News and notes about science
EMPEROR PENGUINS: GOOD DADS, BUT LESS DEDICATED THAN YOU MAY HAVE THOUGHT
When it comes to heroic dads, it’s hard to outdo the emperor penguin. But a new study suggests the reality may fall short of the legend.
Male emperor penguins are famous for going without food for up to 115 days while they mate and then shelter a solitary egg from the brutal winter winds. Dramatic footage of the semiannual ritual, which begins with a 100-kilometer Antarctic trek to an inland breeding ground, helped make 2005’s “March of the Penguins” one of the highest grossing documentaries of all time.
But researchers who visited a different colony say they witnessed the animals taking breaks from their breeding duties to go fishing in the winter darkness, challenging the popular notion that they are nature’s most dedicated dads.
The behavior was witnessed at Antarctica’s Cape Washington in late May 1998 — after breeding season had begun and the sun had permanently set for the winter — by a team led by Gerald L. Kooyman, a marine biologist at the Scripps Institution of Oceanography at UCLA, San Diego.
By the end of their visit to the cape, they had witnessed more than 100 emperor penguins either swimming or returning from the sea.
Before they left, the researchers tagged four birds with satellite tags and “water switches” that allowed them to track how far the animals traveled and how often they entered the sea. The data confirmed that the penguins continued to take moonlight swims throughout the breeding season. The researchers believe the males ceased their hunting activity once the females laid their eggs.
The findings, published in the Journal of Experimental Biology, suggest that previous research on emperor penguins was focused on too small a population to be taken as representative for the entire species, Kooyman said.
“Almost all the studies about winter breeding have been conducted from the research station Dumont D’Urville, which is about 100 meters away from a colony,” he said. That colony is also 100 kilometers from the ice edge, making it impossible for penguins that breed there to take breaks for fishing. Douglas Quenqua
FINDING THE OLDEST FOSSILS OF BUTTERFLIES USING A HUMAN NOSE HAIR
Any curious kids who have caught a butterfly by hand, only to find their fingers coated in messy powder, have unknowingly brushed off the fluttering insect’s scales. These microscopic plates cover almost every part of a butterfly, and are what help paint their wings a variety of colors, from shimmering cobalt blues to patterns of orange and black.
While most people go to a garden if they want to see a butterfly’s scales in action, Timo van Eldijk’s search for wing scales required drilling more than 1,000 feet into the ground. Then, he extracted fossilized insect bits from black sludge using a probe tipped with human nose hair.
In a study published last week in the journal Science Advances, van Eldijk and his colleagues uncovered approximately 200-million-year-old wing scales belonging to ancient members of the insect order Lepidoptera, (named for the Greek words for “scale” and “winged”) which include butterflies and moths.
“These scales are the oldest evidence of moths and butterflies,” said van Eldijk, who was an undergraduate at Utrecht University in the Netherlands during the research. “It extends the range to which we know butterflies existed by about 10 million years.”
The scales may also provide insight into the early evolution of the insect’s tubelike tongue, or proboscis, which the authors suggest evolved tens of millions of years before nectar-rich flowers existed.
Van Eldijk made the discovery while working with Bas van de Schootbrugge, a geoscientist at Utrecht University, on a project to investigate ancient pollen in the fossil record. For that project, the team drilled deep below northern Germany to collect sediment from the time of the extinction event. They then dissolved the rock in chemicals that eat away any material that was not organic, leaving pollen samples behind in a black goop.
But in analyzing the murky solution they stumbled upon a new mystery: several unknown scales were left behind in the gunk. The team soon discovered that the scales belonged to long extinct relatives of modern butterflies and moths.
He and his team uncovered about 70 scales or scale fragments, which they dated to about 200 million years ago. Nicholas St. Fleur
IN WINTER, YOU MIGHT WISH YOU HAD THIS RODENT SUPERPOWER
Most rodents are just rodents. And the ones with exceptional abilities are usually cartoon rats or mice.
But some woodland rodents really do have a superpower that helps them tolerate cold and endure harsh winters.
In grasslands from central Canada to Texas, members of a species known as thirteen-lined ground squirrels can adjust their body temperature to match
the air around them. This is especially important during hibernation: They don’t have to fatten up like bears or find warm hideouts like conventional mice and rats. They slumber, surviving in bodies just above freezing. Another species, the Syrian hamster, does it too. “They combine warm and cold blooded animals in one,” said Elena Gracheva, a neurophysiologist at Yale University.
This uncanny ability to withstand prolonged cold (and even hypothermia) results in part fan adaptation these rodents have developed in molecules they share with other mammals, including us, Gracheva and her colleagues found in a study published last month in the journal Cell Reports. Unique properties of TRPM8, a cold sensing protein found in their peripheral nervous systems, shields these rodents from harsh weather. It’s really important because if they’re too cold, they can’t hibernate.
