Every autumn, a quiet mountain pass in the Swiss Alps turns into an insect superhighway. For a couple of months, the air thickens as millions of migrating flies, moths and butterflies make their way through a narrow opening in the mountains. For Myles Menz, it’s a front-row seat to one of the greatest movements in the animal kingdom.

Menz, an ecologist at the University of Bern in Switzerland, leads an international team of scientists who descend on the pass for a few months each year. By day, they switch on radar instruments and raise webbed nets to track and capture some of the insects buzzing south. At sunset, they break out drinks and snacks and wait for nocturnal life to arrive. That’s when they lure enormous furry moths from the sky into sampling nets, snagging them like salmon from a stream. “I love it up there,” Menz says.
He loves the scenery and the science. This pass, known as the Col de Bretolet, is an iconic field site among European ecologists. For decades, ornithologists have tracked birds migrating through. Menz is doing the same kind of tracking, but this time, he’s after the insects on which the birds feast.

Migrating insects, like those that zip through the Swiss mountain pass, provide crucial ecosystem services. They pollinate crops and wild plants and gobble agricultural pests.

“Trillions of insects around the world migrate every year, and we’re just beginning to understand their connections to ecosystems and human life,” says Dara Satterfield, an ecologist at the Smithsonian Institution in Washington, D.C.

Scientists like Menz are fanning out across the globe to track butterflies, moths, hoverflies and other insects on their great journeys. Among the new discoveries: Painted lady butterflies time their round trips between Africa and Europe to coincide within days of their favorite flowers’ first blossoms. Hoverflies navigate unerringly across Europe for more than 100 kilometers per day, chowing down on aphids that suck the juice out of greening shoots. What’s more, some agricultural pests that ravage crops in Texas and other U.S. farmlands are now visible using ordinary weather radar, giving farmers a better chance of fighting off the pests.
Until now, most studies of animal migration have focused on large, easy-to-study birds and mammals. But entomologists say that insects can also illuminate the phenomenon of mass movement. “How are these animals finding their way across such large scales? Why do they do it?” asks Menz. “It’s really quite fantastic.”
To warmer worlds
Animals migrate for many reasons, but the aim is usually to eat, breed or otherwise survive year-round. One of the most famous insect migrations, of North America’s monarch butterflies (Danaus plexippus), happens when the animals fly south from eastern North America to overwinter in Mexico’s warmer setting. (A second population from western North America overwinters in California.) In Taiwan, the purple crow butterfly (Euploea tulliolus) migrates south from northern and central parts of the island to the warmer Maolin scenic area every winter, where the butterfly masses draw crowds of lepidopteran-loving tourists. In Australia, the bogong moth (Agrotis infusa) escapes the hot and dry summer of the country’s eastern parts by traveling in the billions to cool mountain caves in the southeast.

The migrations can be arduous. Each spring, the painted lady butterfly (Vanessa cardui) moves out of northern Africa into Europe, crossing the harsh Sahara and then the Mediterranean Sea before retracing the route in the autumn (SN Online: 10/12/16). Because adult life spans are only about a month, the journey is a family affair: Up to six generations are needed to make the round trip. It’s like running a relay race, with successive generations of butterflies passing the baton across thousands of kilometers.
Constantí Stefanescu, a butterfly expert at the Museum of Natural Sciences in Granollers, Spain, has been tracking the painted lady migrations. He relies on citizen scientists who alert him when the orange-and-black-winged painted ladies arrive in people’s backyards each year, as well as field studies by groups of scientists. In 2014, 2015 and 2016, Stefanescu led autumn expeditions to Morocco and Algeria to try to catch the return of the painted ladies to their wintering grounds.

By surveying swaths of North Africa, Stefanescu’s team confirmed that the painted ladies virtually disappeared from the area during the hot summer months and returned in huge numbers in October. The fliers arrived back in Africa just in time to feed on the daisylike false yellowhead (Dittrichia viscosa) and other flowers. The findings make clear how well the butterflies are able to time their migrations to take advantage of resources, Stefanescu reported in December in Ecological Entomology.
Other insect species are less visibly stunning than the painted lady, but just as important to the study of migrations. One emerging model species is the marmalade hoverfly (Episyrphus balteatus), which migrates from northern to southern Europe and back each year.

Marmalade hoverflies have translucent wings and an orange-and-black striped body. As larvae, they eat aphids that would otherwise damage crops. As adults, the traveling hoverflies help pollinate plants. “They’re useful for so many things,” says Karl Wotton, a geneticist at the University of Exeter in England.

