Periodical cicadas, like the one pictured above, have missed a lot of news about insects since they last appeared. Photo via Wikimedia Commons

After 17 years underground, billions of cicadas are ready to emerge and see sunlight for the first time. They will blanket the East Coast until around mid-June, buzzing like jackhammers in harmony as they search for a mate. Since 1996, the periodical insects, which belong to a group called Brood II, have lived as nymphs two feet deep in the soil, feeding on nothing but the liquid they suck out of tree roots. Once they crawl up to the surface, they molt, mate, lay eggs and die within a month.

Scientists are still trying to determine how periodical cicadas know when to emerge. But in the last 17 years, researchers have made some other important discoveries about other insects, some of whom also enjoy swarming the United States. Here are 17 news items about the bugs’ brethren since 1996.

1. British researchers figured out how insects fly. In 1996, scientists at the University of Cambridge solved the mystery of how many winged insects can produce more lift than can be explained by aerodynamic properties. The team unleashed hawkmoths into a wind tunnel with smoke and then took high-speed photos of the insects in flight. By studying how the smoke moved around the moths’ wings, researchers were able to determine that flying insects create whirling spirals of air above the front edges of their wings, providing more lift.

2. Cuba claimed that the United States brought an insect infestation to the island. In 1997, Cuban authorities accused the U.S. of staging a biological attack the previous year by using a crop-duster to spread insects over the island. But what really happened? An American commercial airliner had flown over the country and released smoke to signal its location, an event that coincided with bug infestations on Cuba’s potato plantations.

3. A plague of crickets ravaged the Midwest. In 2001, hordes of crickets descended upon Utah, infesting more than 1.5 million acres in 18 of the state’s 29 counties. The damaged wreaked on the ironically named Beehive State’s crops totaled nearly $25 million. Michael O. Leavitt, Utah’s governor at the time, declared the infestation an emergency and sought help from the U.S. Department of Agriculture in combating the little critters.

4. Scientists uncovered an entire new order of insects. In 2002, entomologists discovered a group of inch-long wingless creatures that comprised a new order, a taxonomic rank used in the classification of organisms. The first to be identified in 88 years at that time, the order, dubbed Mantophasmatodea, consists of insects with features similar to praying mantises. The finding became the 31st known insect order.

5. A swarm of butterflies, thought to be one single species, turned out to be 10 of them. In 2004, researchers used DNA barcoding technology to study the Astraptes fulgerator butterfly, whose habitat ranges from Texas to northern Argentina. What they found was remarkable: an insect that was thought to be one species was actually 10 different species. The species’ habitats overlapped, but the butterflies never bred with its doppelganger neighbors.

6. Researchers pinpointed the world’s oldest known insect fossil. Until 2004, a 400 million-year-old set of tiny insect jaws—originally found in a block of chert along with a well-preserved and well-studied fossil springtail—lay untouched for almost a century in a drawer at the Natural History Museum in London. The rediscovery and subsequent study of the specimen meant that true insects appeared 10 million to 20 million years earlier than once thought. The researchers believe these ancient insects were capable of flight, which would mean the tiny creatures took to the skies 170 millions years ago, before flying dinosaurs.

7. Brood X invaded the East Coast. In 2004, another group of cicadas known as Brood X emerged after 17 years underground. The bugs’ motto? Strength in numbers. This class is the largest of the periodical insects, including three different species of cicada.

8. America’s bee population started to plummet. By spring of 2007, more than a quarter of the country’s 2.4 million honeybee colonies had mysteriously vanished. Something prevented the bees from returning to their hives, and scientists weren’t sure why, but they gave it a name: colony-collapse disorder. According to a recent report by the U.S. Department of Agriculture, the phenomenon continues to plague apiaries across the country, and no cause has been determined.

9. Gypsy moths destroyed thousands of trees in New Jersey. In 2007, gypsy moths ravaged more than 320,000 acres of forest in the Garden State. One of North America’s most devastating forest pests, the insect feeds on the leaves of trees, stripping branches bare. Agricultural officials said the infestation was the worst of its kind since 1990.

