Something catapulted a pair of stars from the outer rim of our galaxy, but astronomers aren’t sure what. A binary star known as PB 3877 is rocketing away at about 2 million kilometers per hour — possibly fast enough to escape the galaxy’s gravitational pull — and all the usual explanations for such speedy stars fall short. Astrophysicist Péter Németh of the University of Erlangen-Nuremberg in Germany and colleagues report the discovery in the April 10 Astrophysical Journal Letters.
Many galactic escapees get kicked out after a close brush with the supermassive black hole in the Milky Way’s center. But PB 3877, first noticed in 2011 and currently about 18,000 light-years away in the constellation Coma Berenices, has been nowhere near that behemoth. A supernova could be responsible; it has happened before (SN Online: 3/5/15). But PB 3877 is two stars traveling together. A supernova would have torn the two apart. Németh and colleagues propose that the duo may be left over from a smashup between the Milky Way and a smaller galaxy. If that’s the case, then there might be others like PB 3877 lurking in the galactic outskirts.
On April 19, 1966, Roberta Gibb became the first woman to (unofficially) finish the Boston marathon. Women were officially allowed to enter the race in 1971, and Boston medaled its first female winner in 1972 — the year that also saw the passage of Title IX — the amendment that prohibits discrimination based on sex in education programs or any program receiving federal funding. This year, 13,751 women crossed the Boston marathon finish line, making the finisher list 45 percent female. In the last 50 years, other sports have also welcomed in women, from weightlifting to rugby to wrestling. And of course, women exercise noncompetitively, lifting weights, holding yoga poses and putting in hours on the track and in the gym.
Women are making up for a historical bias against them in sports. Not surprisingly, there’s also historically been a bias in sports science. “If you went all the way back to the 1950s, a lot of exercise physiology studies about metabolism talk about the 150-pound-man,” says Bruce Gladden, an exercise physiologist at Auburn University in Alabama and the editor in chief of the journal Medicine and Science in Sports and Exercise. “That was the average medical student.” It was a matter of convenience, studying the people nearest at hand, he explains.
Over time, athletes (and convenient student populations) have become more diverse, but diversity in studies of those athletes has continued to lag behind. When Joe Costello, an exercise physiologist at the University of Portsmouth in England, began studying the effects of extreme cold exposure on training recovery in athletes, he found that women were under-represented in the field compared to men. He wondered, he says, “is that the case across the board in sports science?”
Digging through three influential journals in the field — Medicine and Science in Sports and Exercise, the British Journal of Sports Medicine and the American Journal of Sports Medicine — Costello and his colleagues analyzed 1,382 articles published from 2011 to 2013, which added up to more than six million participants. The percentage of female participants per article was around 36 percent, and women represented 39 percent of the total participants, the scientists reported in April 2014 in the European Journal of Sport Science.
“In my opinion, it’s not enough,” he says. The numbers are relatively close to the gender breakdowns in competitive sport, he notes, but participation in noncompetitive exercise and casual running is a lot closer to a 50:50 breakdown, and the studies don’t reflect that. Despite the gap, Costello’s study did show that women are represented in exercise science studies in general. But I wondered if the trend was improving — and if the type of study mattered. Are scientists studying women in, say, studies of metabolism, but neglecting them in studies of injury? I looked at published studies in two top exercise physiology journals and found that women remain under-studied, especially when it comes to studies of performance. Reasons for this under-representation abound, from menstrual cycles to funding to simple logistics. But with recent requirements for gender parity from funding agencies, reasons are no longer excuses. When it comes to the race to fitness, women are well out of the starting blocks, but the science still has some catching up to do. Let’s look at the data I followed Costello’s lead and looked at studies published in Medicine and Science in Sports and Exercise and the American Journal of Sports Medicine, this time looking at the first five months of 2015(the former journals had articles available for free through May 2015; the latter granted me access. The third journal in the previous study, the British Journal of Sports Medicine, would only grant me access on a case-by-case basis). I excluded single case studies, animal studies, cell studies, studies involving cadavers and studies that dealt with coaches’ or doctors’ evaluations. I also excluded studies where the gender breakdown of participants wasn’t given (11 studies that included people didn’t mention the gender of the participants), and studies where there would be no reason to include women (such as those involving prostate cancer recovery).