Wotton started thinking about the importance of insect migration after 2011, when windblown midges carried an exotic virus into the southern United Kingdom that caused birth defects in cattle on his family’s farm. Intrigued, Wotton set up camp at a spot in the Pyrenees at the border of Spain and France to study migrating hoverflies. Then he heard that Menz was doing almost exactly the same kind of research at the Col de Bretolet and a neighboring pass. The two connected, hit it off and now collaborate in both the Pyrenees and the Alps.
Funneled by the high mountain topography, hoverflies whiz through the passes like rush hour commuters through a railway station. “We’re talking about an immense number of insects,” Menz says. Millions of flies traverse the Swiss passes each year. Extrapolating to all of Europe, Wootton estimates that many billions of hoverflies are probably migrating. The insects consume billions of aphids that otherwise would have feasted on agricultural crops.

As astonishing as this migration is, most people never notice it. Only at the passes do the hoverflies become noticeable, a never-ending stream of tiny bodies glinting in the mountain light. They ride high on tailwinds and scoot low when the wind is against them. “They fly fast and low and they don’t stop,” Wotton says. “The butterflies are getting turned around like in a tumble dryer, but the hoverflies just shoot straight over.”

Wotton, Menz and colleagues use specialized upward-looking radar to track signals reflecting off of insects passing overhead. The researchers also use traps to catch individual flies to identify the species passing through.
And they study navigation in a sort of hoverfly flight simulator. The researchers glue the backs of flies to the heads of pins and watch how the flies navigate when held between two magnets. The aim is to see if the insects are using cues from Earth’s magnetic field to find their way. Suspended between the magnets, the insects can move freely left or right, choosing their direction of travel. The whole contraption is enclosed in an opaque plastic barrel so the flies cannot see the visual cues of the surrounding mountains. Preliminary findings suggest the flies do indeed find their way using some kind of compass, Wotton reported in Denver in November 2017 at a meeting of the Entomological Society of America.
Season after season, the researchers are building up a hoverfly census. By comparing that information with a 1960s survey done at the Col de Bretolet, the team hopes to determine whether species’ numbers have changed over time. Menz says: “I wouldn’t be surprised if they’ve declined.”

Other entomologists have documented sharp drops in the numbers of insects across Europe. In October 2017, a Dutch-German-British research team reported in PLOS ONE that the total insect biomass collected at 63 nature-protection areas in Germany over 27 years had dropped by more than 76 percent.

The paper garnered media headlines around the world as heralding an “insect Armageddon.” That may be overly dramatic. The work covered just one small part of Europe, and the authors could not explain what might be causing the drop, whether climate change, habitat destruction or something else. But if hoverfly numbers are dropping, that would mean fewer are around to eat destructive aphids and to spread beneficial pollen. Hoverflies, which pollinate a wide range of plants, are the second most important group of pollinators in Europe after bees, Wotton says.
Hoverflies also migrate in North America, in ways that are far less understood than in Europe. This month, Menz and Wotton are visiting Montaña de Oro State Park on California’s Central Coast, where last year an entomologist reported spotting a rare hoverfly migration. The researchers hope to see whether the American hoverflies, probably a different species, are moving in the same ways their European cousins do.

Swoop in the destroyers
Not all migrating insects are beneficial. Some are troublemakers that chase ripening crops with the season. Farmers can spray pesticides once insects arrive in the fields, but knowing more about when and where to expect the critters can help growers better prepare for the onslaught.

Weather radar — Doppler data that meteorologists use to follow rain, hail and snow in near real time — is beginning to help. The radar signals reflect off of birds and other animals flying through the air. And although many insect species are too small to be detected in Doppler radar data, researchers are finding new ways to extract the signals of insects and track their migrations as they happen.

John Westbrook, a research meteorologist at the U.S. Department of Agriculture’s Agricultural Research Service in College Station, Texas, has been using weather radar to follow insect flyways in the south-central United States. A 1995 outbreak of two migratory moth species — beet armyworm (Spodoptera exigua) and cabbage looper (Trichoplusia ni) — devastated cotton crops in Texas’ Lower Rio Grande Valley. Westbrook recently dug through the Doppler data from 1995 and was able to pick out the signals of these two species moving during the outbreak, Westbrook and USDA colleague Ritchie Eyster wrote in November 2017 in Remote Sensing Applications: Society and Environment.
“Outbreaks are unpredictable,” Westbrook says. “But the weather radar can show where they are occurring.” Modern weather radar contains even more information than 1995 systems did, he notes — and farmers can use that data to their advantage. They may decide to spray heavily where most of the insects are gathering before they spread. Or farmers might stock up on pesticides if a particularly dangerous outbreak is headed in their direction.

Another way to track destructive insects is to grind them up and test the chemistry of their tissues. As caterpillars grow, they take on a characteristic chemical signature of the environment, with hydrogen, oxygen and other elements fixed in tissues in varying amounts. Analyzing those ratios can reveal the geographic region of a caterpillar’s origin.