10. Scientists figured out how to extract DNA from preserved insect specimens. In 2009, researchers removed a barrier from the study of early insects, a practice that often left ancient specimens destroyed. In the past, too much tinkering around with tiny specimens meant that the samples often became contaminated or eventually deteriorated. The scientists soaked nearly 200-year-old preserved beetles in a special solution for 16 hours, a process that allowed them to then carefully extract DNA from the bugs without damaging them.

11. Hundreds of ancient insect species were found lodged in one chunk of amber. In 2010, a team of international researchers discovered 700 new species of prehistoric insects inside a block of 50-million-year-old amber in India. The finding signaled to scientists that the area was much more biologically diverse than previously thought.

12. The first truly amphibious insects were discovered. In 2011, a study reported that 11 species of caterpillar with the ability to live underwater indefinitely were found in freshwater streams in Hawaii. The twist? The same insects studied were land-dwellers too.

13. Scientists discovered a cockroach with more than just a spring in its step. In 2011, a new species of cockroach, for whom jumping and hopping accounts for 71 percent of movement, was found in South Africa. Saltoblattella montistabularis can cover a distance 50 times its body length with each hop. Dubbed the leaproach, the insect relies on its powerful hind legs, which are twice the length of its other limbs and make up 10 percent of its body weight, to propel it forward in high-speed bursts.

14. Japanese scientists documented radiation-induced mutations in butterflies. When a massive earthquake and tsunami severely damaged the Fukushima nuclear power plant in 2011, dangerous radioactive materials were spewed into the air and waterways. The following year, Japanese researchers said they observed dented eyes and stunted wings in local butterflies, mutations they believe were a result of radiation exposure.

15. The East Coast suffered a stink bug epidemic. In the summer of 2011, growing numbers of stink bugs prompted the Environmental Protection Agency to issue an emergency ruling that would allow farmers to use lethal insecticides. The insects had invaded crops of apples, cherries, pears and peaches from Virginia to New Jersey.

16. The world’s largest insect was discovered in New Zealand. Scientist Mark Moffett, known as Doctor Bugs, discovered the world’s largest insect, a surprisingly friendly female Weta bug, while traveling in New Zealand in 2011. The massive creature has a wingspan of seven inches and weighs three times as much as a mouse. Here’s a video of the bug eating a carrot out of Moffett’s hand.

17. A fly found in Thailand was determined to be the smallest in the world. Discovered in 2012, the fly, named Euryplatea nanaknihali, is 15 times smaller than a house fly and tinier than a grain of salt. But don’t let the miniature bugs fool you: they feed on tiny ants by burrowing into the larger insects’ head casings, eventually decapitating them.

Thousands of Dutch fans celebrate a soccer match between Netherlands and Germany in the Ukranian city of Kharkiv in 2012. The fans and their German counterparts likely share hundreds of genetic ancestors from the past thousand years. Photo courtesy of Flickr user Aleksandr Osipov

Last month, a trio of engineers debuted an app that allows Icelanders to determine if they’re actually related to a potential date. Why, you ask? Because the entire population of Iceland, roughly 320,000 people, derives from a single family tree, and it’s very possible to bump into a former flame at a family gathering.

The case of Iceland is an extreme one, but the idea that we are all distant cousins, in the scope of human history, is well accepted. A new study, published today in the journal PLOS Biology, explains this degree of relatedness in modern-day Europeans.

The study reveals that just about any two random people from anywhere in Europe, even those living on opposite sides of the continent, share hundreds of genetic ancestors from only 1,000 years ago. In fact, a person living in the United Kingdom shares a chunk of genomic material with someone living in Turkey 20 percent of the time.

Researchers from the University of California, Davis and the University of Southern California studied genomic data for 2,257 Europeans from a massive database of genome-mapped individuals known as the Population Reference Sample. They measured ancestral ties going back 3,000 years by analyzing long segments of genome, passed down from generation to generation, shared by individuals.

Distant relatives share these long blocks of genome because they have both inherited them from common ancestors. First cousins share about one-fourth of their genome, inherited from a shared set of grandparents. Second cousins share just one-sixteenth of their genome, thanks to the same pair of great-grandparents. The researchers detected 1.9 million of these shared DNA sequences within the data pool, and then used their varying lengths to infer how long ago the shared ancestors lived.