That left me with 188 studies that included 254,813 participants. Of the 188 studies, 138, or 73 percent involved at least some women. But overall, women made up only 42 percent of participants. While 27 percent of the studies included only men, only 4 percent were studies of only women.
These results were similar to those Costello and his group showed in 2014. But I also wondered what, exactly, those women were being studied for. I took the 188 studies and divided them into six categories:
Studies on metabolism, obesity, sedentary behavior, weight loss and diabetes Studies of nonmetabolic diseases Basic physiology studies Social studies, including uses of pedometers and group exercise Sports injury Performance studies. In studies of metabolism, obesity, weight loss and diabetes (23 total studies), women were included in 87 percent of studies and represented 45 percent of participants, getting relatively close to gender parity. For nonmetabolic diseases (18 studies), 85 percent of studies included women, and they represented 44 percent of participants. Out of 188 studies, the number of studies involving women ranged from 36 percent in performance to 100 percent in social studies.
In basic physiology studies (11 total studies), including studies of knee and muscle function and studies of people in microgravity, women were included in 45 percent of studies, and represented 42 percent of all participants.
Women were represented in 100 percent of social studies (seven papers) and made up 60 percent of the participants. These included studies such as self-cognition, how well people adhere to wearing activity trackers, and the influence of meet-up groups on exercise. “Women are more likely to take part in [or] be recruited to group training programs than men,” notes Charlotte Jelleyman, an exercise physiologist at the University of Leicester in England.
The most striking differences came when studying performance and sports injury. There were 102 studies of sports injury and recovery, from concussions and elbow and shoulder repair in baseball players to studies of injury in surfers. Women were present in 80 percent of these studies, but made up 40 percent of participants.
I was especially interested in the large number of studies (38 total) on knee and ACL repair. In these studies, women were present in 94 percent of studies, but were only about 42 percent of participants. “That’s a case where you would think there would be more emphasis,” Gladden notes. “ACL injuries are much more prevalent in female athletes.” Out of more than 250,000 participants in the 188 studies analyzed, the majority were men, particularly in analyses of sports performance and injury.
But the biggest difference came in sports performance — training to get better, recover faster and perform stronger. Of 30 studies, 39 percent involved women, and women made up almost 40 percent of participants. But this result was heavily skewed by a single study of more than 90,000 participants, which examined sex differences in pacing during marathons. When this study was removed, the total number of participants in all performance studies dropped to 4,001. And the percentage of female participants dropped with it — to 3 percent. Scientists may be trying to get at the secrets of the best athletes, but to do so, they are mostly looking in men.
Time, money and menstrual cycles There are many reasons why women might be under-represented in exercise science. One is the same reason that haunts many sex disparities in biological research — the menstrual cycle.
With monthly hormone cycles, “[we] have to test [women] at certain phases,” even if you’re studying something seemingly unrelated, such as knee pain, explained Mark Tarnopololsky, a neurometabolic specialist at McMaster University, who has extensively studied sex differences in exercise. “One has to choose which phase — follicular or luteal phase — so I think when physiologists are limited in their funds, it’s easier to get guys to come in at any time.”
For some types of studies, scientists note that no previous studies have found sex differences. So scientists just study men — with no menstrual cycle to worry about — and apply the results to women. But “it’s not good enough,” says Jelleyman. “Just to say that because it works in men and previous studies have found no sex differences we assume it will work on women too – you have to show it.” Many scientists worry that cycling hormones means variable data points, so it’s easier to study men and state that the results probably apply to women, too. But that’s a cop out, says Marie Murphy, an exercise scientist at Ulster University in Northern Ireland. “If you revisit [women] in the same phase, they should be no more variable than a man,” she notes. “You return to them 28 days later and that’s easy enough. It’s not a difficult thing to do. But I think if you’re looking for an excuse you’ll find one.”
Using that excuse can mean missing important differences. Before Gibb’s Boston run in 1966, many people — including scientists — viewed distance running and extreme exercise as somehow unhealthy for women, Tarnopololsky explains. After his lab studied differences in metabolism in men and women during endurance exercise, his group found that “Women were at least as good, if not better able to withstand the rigors of the exercise.”