Keith Hobson of Western University in London, Canada, and colleagues have been studying the insect pest known as the true armyworm moth (Mythimna unipuncta). It travels between Canada and the southern United States every year, damaging crops along the way. But scientists weren’t sure exactly where the insects originated each year, making it harder to figure out how to manage the problem with pesticides.

In new experiments, Hobson’s team captured true armyworm moths in Ontario throughout the year and analyzed the hydrogen retained within the moths’ wings. Moths captured early in the season had values similar to those seen in Texas waters, while those captured in the summer showed values closer to Canadian waters. The reverse was also true: Adult moths captured in autumn in Texas had Canadian-type values.

It is the first direct evidence that individual moths are making these long-distance round trips, the scientists wrote in January in Ecological Entomology. Further studies could reveal how to better control the pests throughout the growing season, by showing precisely where the insects are coming from and how far they will travel.
The migrating masses
For Menz, Wotton, Satterfield and the rest, the ultimate goal is to go from studying individual species to investigating broader questions of how and why animals move around. That includes exploring how insects alter food webs during migrations across the landscape.

For instance, Mexican free-tailed bats (Tadarida brasiliensis) in Texas and Mexico forage for nocturnal moths, which migrate in very narrow layers in the atmosphere based on how the wind is blowing. “These are like food webs in the sky,” says Jason Chapman, an ecologist at the University of Exeter. “Can bats read the weather patterns and predict where the insects are going to be?”

Similarly, many dragonflies attempt to migrate 3,500 kilometers or more across the Indian Ocean from India to east Africa and back each year, breeding in temporary ponds created by monsoon rains. The dragonfly-eating Amur falcon (Falco amurensis) makes a similar journey, in one of the longest-known migrations for any raptor. If the dragonflies are the reason for the falcon migration, then tiny insects are a major player in this important bird movement.

Insects rule the migratory world by virtue of their sheer numbers. Compared with birds, mammals and other migratory animals, insects are by far the most numerous. Roughly 3.5 trillion migrate each year over just the southern United Kingdom, a 2016 radar study suggested (SN: 2/4/17, p. 12). That means that the majority of land migrations are made by insects.

To Aislinn Pearson, an entomologist at Rothamsted Research in Harpenden, England, studying insects will boost scientific understanding of how animals flow around the planet. “In the next 10 years,” she says, “a lot of the key findings of migration are going to come from these tiny little animals.”

Moody red lighting in a lab is helping researchers figure out what fruit flies like best about sex.

The question has arisen as scientists try to tease out the neurobiological steps in how the brain’s natural reward system can get hijacked in alcoholism, says neuroscientist Galit Shohat-Ophir of Bar-Ilan University in Ramat Gan, Israel.

Male fruit flies (Drosophila melanogaster) were genetically engineered to ejaculate when exposed to a red light. Ejaculation increased signs in the insects’ brains of a rewarding experience and decreased the lure of alcohol, researchers found. After several days in this red-light district, the flies tended to prefer a plain sugary beverage over one spiked with ethanol. Males not exposed to the red light went for the boozier drink, Shohat-Ophir and colleagues report April 19 in Current Biology.
Earlier lab research has shown that male flies repeatedly rejected by females are more likely to get drunk. Those with happy fly sex lives don’t show much interest in alcohol. Shohat-Ophir wondered what aspect of sex, or lack thereof, had such a profound effect on the brain’s reward system.

The answer wasn’t that obvious. In rats, for instance, the brains of first-timer males light up with intense biochemical signs of reward just from rodent intercourse, regardless of whether ejaculation occurs. In female rats, copulation needs the right circumstances to evoke reward chemistry.

The red-light system let researchers remove the possibly confounding factor of female presence and see that male flies find ejaculation itself rewarding. (Among the evidence: pairing the red light with an odor cue, which males eagerly sought out afterward.) The red light triggers what are called Crz nerve cells in the abdomen, which cause sperm release and a surge of neuropeptide F, a cousin of a human brain reward compound called neuropeptide Y.
Male flies’ bedazzlement with the right light or drinking binges after rejection may be easy for humans to understand. Shohat-Ophir says that’s because brain reward chemistry is so ancient that parts of it have been inherited by creatures with six legs as well as two.

Two major groups of plants have shown a surprising reversal of fortunes in the face of rising levels of carbon dioxide in the atmosphere.