These shared chunks of genome become shorter and shorter between more distant relatives because DNA strands undergo recombination, shuffling our genetic makeup around, with each successive generation. For example, a shared block of genome is shorter between second cousins than it is between first cousins. The longer a shared segment, the more recent the common ancestor.

As we might expect, the numbers of shared genetic ancestors dramatically decrease as geographic distance (in this case, across Europe) increases. This means that people who live near each other are more likely to be related to each other than those who don’t. For example, someone living in England will have a higher degree of relatedness to a fellow Briton than he would with someone from Germany. Researchers found that two modern Europeans living in neighboring populations, for example two adjacent countries, share between two and 12 genetic ancestors from the last 1,500 years.

This pattern can be seen in historically small or more isolated populations too, where fewer possible ancestors exist. Such is the case on the Italian and Iberian peninsulas—areas least affected by Slavic and Hunnic migrations between the fourth and eighth centuries—where people share more ancestors with each other than people in most other regions of Europe. Additionally, those living in Western Europe are also somewhat less related to each other than people living in Eastern Europe, a historically tight-knit region in terms of population.

However, some findings deviate from this genealogical norm. The researchers found that people from the United Kingdom shared more recent ancestors with people living in Ireland than with other UK residents. Recent ancestry also tied Germans more closely with Polish people than with other Germans. These instances likely reflect human migration in recent centuries, as smaller populations moved into larger ones.

Although this study looked only at European lineage, the researchers suggest that such patterns probably exist in the rest of the world. In any case, such research in human history brings us closer to learning more about the most recent common ancestor of all modern humans, which scientists believe who, according to mathematical models, might have walked the Earth roughly as early as 3,500 years ago (PDF). This common ancestor, a product of the intermixing of once-isolated population groups, could have lived much earlier than this if remote populations managed to prevent its members from mating with far-flung explorers, but the recent paper’s finding seems to support the idea that distant populations converged relatively recently when compared to the long history of ancient humans.

The creamy sticks of color seen here are just the latest in a long history of lipsticks—historical records suggest that humans have been artificially coloring their lips since 4,000 B.C. Photo by Flickr user ookikioo

Lipstick has seen a fair share of funky ingredients in its long history of more than 6,000 years, from seaweed and beetles to modern synthetic chemicals and deer fat. In recent years, traces of lead have been found in numerous brands of the popular handbag staple, prompting some manufacturers to go the organic route. This week, more dangerous substances joined the roster.

Researchers at Berkeley’s School of Public Health at the University of California tested 32 different types of lipstick and lip gloss commonly found in the brightly lit aisles of grocery and convenience stores. They detected traces of cadmium, chromium, aluminum, manganese and other metals, which are usually found in industrial workplaces, including make-up factories. The report, published in the journal Environmental Health Perspectives, indicated that some of these metals reached potentially health-hazardous levels.

Lipstick is usually ingested little by little as wearers lick or bite their lips throughout the day. On average, the study found, lipstick-clad women consume 24 milligrams of the stuff a day. Those who reapply several times a day take in 87 milligrams.

The researchers estimated risk by comparing consumers’ daily intake of these metals through lip makeup with health guidelines. They report that an average use of some lipsticks and lip glosses results in “excessive exposure” to chromium, and frequent use can lead to overexposure to aluminum, cadmium and manganese.

Minor exposure to cadmium, which is used in batteries, can result in flu-like symptoms such as fever, chills and achy muscles. In the worst cases, the metal is linked to cancer, attacking the cardiovascular, respiratory and other systems in the body. Chromium is a carcinogen linked to stomach ulcers and lung cancer, and aluminum can be toxic to the lungs. Long-term exposure to manganese in high doses is associated with problems in the nervous system. There are no safe levels of chromium, and federal labor regulations require industrial workers to limit exposure to the metal in the workplace. We naturally inhale tiny levels of aluminum present in the air, and many FDA-approved antacids contain the metal in safe levels.

Despite the presence of these metals in lipstick, there’s no need to start abandoning lipstick altogether—rather, the authors call for more oversight when it comes to cosmetics, for which there are no industry standards regulating their metal content if produced in the United States. 