But menstrual cycles aside, studies are expensive, particularly studies involving people. In many cases, simplifying the study population is the only way to complete the work on time and within budget. As a member of the coaching teams associated with elite athletes, Louise Burke, a sports nutritionist at the Australian Institute of Sport, says she takes her research chances where she can find them. For a recent study of male race walkers, “when we decided to do the study I did think we’d have female race walkers,” she says. But she found that the pool of potential female participants was small. “We didn’t have a lot in Canberra,” she recalls. “Of that ones that were of the right caliber, we had people being injured, a couple who were doing a race that wouldn’t make them available.”
And when logistics shoot down one sex in a study, it will be the women who lose out. “Conference organizers are careful and include symposia on sex differences,” says John Hawley, an exercise physiologist at Australian Catholic University. But when it comes to actually doing studies, there can be challenges. Many of Hawley’s studies are invasive, involving biopsies that leave scars. And many women aren’t willing to get scarred for science. “If I go out to a triathlon and say to the females, ‘we’d like to do invasive work,’ they’re like ‘ooh, no biopsies,’” Hawley says. “It’s a legitimate practical issue.”
Finally, there are also cultural reasons that women end up underrepresented. Female athletes don’t get the same TV time as male athletes, and the players don’t get paid as much, even though, as in soccer, the women’s national team is more highly ranked than the men’s. This disparity might also result in [gender] disparity in performance studies, Gladden suggests. “Science unfortunately isn’t immune to those same problems.”
Leveling the playing field Calls for equality in exercise research continue. In a recent article in The Sport and Exercise Scientist, Murphy looked at the March issue of the Journal of Sports Sciences, and found that the 13 papers in the issue included 852 participants, but only 103 women, a dismal participation rate of only 12 percent.
While Murphy notes that other fields of study may have similar findings, exercise science needs to do better. “It’s quite simple,” she says. “If we want to apply the findings to men and women, we need to test our hypotheses and do our measures in research involving men and women.”
The lack of parity for female research participants “should be alarming,” Hawley says. He notes that while scientists bear some responsibility, “the funding bodies and editors of journals should be asking more serious questions.” Scientists who peer-review each other’s work should also ask hard questions, he says. “Peer review is failing as well….The typical responses [are] ‘unfortunately the budget does not permit females’ (a complete white lie of course), and time and practicalities. It’s not an excuse.”
As is true in many areas of science, as more women join the ranks of scientists studying exercise, they are more likely to include women in their studies. But Murphy notes that it won’t solve the problem. “I don’t think scientists think of it unless they have a particular interest in the area,” she says. “There are really good women researchers [in exercise science], but they study men, and the men study men! We’re not doing ourselves any favors.”
The broader impact of this gender imbalance is that training, fitness and diet recommendations for performance and recovery are based on science that may have only been done in men, and then downsized to fit women. Sometimes it may make no difference. But what if it could? In the end, the road to stronger, better, faster and healthier is one with studies that include everyone. “It is important to show that the general principles of exercise effectiveness are applicable to all populations whether it be males or females, older or younger, ethnically different or diseased populations,” says Jelleyman. “Sometimes it emerges that there are differences, other times less so. But it is still important to know this so that recommendations can be based on relevant evidence.”
Dogs were domesticated at least twice, a new study suggests.
Genetic analyses of a 4,800-year-old Irish dog and 59 other ancient dogs suggest that canines and humans became pals in both Europe and East Asia long before the advent of farming, researchers report June 3 in Science. Later, dogs from East Asia accompanied their human companions to Europe, where their genetic legacy trumped that of dogs already living there, the team also concludes.
That muddled genetic legacy may help explain why previous studies have indicated that dogs were domesticated from wolves only once, although evidence hasn’t been clear about whether this took place in East Asia, Central Asia or Europe. The idea that dogs came from East Asia or Central Asia is mostly based on analysis of DNA from modern dogs, while claims for European origins have been staked on studies of prehistoric pups’ genetics. “This paper combines both types of data” to give a more complete picture of canine evolution, says Mietje Germonpré, a paleontologist at the Royal Belgian Institute of Natural Sciences in Brussels, who was not part of the study.