During a 20-year field experiment in Minnesota, a widespread group of plants that initially grew faster when fed more CO2 stopped doing so after 12 years, researchers report in the April 20 Science. Meanwhile, the extra CO2 began to stimulate the growth of a less common group of plants that includes many grasses. This switcheroo, if it holds true elsewhere, suggests that in the future the majority of Earth’s plants might not soak up as much of the greenhouse gas as previously expected, while some grasslands might take up more.
“We need to be less sure about what land ecosystems will do and what we expect in the future,” says ecosystem ecologist Peter Reich of the University of Minnesota in St. Paul, who led the study. Today, land plants scrub about a third of the CO2 that humans emit into the air. “We need to be more worried,” he says, about whether that trend continues.

The two kinds of plants in the study respond differently to CO2 because they use different types of photosynthesis. About 97 percent of plant species, including all trees, use a method called C3, which gets its name from the three-carbon molecules it produces. Most plants using the other method, called C4, are grasses.
Both processes ultimately feed plants by pulling carbon dioxide from the air. But C4 plants use CO2 more efficiently, so they’re less hungry for it. As a result, it has long been dogma that when CO2 increases in the air, C3 plants gobble up more of it — and thus grow faster — while C4 plants ignore it.
And that’s what experiments on plants grown in elevated CO2 have always shown — until now. For 20 years, scientists at the Cedar Creek Ecosystem Science Reserve in Minnesota have grown both C3 and C4 grasses in 88 plots, pumping extra CO2 into half of them to increase concentrations by 180 parts per million. That amounts to about 50 percent more CO2 than was in ambient air at the experiment’s beginning, and double preindustrial levels.

For the first 12 years, the plants hummed along as expected, with C3 plants responding more strongly to extra CO2 — a 20 percent boost in growth compared with plants grown in ambient air — and C4 plants largely ignoring the difference. But then something unexpected happened: The pattern reversed. Over the next eight years, C3 plants grew on average 2 percent less plant material if they received extra CO2, while C4 plants grew 24 percent more.

“I’m not at all surprised that an experiment like this would produce the unexpected,” says forest ecologist Rich Norby of Oak Ridge National Laboratory in Tennessee. Norby led a different project that tested a forest’s response to elevated CO2 for 12 years, and says the new results highlight the importance of such long-term experiments.

In particular, Norby says, soil fertility can affect how plants respond to CO2 in the long run.

In fact, soil nutrients may have been key to the flip-flop in Minnesota. Without the nitrogen they need, plants can’t take advantage of extra CO2 no matter how much there is. Over the course of the experiment, nitrogen grew to be in shorter supply for C3 plants, but in greater supply for C4 plants. The team suspects that differences in decomposing plant material might have led to changes over time in the community of microbes that process nitrogen in the soil and make it available to plants.

Since grasslands cover 30 to 40 percent of Earth’s land area, Reich says it’s important to learn how they could store carbon in the future. If grasslands worldwide behave as in the experiment, C4 grasslands — found in warm, dry regions — may absorb more CO2 than thought, while more abundant C3 plants could soak up less. As for crops, which can be either C3 like wheat or C4 like corn, the future is even less clear since farmlands are highly managed and often fertilized with nitrogen.

More studies are needed to figure out whether, and how, the world’s plants could shift in their response to increasing CO2. In the meantime, says Reich, “this means we shouldn’t be as confident we’re right about the ability of … ecosystems to save our hides.”

Uranus’ upper clouds are made of hydrogen sulfide — the same molecule that gives rotten eggs their noxious odor.

“At the risk of schoolboy sniggers, if you were there, flying through the clouds of Uranus, yes, you’d get this pungent, rather disastrous smell,” says planetary scientist Leigh Fletcher of the University of Leicester in England.

Using a spectrograph on the Gemini North telescope in Hawaii, Fletcher and his colleagues detected the chemical fingerprint of hydrogen sulfide at the top of the planet’s clouds, the team reports April 23 in Nature Astronomy.

That wasn’t a complete surprise: Observations from the 1990s showed hints of hydrogen sulfide lurking deeper in Uranus’ atmosphere. But the gas hadn’t been conclusively detected before.
The clouds aren’t just smelly — they can help nail down details of the early solar system. Uranus’ hydrogen sulfide clouds set it apart from the gas giant planets, Jupiter and Saturn, whose cloud tops are mostly ammonia.

Hydrogen sulfide freezes at colder temperatures than ammonia. So it’s more likely that frozen hydrogen sulfide ice crystals would have been abundant in the further reaches of the early solar system, where the crystals could have glommed onto newly forming planets. That suggests that ice giants Uranus and Neptune were born farther from the sun than Jupiter and Saturn.

“This tells you the gas giants and the ice giants formed in a slightly different way,” Fletcher says. “They had access to different reservoirs of material back in the forming days of the solar system.”