After all, cadmium and other metals aren’t an intended ingredient in lipstick—they’re considered a contaminant. They seep into lipstick when the machinery or dyes used to create the product contain the metals themselves. This means trace amounts are not listed on the tiny stickers on lipstick tubes, so there’s no way to know which brands might be contaminated.

Concern about metals in cosmetics came to the forefront of American media in 2007, when an analysis of 33 popular brands of lipstick by the Campaign for Safe Cosmetics showed that 61 percent of them contained lead. The report eventually led the Food and Drug Administration (FDA), which doesn’t regulate cosmetics, to look into the issue, and what it found wasn’t any better: it found lead in all of the samples tested, with levels four times higher than the earlier study, ranging from 0.09 parts per million to 3.06 parts per million. According to the Centers for Disease Control and Prevention, there is no safe level of lead for humans.

So we’ve got cadmium, chromium, aluminum, manganese and lead in our lipstick. What else? Today, most lipstick is made with beeswax, which creates a base for pigments, and castor oil, which gives it a shiny, waxy quality. Beeswax has been the base for lipstick for at least 400 years–England’s Queen Elizabeth I popularized a deep lip rouge derived from beeswax and plants.

Lipstick as we know it appeared in 1884 in Paris, wrapped in silk paper and made from beeswax, castor oil and deer tallow, the solid rendered fat of the animal. At the time, lipstick was often colored using carmine dye. The dye combined aluminum and carminic acid, a chemical produced by cochineals–tiny cacti-dwelling insects–to ward off other insect predators.

That early lipstick wasn’t the first attempt at using insects or to stain women’s mouths. Cleopatra’s recipe for homemade lipstick called for red pigments drawn out from mashed-up beetles and ants.

But really, any natural substance with color was fair game for cosmetics, regardless of its health effects: Historians believe women first starting coloring their lips in ancient Mesopotamia, dotting them with dust from crushed semi-precious jewels—these lovely ancients were eating tiny bits of rocks whenever they licked their lips. Ancient Egyptians used lip color too, mixing seaweed, iodine and bromine mannite, a highly toxic plant-derived chemical that sickened its users.

From mannite to heavy metals, humanity’s quest for painted beauty doesn’t seem to have progressed far from toxic roots. The sacrifices we make for fashion!

Flamingos depend on plant-derived chemical compounds to color their feathers, legs and beaks. Photo: Flickr user longhorndave

Pop quiz: Why are flamingos pink?

If you answered that it’s because of what they eat—namely shrimp—you’re right. But there’s more to the story than you might think.

Animals naturally synthesize a pigment called melanin, which determines the color of their eyes, fur (or feathers) and skin. Pigments are chemical compounds that create color in animals by absorbing certain wavelengths of light while reflecting others. Many animals can’t create pigments other than melanin on their own. Plant life, on the other hand, can produce a variety of them, and if a large quantity is ingested, those pigments can sometimes mask the melanin produced by the animal. Thus, some animals are often colored by the flowers, roots, seeds and fruits they consume

Flamingos are born with gray plumage. They get their rosy hue pink by ingesting a type of organic pigment called a carotenoid. They obtain this through their main food source, brine shrimp, which feast on microscopic algae that naturally produce carotenoids. Enzymes in the flamingos’ liver break down the compounds into pink and orange pigment molecules, which are then deposited into the birds’ feathers, legs and beaks. If flamingos didn’t feed on brine shrimp, their blushing plumage would eventually fade.

In captivity, the birds’ diets are supplemented with carotenoids such as beta-carotene and and canthaxanthin. Beta-carotene, responsible for the orange of carrots, pumpkins and sweet potatoes, is converted in the body to vitamin A. Canthaxanthin is responsible for the color of apples, peaches, strawberries and many flowers.

Shrimp can’t produce these compounds either, so they too depend on their diet to color their tiny bodies. Flamingos, though, are arguably the best-known examples of animals dyed by what they eat. What others species get pigment from their food? Here’s a quick list:

Northern cardinals and yellow goldfinches: When these birds consume berries from the dogwood tree, they metabolize carotenoids found inside the seeds of the fruit. The red, orange and yellow pigments contribute to the birds’ vibrant red and gold plumage, which would fade in intensity with each molt if cardinals were fed a carotenoid-free diet.