Understanding this domestication process may illuminate humans’ distant past — dogs were probably the first domesticated animal and may have paved the way for taming other animals and plants.
In the study, evolutionary geneticist Laurent Frantz of the University of Oxford and colleagues compiled the complete set of genes, or genome, of an ancient dog found in a tomb near Newgrange, Ireland. Researchers drilled into the hard-as-stone petrous portion of the dog’s temporal bone, which contains the inner ear, to get well-protected DNA, Frantz says. The researchers don’t know much about what the midsize dog looked like; it doesn’t bear any genetic markers of particular modern dog breeds, Frantz says. “He wasn’t black. He wasn’t spotted. He wasn’t white.” Instead, the Newgrange dog was probably a mongrel with fur similar to a wolf’s.
But the ancient mutt has something special in his genes — a stretch of enigmatic DNA, says Germonpré. “This Irish dog has a component that can’t be found in recent dogs or recent wolves.” That distinct DNA could represent the genetic ancestry of indigenous European prehistoric dogs, she says. Or it could be a trace of an extinct ancient wolf that may have given rise to dogs (SN: 7/13/13, p. 14). Unraveling the prehistoric mutt’s DNA may help researchers understand dogs’ history. Already, comparisons of the ancient Irish dog’s DNA with that of modern dogs reveal that East Asian dogs are genetically different from European and Middle Eastern dogs, the researchers have found. Other researchers may have missed the distinction between the two groups because they were working with subsets of the data that Frantz and colleagues amassed. Frantz’s team generated DNA data from the Newgrange dog and other ancient dogs, but also used data from previous studies of modern dogs, including the complete genomes of 80 dogs and less-complete sampling of DNA from 605 dogs, a collection of 48 breeds and village dogs of no particular breed.
The distinct genetic profiles of today’s Eastern and Western dogs suggests that two separate branches of the canine family tree once existed. The Newgrange dog’s DNA is more like that of the Western dogs. Since the Irish dog is 4,800 years old, the Eastern and Western dogs must have formed distinct groups before then, probably between about 6,400 to 14,000 years ago. The finding suggests that dogs may have been domesticated from local wolves in two separate locations during the Stone Age.
The ancient dog’s DNA may also help pinpoint when domestication happened. Using the Newgrange dog as a calibrator and the modern dogs to determine how much dogs have changed genetically in the past 4,800 years, Frantz and colleagues determined that dogs’ mutation rate is slower than researchers have previously calculated. Then, using the slower mutation rate to calculate when dogs became distinct from wolves, the researchers found that separate branches of the canine family tree formed between 20,000 and 60,000 years ago. Many previous calculations put the split between about 13,000 and about 30,000 years ago, but the new dates are consistent with figures from a study of an ancient wolf’s DNA (SN: 6/13/15, p. 10). Frantz and colleagues emphasize that their estimate doesn’t necessarily pinpoint the time of domestication. It could indicate that different populations of wolves were evolving into new species at that time. One of those could later have evolved into the ancestor of dogs. Although the new study indicates there were two origin points for dogs, humans’ canine companions have since mixed and mingled. By comparing mitochondrial DNA, the genetic material inside energy-generating organelles, from 59 ancient European dogs and 167 modern dogs, the researchers determined that East Asian dogs at least partially genetically replaced European dogs in the distant past. Mitochondria are inherited from the mother. Ancient European dogs’ mitochondrial DNA varieties, or haplogroups, differed from those of modern dogs, the researchers found. Of the ancient dogs, 63 percent carried haplogroup C and 20 percent carried haplogroup D. But in present-day dogs, 64 percent carry haplogroup A and 22 percent carry haplogroup B. That shift and other evidence indicate that dogs from the East moved west with humans, and Eastern dogs passed more of their genetic heritage to descendants than Western dogs did.
Archaeological evidence backs up the dual origin story. Dogs as old as 12,500 years old have been found in East Asia. In Europe, dogs date back to 15,000 years ago. But there is a dearth of dog remains older than 8,000 years old in Central Eurasia. That lack possibly rules out this in-between region as a domestication site, despite some genetic evidence from village dogs that says otherwise (SN:11/28/15, p. 8). “The argument in this paper, pointing out a pattern in the archaeological data of an absence of early dog remains in the period [before] 10,000 years ago, should be taken very seriously,” says Pontus Skoglund, an evolutionary geneticist at Harvard University.