Fletcher is far from repelled by the malodorous clouds. He and other planetary scientists want to send a spacecraft to the ice giants — the first since the Voyager spacecraft visited in the 1980s — to find out more (SN: 2/20/16, p. 24).

I am not the first person who has considered composing poetry to the placenta. One writer begins: “Oh Lady Placenta! What a life you lived in magenta.” Another almost coos to the “constant companion, womb pillow friend.” It might sound like odd inspiration for verse, but it’s entirely justified.

This vital organ, which is fully formed by about 12 weeks, nurtures a growing fetus throughout pregnancy, offering oxygen, nutrients and antibodies and eliminating waste. The placental cells forge a deep connection between mom and baby, a symbolic early step in a lifelong bond.
Recent research suggests a placenta that works properly might be even more important than previously thought. Myriam Hemberger of the Babraham Institute and the University of Cambridge, along with colleagues in England and Austria, looked at more than 100 genes in mice that are known to be necessary for an embryo to survive. More than two-thirds of those mouse genes were linked to problems with the placenta. And death of the embryo around days 10 to 15 —when, in mice, the placenta takes over from the yolk sac to supply nutrients — was almost always tied to these placental problems.

The study makes you wonder: How many birth defects in humans might have their roots in the placenta? “You cannot just look at the embryo,” says Susan Fisher of the University of California, San Francisco, who studies how placental cells invade the uterus early in pregnancy. “You should work backward from the placenta.”

Both Hemberger and Fisher believe the placenta is underappreciated. I certainly thought much more about my little embryo turned fetus, growing from sesame seed to grape-sized, grapefruit and beyond, than I did about the disk of tissue supporting my baby-to-be. Fisher calls the placenta “the forgotten organ.”

In 2013, Tina Hesman Saey wrote a feature in Science News about new and growing efforts to understand the placenta. The New York Times published a story the following year, headlined “The Mysterious Tree of a Newborn’s Life.”
Then came the launch of the Human Placenta Project, an initiative of the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Since 2015, the project has invested more than $65 million in the development of technologies that can study the placenta in its natural environment, while a woman is pregnant.

“There is a long history of research involving the placenta, for many, many years,” says neonatal geneticist Diana Bianchi, director of the NICHD, who calls the placenta the Rodney Dangerfield of organs. Like the comedian, it gets no respect. “But the research had pretty much exclusively been after delivery.”

Shortly after a baby is born and his umbilical cord is cut, the placenta is expelled from the mother. At that point, it’s straightforward to inspect its size and blood vessels, and to see if scarring or calcium deposits provide clues to poor function. But it’s much too late to predict a fetus in trouble or to intervene in any way that might ultimately protect mom or baby.

Through the Human Placenta Project, researchers are, for example, using ultrasound to investigate placental blood vessels and blood flow in 3-D during the middle trimester and using magnetic resonance imaging to study oxygen distribution in twins who share a placenta but have separate amniotic sacs. How and when such work might make it to the clinic to affect current and future mommies isn’t yet clear.

Bianchi predicts that a deeper appreciation of the role of the placenta, encouraged through Hemberger’s work and similar studies, could change how pregnant women are monitored in the United States. There’s currently very little monitoring for women in the earliest weeks of pregnancy, the window when the placenta is becoming established. Doctor visits then ramp up as the pregnancy progresses. More attention in the first trimester, including attention to the placenta, could identify women who might be at a high risk for stillbirth or premature delivery, even if they are young and healthy by other standards. “That is a very conceivable, no pun intended, but very likely outcome of this research,” Bianchi says.

After identifying so many genes that affect the placenta, Hemberger’s team went on to show that many of those genes are associated in mice with blood vessel, heart and brain problems in a developing fetus. In other words, problems in the heart may have begun elsewhere, in the placenta. Among three of the mouse genes studied in much more detail, the researchers identified one for which the placenta problem was solely responsible for the death of the embryo at around 10 days. Even if the gene was absent from the embryo, restoring it to the placenta could prolong the embryo’s survival.

If the work holds for humans, it might mean that a fix to the placenta could change the course for a dramatic number of babies who would otherwise be born too small or with birth defects. That’s powerful stuff for would-be moms.

And there’s much more work to be done. “You need to understand normal development before you can address anything that goes wrong,” Hemberger says. A lot of pregnancy complications, including those related to the placenta, originate in the first two to eight weeks, which is still “the black box,” she says.

Recent research out of Japan may help. In January, a team there announced deriving and growing human trophoblast stem cells, the cells that form a large part of the placenta. Though such cells have been studied from mice, this could mark the beginning of more fruitful, detailed efforts to understand placenta formation in people. “Approaches like this,” Hemberger says, “can open up what happens in these early stages.”

