from the same continents and countries had more in common genetically with their immediate neighbors. Still, some cacao strains from South America share genes with European vineyard yeast and North American oak tree yeast. Such hybrids are probably the result of human trade and travel, the team reports March 24 in Current Biology.

Determining the flavor fallout of all this yeast diversity requires further study, but wine yeasts from different locales are linked to specific chemical profiles.

Resistance may soon be futile. With machine implants worthy of a Star Trek villain, a new breed of beetle takes walking instructions from its human overlords.

Hirotaka Sato and his colleagues at Nanyang Technological University in Singapore inserted electrodes into flower beetles (Mecynorrhina torquata) to stimulate specific leg muscle groups. By altering the order of electrical zap sequences, the team was able to control a beetle’s gait. Changing the duration of the electrical signals also altered the insects’ speed and step length, Sato and colleagues report March 30 in the Journal of the Royal Society Interface.

Scientists have already made cyborg insects that can fly, scuttle, and crawl, but controlling things like speed could allow biobots to do more complex tasks. Cyborg beetles and other insects provide a more energy efficient and easier-to-assemble alternative to plain old robots and double as a means to study insect locomotion, the researchers argue.

Dome effect dōm ih-fekt n.
Airborne black carbon, also called soot, can cause the dome effect by warming the atmosphere’s top layer and blocking sunlight that would otherwise warm the surface air. The reduced temperature difference between the two layers lowers the boundary between them. This effect traps pollution around major cities, worsening air quality, new research suggests.

Researchers observed the dome effect around several of China’s megacities in December 2013. The compressed near-surface layer of the atmosphere led to thick hazes of pollution, the researchers report online March 16 in Geophysical Research Letters. Reducing local black carbon emissions from industry, biofuel burning, diesel vehicles and coal burning would quickly improve air quality around many megacities, the researchers propose.

The sperm whale is one of the odder-looking cetaceans swimming the oceans. Its massive, blocky head is unlike anything sported by other whales. The space above the mouth holds two large, oil-filled organs stacked one on top of the other — the spermaceti organ on top, and another below it called the (we did not make this up) junk. And in the last couple of decades, scientists have determined that the two organs amplify and direct the sonar clicks that the whales use to navigate in the water.

But there have long been suggestions that the massive head could serve another purpose — to ram other whales. The hypothesis dates back to the 19th century, when sperm whales sometimes rammed — and even sank — whaling vessels. “The structure and strength of the whale’s head is admirably designed for this mode of attack,” wrote Owen Chase, first mate of the Essex, which was sank by a whale and inspired the tale of Moby Dick.

Scientists have largely been leery of this hypothesis, though, in part because ramming would risk damage to organs used to generate sound, and because no one had seen a sperm whale ram another. Or at least no one had ever reported such an event in the scientific literature. But a new study, appearing April 5 in PeerJ, shows that Owen and his whaling buddies just may have been right.

Olga Panagiotopoulou of the University of Queensland in Australia and colleagues created computer simulations of a sperm whale’s head and what might happen when the head rammed another object. Partitions of connective tissue inside the junk, they found, appear to reduce the stresses created by impact, “and thus potentially function as a protective mechanism during ramming,” the team writes.

An impact creates tension in the connective tissue that serves as partitions between pockets of oil in the junk. That tension disperses the impact over a greater volume of the head, protecting both bone and soft tissue from injury. When the connective tissue was removed from the simulations, stresses increased by 45 percent and it became more likely that the skull would crack.

Scars on the heads of sperm whales tend to be around the junk, which may indicate that the whales avoid contact over the spermaceti organ — behind which is the whale’s sound generating system, the researchers note. So if the whales are ramming into one another, they probably can do so without hurting their ability to generate sonar clicks.

But are sperm whales really ramming each other? There is other evidence to suggest they just might be. For one, male sperm whales are as much as three times bigger than females, and such size differences are often found in species in which males compete through fighting. There are those sunken whaling ships, too, which add to the argument that ramming behavior may have been something natural for the whales.
But there’s also a report from a wildlife pilot who, on January 30, 1997, while flying over the Gulf of California, saw two males swim directly toward each other at a speed of about 17 kilometers per hour — and then collide, forehead to forehead.