He’s not yet won over by the double-domestication hypothesis, though. The researchers admit they can’t yet rule out that dogs were domesticated once, then transported to different places where isolation, random chance and other factors caused them to drift apart genetically.
More ancient DNA may help clarify the still-hazy picture of dog domestication. Says Skoglund: “It’s going to be an exciting time going forward.”
Fire was one of our ancient ancestors’ first forays into technology. Controlled burns enabled early hominids to ward off cold, cook and better preserve game. New evidence places fire-making in Europe as early as 800,000 years ago, much earlier than previously thought and closer to scientists’ best estimate for hominids’ first use of fire, about 1 million years ago in Africa.
It’s unclear how early Homo species came to master fire, but it was perhaps an attempt at problem solving — capturing a natural phenomenon and harnessing it for use. That tradition has persisted in human cultures. It thrives today among scientists, especially those engaged in problem solving related to society’s most pressing issues. Take drug addiction, a vexing problem that has grown in urgency in the last decade as more and more people have become dependent on opioids — not only street drugs like heroin but also prescription pain meds like OxyContin and fentanyl. Opioids can be extremely difficult to give up because of their strong addictive pull. So scientists are trying to develop vaccines that would block the effects of heroin and other drugs of abuse, as Susan Gaidos reports. Eliciting a strong immune response, researchers theorize, could stop the drug from reaching the brain, preventing the high that fuels addiction. Success with such biotechnology, now being tested only in lab animals, would offer hope to many battling to stay off drugs.
Another modern scourge is terrorism, and anthropologists like Scott Atran have been exploring the psychological and cultural factors that drive some individuals to extreme acts of violence. There is no technology to prevent people from committing such acts — at least not yet. Basic explorations must always precede any practical use of new knowledge: Hominids could not use fire until they understood its nature and limits — which things burn, which do not; water and sand douse flame, oil and fat fuel it. Mapping terrorism’s contours is just a beginning on a long journey toward developing tactics for undercutting its power.
So it is with many other reports in this issue about basic explorations that may well precede the birth of new technologies. A few favorites:
A report on insights into how the microbial denizens of the gut influence weight gain and obesity. Scientists have now revealed a molecule made by microbes that sends a signal to the brain, influencing fat storage and appetite.
An intriguing study of mice with genetic mutations similar to those found in some people with autism. The findings suggest a role in the disorder for nerve cells involved with touch, as well as a new way to think about autism that may one day identify a target for novel therapies and interventions.
News of a second detection of gravitational waves from LIGO. It’s less dramatic and showy than the first black hole merger detection, announced in February. But it is nonetheless a further sign that a new era, one in which astronomers probe the heavens by watching for violent if subtle wakes in the fabric of spacetime, is upon us.
Feeling good may help the body fight germs, experiments on mice suggest. When activated, nerve cells that help signal reward also boost the mice’s immune systems, scientists report July 4 in Nature Medicine. The study links positive feelings to a supercharged immune system, results that may partially explain the placebo effect.
Scientists artificially dialed up the activity of nerve cells in the ventral tegmental area — a part of the brain thought to help dole out rewarding feelings. This activation had a big effect on the mice’s immune systems, Tamar Ben-Shaanan of Technion-Israel Institute of Technology in Haifa and colleagues found.
A day after the nerve cells in the ventral tegmental area were activated, mice were infected with E. coli bacteria. Later tests revealed that mice with artificially activated nerve cells had less E. coli in their bodies than mice without the nerve cell activation. Certain immune cells seemed to be ramped up, too. Monocytes and macrophages were more powerful E. coli killers after the nerve cell activation.
If a similar effect is found in people, the results may offer a biological explanation for how positive thinking can influence health.
The family of known dwarf planets orbiting the sun just got a new member. The tiny world, designated 2015 RR245, lives in the Kuiper belt, the icy debris field beyond Neptune that’s home to Pluto. RR245 is currently about 9.6 billion kilometers from the sun, or roughly 64 times as far as Earth, and it loops around the sun on an elongated orbit every 700 years or so.