The new research brings scientists closer to understanding enigmas of hibernation and solving a mystery of how this molecular sensor works. The work also may lead to therapies for allodynia, a nerve condition that causes some people to misperceive something normally not-so-cold as painful.
TRPM8 is an ion channel located on some neurons in skin covering the body and face. When exposed to cold air or certain chemicals, like menthol, the pores open, allowing a flood of ions into the cell like cool air through a window. This sends a signal to the central nervous system.
But something is different in the TRPM8 of thirteen-lined ground squirrels and Syrian hamsters.
In one test involving surfaces of varying temperatures, researchers found that squirrels and hamsters (to a lesser extent) didn’t seem to notice a temperature gradient that for us might be like the difference between jacket-and-jeans or tank-top-and-shorts weather. Mice were very aware of these temperature differences.
The team found a set of amino acids inside the channel that were the source of the ground squirrel’s seeming imperviousness to cold down to a certain temperature. Joanna Klein
IF WE EVER GET TO MARS, THE BEER MIGHT NOT BE BAD
Here’s an interplanetary botany discovery that took college students and not NASA scientists to find: Hops — the flowers used to add a pleasant bitterness to beer — grow well in Martian soil.
“I don’t know if it’s a practical plant, but it’s doing fairly well,” said Edward F. Guinan, a professor of astronomy and astrophysics at Villanova University.
Last semester, 25 students took Guinan’s class on astrobiology, about the possibility of life elsewhere in the universe.
For the laboratory part of the course, the students became farmers, experimenting to see which crops might grow in Martian soil and feed future travelers there.
Of course, no one has yet brought back anything from the red planet, but spacecraft like NASA’s Phoenix Mars lander have analyzed Martian soil in great detail. Based on those measurements, scientists have come up with a reasonably good reproduction on Earth — crushed basalt from an ancient volcano in the Mojave Desert. It’s available for purchase, and Guinan bought 100 pounds.
Martian soil is very dense and dries out quickly — perhaps better for making bricks than growing plants, which have trouble pushing their roots through.
For the most part, the students chose practical, nutritious plants like soy beans and kale in addition to potatoes. And one group chose hops. “Because they’re students,” Guinan said. “Martian beer.”
For the experiments, the students had a small patch of a greenhouse, with a mesh screen reducing the sunlight to mimic Mars’ greater distance from the sun.
What did “fabulous” in pure Martian soil was mesclun, a mix of small salad greens, even without fertilizer, Guinan said.
When vermiculite, a mineral often mixed in with heavy and sticky Earth soils, was added to the Martian stuff, almost all the plants thrived. Because astronauts would likely not be hauling vermiculite from Earth but might have cardboard boxes, Guinan also tried mixing cutup cardboard into the Martian soil. That worked too. Kenneth Chang
THE STRANGE ORIGIN OF A MANAKIN’S GOLDEN CROWN
Three related species of manakins occupy adjacent parcels of the Amazon rain forest: Opal-crowned, snowcapped and golden-crowned. They are all plump like sparrows, small enough to cup in a hand and have radiant yellow-green upper bodies with golden undersides.
Biologists are now unlocking the mystery of how these neighboring birds became distinct species. Recently, a team of scientists confirmed in Proceedings of the National Academy of Sciences that the golden-crowned manakin is a unique hybrid species that emerged from a cross between the opal-crowned and snow-capped manakins about 180,000 years ago.
Though one-off mating events between different species occur across the animal kingdom, the establishment of an entirely separate hybrid species is thought to be relatively rare.
For a new species to occur, it has to become reproductively isolated, or form a stable population that no longer freely mixes with its parent species, said Alfredo Barrera-Guzmán, who led the new research as a doctoral student at the University of Toronto Scarborough.
Opal-crowned manakins wear an iridescent toupee, evocative of a unicorn’s mane. Snow-capped manakins are topped with bright glacial patches. And members of the hybrid species, the golden-crowned manakin, display a burst of yellow to match their bellies. Choosy females prefer the particular color sported by males of their own species, leading to reproductive isolation.
Hybrids often look like an intermediate between their parent species, which made scientists skeptical that you’d get a golden-crowned manakin by crossing opal-crowned and snowcapped manakins.
Scientists found that the manakin’s warm crown comes from pigments called carotenoids, which the birds get from their diet. When chemically stripped of these pigments, the feathers turned grayish-white.
Barrera-Guzmán’s team suspects that the first male mixes between snow-capped and opal-crowned manakins bore this dull tuft, an intermediate between the white and iridescent caps of their forebears.
As the hybrids evolved in a segregated space, females may have preferred to mate with males that had a higher concentration of carotenoids in their crown, producing an attractive yellow blaze, said Jason Weir, an associate professor of evolutionary biology at the University of Toronto Scarborough and senior author of the new paper. Steph Yin