Just before impact, the whales dove just below the surface of the water. That may explain why no one else has reported such sperm whale contests: If they’re occurring below the water’s surface, a person would have to be directly above the event, or in the water with the whales. And besides, if two 50-ton mammals are about to go head-to-head, it might be best to get out of the way.

The U.S. Environmental Protection Agency, criticized for understating how much methane the United States spews into the atmosphere, has boosted its estimate of total U.S. methane emissions by 13 percent. That’s an increase of more than 3.4 million metric tons of the greenhouse gas and has the same long-term global warming impact as a year’s worth of emissions from about 20 million cars.

The new calculation, released in an EPA report April 15, revises the agency’s U.S. methane emission estimates for 2013 to 28.859 million metric tons, up from the agency’s previous estimate of 25.453 million metric tons. Two-thirds of that increase comes from the natural gas and petroleum sectors, with much of the rest coming from landfills. The report also provides the first estimate of methane emissions for 2014, a slight increase to 29.233 million metric tons.
Globally, methane emissions account for about a quarter of human-caused global warming. Several studies over the last few years have suggested that EPA significantly underestimated the U.S. share of those emissions (SN Online: 4/14/16).

While the new methane estimates are “a step in the right direction,” the agency still has a ways to go, says David Lyon, an environmental scientist at the Environmental Defense Fund. Even with the higher methane estimates, the agency is still undercounting U.S. emissions by about 20 to 60 percent, Lyon says. EPA’s reporting influences U.S. regulation of methane-producing industries such as agriculture and fossil fuel production.

A sizable portion of the still-at-large methane probably comes from “super emitters,” methane sources that contribute a disproportionate share of total emissions. These sources are typically malfunctioning equipment, making them difficult for EPA to account for.

A century and a half ago, a young paleontologist named Othniel Charles Marsh persuaded his uncle, philanthropist George Peabody, to give Yale University $150,000 for a museum of natural history. And so Yale’s Peabody Museum was born, an institution that has repeatedly upended how people understand Earth’s past. In House of Lost Worlds, Richard Conniff tells the story of the Peabody through the curious characters connected to it.
Marsh is arguably the best known, for his fossil-collecting rivalry with Edward Drinker Cope (the infamous Bone Wars) and as the discoverer (or describer) of Stegosaurus, Brontosaurus, Triceratops and Allosaurus, to name a few. Other characters include James Dwight Dana, who Conniff calls “the Linnaeus of the geological world”; G. Evelyn Hutchinson, the father of modern ecology; and Hiram Bingham III, who brought Machu Picchu to public attention in the 1910s (and is thought, by some, to have been the inspiration for Indiana Jones). The book is celebration, not exposé, but Conniff still conveys the researchers’ full personalities, including their competitive natures, along with academic squabbling.

Squeezed in throughout is the story of the building itself — perpetually undersized and often underappreciated — yet, as Conniff seems to remind us, the place where the soul of the science resides. As Hutchinson said, the museum “began to play a great part in my life as soon as I stepped into it.”

Conniff doesn’t go so far as to suggest that the museum makes the man (and, through no fault of Conniff’s, most of the leading characters are men). But he views the Peabody as a rich repository of knowledge. Its walls enclose over 150 years of insights built on discoveries built on insights, ad infinitum. Without the artifacts brought back from Machu Picchu (later returned to Peru after a bitter battle), anthropologists wouldn’t have redefined the site as an estate for Incan emperors. It was Marsh’s studies of dinosaurs, and horses, that positioned the Peabody to teach evolution when others were attacking it. And the first reconstruction of a feathered dinosaur’s colors (SN: 2/27/10, p. 9) depended on a fossilized squid left mostly unnoticed in the Peabody for over a century.

Throughout the book, Conniff emphasizes the discoveries yet to be made and the pleasure of finding out something new. “Please,” he invites readers, “step inside.”

Raging wildfires could burn away efforts to reduce Arctic-damaging soot emissions. Soot produced by burning fossil fuels and plants, also called black carbon, can cause respiratory diseases and greenhouse warming, and can accelerate the melting of ice.