Once more is known about how it all begins, it may feel perfectly natural for every person born to sing the praises of the placenta, “The tree of life, the mother-child link, Nourishing baby before it can drink.”

Stephen Nicol is here to change your mind about krill: They’re not microscopic and they’re far from boring. The biologist is so sick of people misunderstanding his study subjects that he’s even gotten a (slightly botched) krill tattooed on his arm to help enlighten strangers.

In The Curious Life of Krill, Nicol is taking his mission to an even bigger audience. The book is an ode to Antarctic krill (Euphausia superba), which are among the most abundant animals in the world by mass. Each several centimeters long, krill cloud the ocean in swarms that can span 20 kilometers. They’re a linchpin of ocean ecosystems — a key food source for whales, penguins and other marine life. And yet, Nicol points out, few people would be able to identify these translucent, red-and-green-speckled creatures with feathery appendages.
Anyone who has ever nurtured an affection for a species that others find odd or distasteful or unremarkable will understand Nicol’s devotion. His wry and earnest way of describing krill and their ecology will probably draw in those interested in biology or environmental science.
As one of the world’s leading experts on krill, Nicol offers an insider’s view of the political negotiations over krill fishing in the Southern Ocean. And yet the book’s conversational (sometimes slightly rambling) style makes you feel as if you’re part of an engaging dinnertime conversation. Nicol chronicles the challenges of estimating krill populations and of studying the complex behavior of an animal too small to tag or track. And he shares plenty of delightful anecdotes. At one point, for instance, his lab amassed the world’s largest collection of whale poop to study whether the cetaceans could fertilize the surface ocean by recycling the nutrient iron picked up through the krill they ate. The answer: probably yes.
The book tackles tougher subjects, too. Nicol delves into the threats that Antarctic krill face from fishing — the animals are gathered up for aquaculture feed and also ground into extracts and powders for dietary supplements and medical research — and describes efforts to regulate the industry. He ponders how krill may fare in warming oceans. The critters are resilient, he says, but it’s not clear how quickly these animals, which are known to live as long as about a decade, will adapt to rapidly changing sea temperatures.

Like millions of parents, I post pictures of my kid on Instagram. When she was born, her father and I had a brief conversation about whether it was “dangerous” in a very nebulous sense. Comforted by the fact that I use a fake name on my account, we agreed to not post nudie pics and then didn’t give it much more thought. Until recently.

As she gets older, and privacy on social media dominates the news, I’m revisiting this conversation. Am I invading my daughter’s privacy by sharing her kooky dance moves or epic Nick Nolte hair? Will she feel violated when she’s older? My generation had to contend with mom showing an embarrassing baby photo to our prom date. Is an awkward Instagram picture just today’s equivalent, or does the fact that that the photo can be revisited again and again, by potentially hundreds or even millions of eyes, change things?
There’s a growing amount of scholarship on this issue and the results are somewhat comforting: Most kids aren’t opposed to parents sharing pictures of them, but like most human beings, they would like their feelings to be considered. “Ask your kids’ permission, at least sometimes,” says Sarita Schoenebeck, an expert on how families use technology at the University of Michigan in Ann Arbor. “Pay attention to what they do and don’t like and respect that.”

Schoenebeck and her colleagues recently surveyed 331 parent-child pairs to examine both parents’ and children’s preferences about what’s fair game to share on social media. Overall, the kids, who ranged in age from 10 to 17, didn’t mind when parents posted “positive” content, Schoenebeck’s team reported. Kid-approved posts included pictures showing them engaged in hobbies like sports, or depicting a happy family moment. Embarrassing pictures, on the other hand, were not appreciated. (No “naked butt baby pictures,” said one kid). The team reported its findings in 2017 at the Association for Computing Machinery’s Conference on Human Factors in Computing Systems in Denver.

Kids also expressed being aware of their own privacy in ways adults often don’t give them credit for. Photos with potential boyfriends or girlfriends were not acceptable. Content deemed too candid (such as “what they are really like at home” and “private stuff”) was also off-limits.

This self-awareness was reassuring to me. Much of being a kid is playing literal and figurative dress-up; it’s figuring out what’s OK and not OK, personally, as a family member and as a citizen of the world. I’ve worried that today’s online ecosystem might quash the freedom to do this important experimentation. Kids seem to be tuned into this dilemma too.
Most parents thought they should probably ask their kid’s permission before posting more often. Indeed, they were right: The kids thought parents should ask for permission more often than they do. Previous work by Schoenebeck is in line with that sentiment: Children were twice as likely as parents to report that adults shouldn’t “overshare” by posting about children online without permission.