Astronomers first noticed RR245 in February as a drifting speck of light in images taken last September at the Canada-France-Hawaii telescope in Hawaii. The planet’s size is hard to determine without knowing how reflective its surface is; it could be large and dark or tiny and bright. But if its surface is similar to other worlds in the Kuiper belt, then RR245 might be about 700 kilometers wide, just one-fifth the diameter of the moon.
Within the next couple of years, the epidemic that has battered the region since 2015 will largely be over, researchers estimate in a paper online July 14 in Science.
“If we’re not past the peak already, we’re very close to it,” says study coauthor Neil Ferguson of Imperial College London. After this outbreak winds down, it may be a decade — at least — before another large-scale Zika epidemic hits the region. The new timeline could help vaccine researchers get a jump on future outbreaks, and might make health officials rethink advice to pregnant women trying to avoid Zika-related birth defects. Ferguson’s work also suggests something counterintuitive: Current efforts to kill Zika-carrying mosquitoes might actually make it easier for the virus to reemerge.
“It’s an important and timely analysis,” says infectious disease researcher Oliver Pybus of the University of Oxford. “Policy makers would be wise to read it carefully.”
Brazil reported the first cases of Zika in May 2015. Since then, the mosquito-borne virus has spread to 48 countries. Scientists have now widely accepted Zika as a cause of microcephaly, a devastating birth defect that leaves babies with shrunken heads and brains, as well as other serious problems (SN Online: 6/28/16).
Scientists and health officials have hustled to fight Zika, but they’ve had trouble keeping up. Mosquito-control efforts haven’t helped much, says Ferguson, and a safe and effective vaccine could still be years away. What’s more, advice to postpone pregnancy isn’t always realistic, he says.
Predicting the epidemic’s course could refine current Zika-fighting strategies. Ferguson and colleagues made a computer simulation of Zika transmission within Latin America, using data from 35 countries that have reported cases. The team factored in such variables as seasonal climate variation, the ease with which Zika jumps from person to mosquito to person, and human travel patterns between countries.
After the current outbreak ends, simulations show that some 30 years could pass before Zika transmission picks up again. Once infected with Zika, people are immune to the virus, Ferguson says, capping an epidemic’s length and buying some time before a resurgence. He can’t say for sure that another major outbreak is still three decades away — but suspects a lull could last at least one decade.
Zika has “been burning through the population,” Ferguson says. “Sooner or later, it starts to run out of people to infect.”
The virus doesn’t need to infect everybody to peter out — just enough to generate herd immunity. At that point, so many people are immune to Zika that it can’t easily spread, protecting those still uninfected.
Killing mosquitoes — a strategy some countries have used to curb Zika’s reach — could actually hinder herd immunity, letting the next epidemic strike sooner, the team’s simulations suggest. With mosquito control that’s only marginally effective, a second wave of Zika hits about five years earlier than with no mosquito control at all, the simulations indicate.
“It makes sense theoretically,” says epidemiologist Mikkel Quam of Umeå University in Sweden. But considering that the cost of herd immunity might be more babies born with birth defects, he says, “any way to reduce infection is worth doing now, even if it means potentially more epidemics in years to come.”
Immunity to Zika could pose problems for vaccine development, Ferguson says. By the time researchers have something that’s safe to use, it will be hard to find a group of people to test it in. “This was a problem at the end of the Ebola epidemic as well,” he says.
Still, Ferguson says it’s an opportunity to think creatively. In the future, for instance, researchers could prequalify trial sites and get clinicians on the ground early, so when (and if) Zika hits somewhere else, say southeast Asia, they’re ready to go.
He also thinks his simulation could help health officials more clearly lay out the risks to pregnant women. Though the epidemic in Latin America will last roughly three years, his team estimates, individual outbreaks within the region can taper off after three to six months.
By tailoring recommendations to different locations, officials could limit the period of time they’re advising women to delay pregnancy.
When a honeybee colony gets hot and bothered, the crisis sets tongues wagging. Middle-aged bees stick their tongues into the mouths of their elders, launching these special drinker bees to go collect water. That’s just one detail uncovered during a new study of how a colony superorganism cools in hot weather.