Rising temperatures and changing weather patterns will shift where and how fiercely wildfires burn and spew soot, new simulations show. Outside of the tropics, fire seasons will last on average one to three months longer during the 2090s than they do currently, researchers report online April 8 in the Journal of Geophysical Research: Atmospheres. Soot emissions from wildfires will as much as double in regions that border the Arctic and counteract projected reductions in soot from human activities, the researchers predict.
“Humankind would do well to proactively develop adequate land and fire management strategies to have at least some control on future wildfire emissions,” says study coauthor Andreas Veira, an earth system scientist at the Max Planck Institute for Meteorology in Hamburg.

Predicting the future of fires is difficult because many factors — from weather to vegetation — influence wildfires. Veira and colleagues strung together three different computer simulations that projected the impact of climate change on wildfires (SN Online: 7/15/15). The first predicted future changes in global vegetation, which fed into the second, a wildfire simulation called SPITFIRE. Finally, the researchers plugged their predicted fires into a climate simulation.

If carbon emissions aren’t cut, overall soot emissions from wildfires will stay fairly steady but shift in location. Outside of the tropics, wildfire soot emissions will increase 49 percent by the end of the century as fire seasons get longer, the researchers predict. In the tropics, changing land usage and fewer human-caused ignitions due to urbanization will help decrease emissions there by 37 percent.

A northward shift in wildfires will push more soot emissions toward the Arctic, the researchers warn. Fallen soot darkens ice and snow, accelerating melting (SN: 10/5/13, p. 26). A 2009 study estimated that soot was responsible for more than a third of Arctic warming between 1976 and 2007. The new simulations show that about 53 percent more soot will fall on the Arctic at the end of the century, even if humans cut their own soot emissions in half.

Many factors that could influence future wildfires remain uncertain, says atmospheric scientist Shane Murphy of the University of Wyoming in Laramie. “We shouldn’t take the absolute numbers to mean too much, just to inform us that there’s the potential for severe consequences.”

A year ago, researchers in two small submarines were exploring a seamount — an underwater, flat-topped mountain — off the Pacific coast of Panama when they noticed a dense cloud of sediment extending 4 to 10 meters above the seafloor. One of the submarines approached closer, and the scientists could soon see what was kicking up the cloud: thousands of small, red crabs that were swarming together like insects.

“The encounter was unexpected and mesmerizing,” Jesús Pineda of the Woods Hole Oceanographic Institution in Massachusetts and colleagues write in a paper published April 12 in Peer J.

The team decided to investigate further. They sent an autonomous underwater vehicle to pass over the swarm several times, capturing images and video of the crabs. At the densest points in the swarm, there were more than 70 crabs in a square meter of ocean bottom, and this occurred consistently in a water depth of 350 to 390 meters. The crabs, all 2.3 centimeters in carapace length and larger, were moving together in the same general direction. Some would jump and swim for about 10 centimeters or so before landing back in the pack.
Using one of the submarines, the researchers collected some crabs from the swarm. Back in the lab in Woods Hole, they used DNA barcoding to identify the species: Pleuroncodes planipes. This is the same species of crab that has sometimes washed up in mass stranding events on California beaches, which the team confirmed by comparing the DNA barcodes to those of crabs from a stranding event in La Jolla, Calif., in June 2015.

For reasons that scientists still don’t fully understand, seamounts are ecological hot spots where plankton get trapped and feed a wide array of fish and marine mammals higher up in the food web. Fishermen have figured out that they can take advantage of this, but scientists are just now getting into the game and exploring these sites. Because of this, less than one percent of the world’s seamounts have been checked out by researchers. That probably explains why no one had seen a crab swarm like this before on a seamount.
But this is not the first time crabs have been seen swarming. Scientists have previously documented large aggregations of king crabs, spider crabs, tanner crabs and lyre crabs on the seafloor. Such behavior may be linked to reproduction.

And then there are the red crabs of Christmas Island in the Indian Ocean, which swarm in the millions during the wet season, coming out of the forests and making a long trek to the beach for a massive mating party.