The issue of kid privacy extends beyond posting pictures, notes computer security and privacy expert Franziska Roesner. “Until what age do you track location on their phone, or even use the camera function on a baby monitor?” says Roesner, of the University of Washington in Seattle. “It’s an evolving space without clear answers.”

It’s too early to say how kids growing up in the current technology climate will feel about their parents’ sharing in hindsight. But a small study by Schoenebeck offers some insight. The researchers asked college students to reflect on their own potentially embarrassing teenage Facebook posts. The students valued the authenticity of their own historical content even if it was potentially embarrassing, Schoenebeck says. As one study participant put it: “When I look at [my old content], it’s kind of like ugh, like ‘yikes!’ [But] if someone finds it I’ll just be like, ‘yeah, I had a thing with song lyrics as my status when I was 15 years old. Get over it.’”

But just because kids didn’t mind their teenage posts surviving online, that doesn’t mean they won’t mind what you post about them. My daughter isn’t old enough yet to say, “You’re not the boss of me.” But I know that time is coming. Before that happens, I plan to start asking her permission about what I post about her and give her the option of deleting old posts.

Given the myriad other concerns parents have about kids and social media — from bullying to body image issues to what potential employers or colleges might see — asking our kids’ permission about what we share seems like an easy, thoughtful step to take.

Laura Sanders is away on maternity leave. Rachel Ehrenberg is a Boston-based science journalist and former reporter at Science News, with degrees in botany and evolutionary biology. She has raised many plants and is now trying to raise a human being.

Cracks open in the ground. Lava creeps across roads, swallowing cars and homes. Fountains of molten rock shoot up to 70 meters high, catching treetops on fire.

After a month of rumbling warning signs, Kilauea, Hawaii’s most active volcano, began a new phase of eruption last week. The volcano spewed clouds of steam and ash into the air on May 3, and lava gushed through several new rifts on the volcano’s eastern slope. Threatened by clouds of toxic sulfur dioxide–laden gas that also burst from the rifts, about 1,700 residents of a housing subdivision called Leilani Estates were forced to flee their homes, which sat directly in the path of the encroaching lava.
The event marks the 62nd eruption episode along Kilauea’s eastern flank, which is really part of an ongoing volcanic eruption that started in 1983. The volcano is one of six that formed Hawaii’s Big Island over the past million years. Mauna Loa is the largest and most central; Kilauea, Mauna Kea, Hualalai and Kohala occupy the island’s edges. Mahukona is currently submerged. All six are shield volcanoes, with broad flanks composed of hardened lava flows.

Kilauea’s activity has now shifted to its southeast flank, which continues to steam. No new rifts have opened since May 7, but the eruption may be far from over, says Victoria Avery, a volcanologist and associate program coordinator for the U.S. Geological Survey’s Volcano Hazards Program, based in Reston, Va.
Science News talked with Avery about Kilauea’s fury, the quakes and what to expect next from the volcano. Her responses were edited for brevity and clarity.
Q: Is there anything unusual about this eruption?

A: Not to scientists; it’s typical of what Kilauea volcano can do.

Q: Were there any warning signs?

A: We saw shallow earthquake activity under [the eastern flank of Kilauea] for several days. That tells us that molten rock is moving underground. We also saw that the lava lake at the summit of Kilauea was lowering; there’s a vent called Pu’u ‘O’o [which has erupted nearly continuously since 1983], and the floor [beneath its magma reservoir] collapsed on April 30. That told us that magma is being withdrawn and moved elsewhere. That collapse, plus the new seismicity, told us something was going to happen.
Q. On May 4, two large earthquakes measuring magnitude 5.4 and magnitude 6.9 shook the Big Island in quick succession. How are they related to the eruption?

A: It’s not frequent but not unusual for Hawaii to have earthquake[s] like that, because a volcano is a very dynamic place. The [surface swelling] associated with the eruption probably triggered the quake[s]: The magma pushed on the volcano from inside. The whole south flank of Kilauea is an area that has a history of large earthquakes. We didn’t directly anticipate it, but we weren’t that surprised when it happened.

Q: Did the people who live there know they were in a hazardous zone?

A: The eruption is right on one of the rift zones of the volcano. The fact that there was a subdivision right on top of it, I can’t comment on. But those houses are right where we know it can erupt. Right now, [emergency managers] are allowing people back in briefly to check on their homes, but not allowing them to stay.
Q: How dangerous is the gas that’s also erupting with the lava?

A: The gas is chiefly carbon dioxide and sulfur dioxide. The gas is actually what propels the [lava] to come out of the ground. Carbon dioxide in enough quantity can suffocate people. Sulfur dioxide can react with the atmosphere to create sulfuric acid. It forms “vog,” or volcanic fog, that can exacerbate asthma. That’s why they’re putting gas masks on people who go in to check on their homes.