Using lightbulbs to make heat waves in beehives, researchers have traced how honeybees communicate about collecting water and work together in deploying it as air-conditioning. The tests show just how important water is for protecting a colony from overheating, Thomas Seeley of Cornell University and his colleagues report online July 20 in the Journal of Experimental Biology. Water collection is an aspect of bee biology that we know little about, says insect physiologist Sue Nicolson of the University of Pretoria in South Africa. Collecting pollen and nectar have gotten more attention, perhaps because honeybees store them. Water mostly gets picked up as needed.
Bees often get as much water as they need in the nectar they sip. But they do need extra water at times, such as during overheating in the center of the nest where eggs and young are coddled. When researchers artificially heated that zone in two colonies confined in a greenhouse, worker bees fought back. They used their wings to fan hot air out of the hive. “You can put your hand in the opening of a hive on a hot day and feel the blast of air that’s being pushed out,” Seeley says. Several hundred bees also moved out of the nest to cluster in a beardlike mass nearby. Their evacuation reduces body heat within the nest and opens up passageways for greater airflow, he says.
The bees also had a Plan C — evaporative cooling. Middle-aged bees inside a hive walked toward the nest entrance to where a small number of elderly bees, less than 1 percent of the colony, hang out and wait until water is needed. Heat by itself doesn’t activate these bees, especially since they’re not in the overheating core. Seeley now proposes that the burst of middle-aged bees’ repeated begging for water by tongue extension eventually sends the water-collecting bees into action. They return carrying some 80 percent of their weight in water. “The water carrier comes in looking really fat, and the water receivers start out looking very skinny,” Seeley says. “Over a minute when the transfer takes place, their forms reverse.” Then the receiving bees go to the hot zone, regurgitate their load of water and use their tongues to spread it over the fevered surfaces.
In a water-deprivation experiment, bees prevented from gathering water could not prevent temperatures from rising dangerously, up to 44° Celsius, in their hive. When researchers permitted water-collector squadrons to tank up again, colonies could control temperatures. Even for multitalented bees, water is necessary for cooling, the researchers conclude.
After a severe heat stress, the researchers noticed some bees with plumped-up abdomens hanging inside the colony. “Sometime they would be lined up like bottles of beer in the refrigerator,” Seeley says. Bottled beverages is what they were, he argues, storing water and remaining available if the coming night proved as water-stressed as the day.
“Honeybees continue to amaze,” says Dennis vanEngelsdorp of the University of Maryland in College Park, who studies bee health. “Even after centuries of study, we have something new.”
Boeing Milestones of Flight Hall Now open After two years of renovations, some of the museum’s most cherished artifacts — including the Spirit of St. Louis and an Apollo Lunar Module — are now on display alongside new objects, including a studio model of the Starship Enterprise.
National Air & Space Museum, Washington, D.C. Pterosaurs: Flight in the Age of Dinosaurs Through October 2 Fossils, life-size models and a virtual flight lab transport visitors back to the time of these ancient fliers.
Natural History Museum of Los Angeles County DARPA: Redefining Possible Through September 5 In this hands-on exhibit, see a humanlike robot, prosthetic arm, robotic exoskeleton and other high-tech innovations developed by the U.S. Defense Advanced Research Projects Agency over the last six decades.
Like botanical vampires, dodder plants (Cuscuta sp.) suck the life out of crops around the world. But tomatoes (Solanum lycopersicum) are mysteriously immune to the parasitic vine’s attacks.
To figure out how they do it, a research team from England and Germany hit tomatoes and three other plant species with C. reflexa extract in the lab. Tomatoes totally overreacted, producing stress hormones to protect themselves from the parasite, while the other plants failed to mount a defense.
This suggests that tomatoes treat the dodder like a virus, taking cues from parasite proteins as a warning system, the team writes July 28 in Science. This sensitivity traces to a receptor that senses the presence of a small protein released by dodder plants.
This probably isn’t the only defense option. Some wild tomato species can fend off dodder even though they’re missing the gene behind the receptor, the researchers note. Still, the findings could prove useful in protecting other crops from vampiric vines through genetic engineering.