Q: How are researchers monitoring this eruption?

A: We’re using the classic tools: instruments measuring seismicity and deformation, visual observations on the ground or flying over in helicopters, and thermal and deformation imagery from satellites. Using remote sensing, you can take [high-resolution images of ground elevation using] synthetic-aperture radar, or SAR, measurements at two different points in time to see the deformation.
Hawaii is a supersite, which means we get a lot of free SAR imagery over it, at about every two or three days. That may not be enough time for frequent eruption warnings, but it’s useful to monitor precursor activity and know what to look for. In the future, we’d like to use drones as well to monitor the eruptions.

Q: Nearby Mauna Loa is on yellow alert (to inform the aviation sector of potential ash hazards), because the volcano is showing signs of unrest. Is it at risk of erupting, too?

A: Mauna Loa really scares us. It is the largest volcano on the planet; it’s the big monster volcano of Hawaii. Kilauea has been erupting continuously since 1983, but Mauna Loa last erupted in 1984. But Mauna Loa can pump out much larger volumes and much faster. It has been yellow since September 2015, when there was elevated seismicity and deformation. It’s still a yellow, but it has quieted a bit.

Q: What’s next? Does the lull in activity at Kilauea mean the eruption is almost over?

A: It’s likely only a pause. The seismicity and deformation can wane and then build up again. The best we can do is watch precursor phenomena 24/7. [These include] the seismic data, the height of the lava lake and the deformation of the volcano along the rift zone. Where it swells, the magma is underneath it; where it goes down, the magma is withdrawing.

Q: The lava lake appears to be sinking again (as of May 6). Does that suggest more eruption is imminent?

A: It generally means that the lava is traveling down the rift zone. There’s likely more to come.

An asteroid that flouts the norms of the solar system might not be from around here.

The renegade asteroid travels around the sun in reverse — in the opposite direction of the planets and most other asteroids (SN: 5/13/17, p. 5). Now two scientists suggest that’s because the space rock originated from outside the solar system, according to a paper published May 21 in Monthly Notices of the Royal Astronomical Society Letters.

Astronomers Fathi Namouni of the Côte d’Azur Observatory in Nice, France, and Helena Morais of Universidade Estadual Paulista in Rio Claro, Brazil, used computer simulations to show that the asteroid, which shares its orbit with Jupiter, could have been traveling in reverse ever since the solar system’s youth. Because asteroids in the infant solar system formed from one swirling cloud, they should have all been traveling in the same direction. So the best explanation, the duo suggests, is that the rock, known as 2015 BZ509, migrated here from another star’s planetary system.
In 2017 astronomers spotted the first interstellar asteroid, dubbed ‘Oumuamua, which cruised through the solar system and back out again (SN Online: 12/1/17). Asteroid 2015 BZ509, however, appears to be a long-term inhabitant.
“It’s certainly an interesting possibility,” says astronomer Martin Connors of Athabasca University in Canada. But, he says, the study doesn’t nail down whether the asteroid actually came from outside the solar system.

Such asteroids are faint and hard to get information from, Connors says. “There isn’t really a blazing sign saying, ‘Hey, I’m not from here.’ ”

A space ravioli. A planetary baguette. A cosmic Kaiser roll. Some of Saturn’s moons have shapes that are strangely reminiscent of culinary concoctions.

Images of the oddball moons, mostly from the now-defunct Cassini spacecraft (SN Online: 9/15/17), got planetary scientists wondering how these satellites ended up with such strange shapes. Now, researchers suggest that collisions between young moonlets could have done the job, according to a study published online May 21 in Nature Astronomy.

Adrien Leleu , a planetary scientist at the University of Bern in Switzerland, and colleagues developed computer simulations that let the scientists virtually smack together similar-sized moonlets at various speeds and angles. The team found that, at low angles and relative speeds of tens of meters per second (roughly equal to a car on country roads), impacts can create offbeat shapes that look like the misfits around Saturn.
Head-on collisions result in a flattened moon like Pan, which resembles an empanada (SN Online: 3/10/17). An impact angle of just a few degrees leads to an elongated satellite such as Prometheus, which looks like a French loaf.
Not all run-ins create a weird looking moon. At higher angles, for example, moonlets might hit and run. Or they could form highly elongated rotating moons that subsequently break apart.
Leleu and collaborators focused on the smaller moons of Saturn that orbit within the planet’s rings. But the team also found that a similar collision between two larger moonlets could also account for the odd shape of Iapetus (SN Online: 4/21/14), a more distant walnut-shaped moon with a pronounced ridge along its equator that has puzzled scientists since the belt’s discovery. Other speculative origins for the ridge include volcanoes, plate tectonics or ring debris that rained down on the moon.