Salmon: Wild salmon consume small fish and crustaceans that feed on carotenoid-producing algae, accumulating enough of the chemical compounds to turn pink. Farmed salmon are fed color additives to achieve a deeper shades of red and pink.

Nudibranchs: These shell-less mollusks absorb the pigments of their food sources into their normally white bodies, reflecting the bright colors of sponges and cnidarians, which include jellyfish and corals.

Canaries: The birds’ normal diet doesn’t alter the color of its yellow feathers, but they can turn a deep orange if they regularly consume paprika, cayenne or red pepper. These spices each contain multiple carotenoids responsible for creating and red and yellow.

Ghost ants: There’s not much more than meets the eye with ghost ants: these tropical insects get their name from their transparent abdomens. Feed them water mixed with food coloring and watch their tiny, translucent lower halves fill up with brilliantly colored liquid.

Ghost ants sip sugar water with food coloring, which is visible in their transparent abdomens. Photo by Mohamed Babu/Solent News/Rex F/AP Images

Humans: Believe it or not, if a person eats large quantities of carrots, pumpkin or anything else with tons of carotenoids, his or her skin will turn yellow-orange. In fact, the help book Baby 411 includes this question and answer:

Q: My six-month-old started solids and now his skin is turning yellow. HELP!

A: You are what you eat! Babies are often first introduced to a series of yellow vegetables (carrots, squash, sweet potatoes). All these vegetables are rich in vitamin A (carotene). This vitamin has a pigment that can collect harmlessly on the skin, producing a condition called carotinemia.

How to tell that yellow-orange skin isn’t an indication of  jaundice? The National Institutes of Health explain that “If the whites of your eyes are not yellow, you may not have jaundice.”

More than 1 billion cases of the common cold occur in the United States each year. Credit: Flickr user mcfarlandomo

This year, prolonged extreme temperatures and seemingly never-ending snowstorms in the United States forced many inside, seeking shelter from what felt like an unusually long winter. This meant some of us were stuck in bed for a day or two clutching a box of Kleenex and downing cough syrup. That’s because viruses that cause the common cold love enclosed spaces with lots of people—the family room, the office, the gym.

And though spring has arrived, cold-causing microbes haven’t slowed down. More than 200 viruses can trigger a runny nose, sore throat, sneezing and coughing—more than 1 billion cases of the common cold occur in the United States each year. The worst offenders (and the most common), known as human rhinoviruses, are most active in spring, summer and early fall.

While it’s difficult to pinpoint exactly when infected people cease to be contagious, they’re most likely to spread their cold when symptoms are at their worst, explains Dr. Teresa Hauguel of the National Institute of Allergy and Infectious Diseases. However, there’s another window of opportunity to be wary about. “A person can be infected before they actually develop symptoms, so they can be spreading it without even realizing it if they’re around people,” Hauguel writes in an email.

Surprised? Here are five more facts about the common cold.

Cold-causing viruses can be found in all corners of the world. Rhinoviruses (from the Greek word rhin, meaning “nose”) evolved from enteroviruses, which cause minor infections throughout the human body. They have been identified even in remote areas inside the Amazon. But it’s impossible to tell how long humans have been battling colds. Scientists can’t pinpoint when rhinoviruses evolved: they mutate too quickly and don’t leave a footprint behind in preserved human fossils. They could have been infecting mankindhominids before our species appeared. Or they might have sprung up as small groups of humans moved out of isolation and into agricultural communities, where the pathogen became highly adapted to infecting them.

Cold-causing microbes can survive for up to two days outside of the body. Rhinoviruses, which cause 30 to 50 percent of colds, usually live for three hours on your skin or any touchable surface, but can sometimes survive for up to 48 hours. The list of touchable surfaces is a lengthy one: door knobs, computer keyboards, kitchen counters, elevator buttons, light switches, shopping carts, toilet paper rolls—the things we come in contact with on a regular basis. The number of microbes that can grow on these surfaces varies, but each spot can contain several different types of microbes.

You can calculate how far away to stand from someone who’s sick. When a sick person coughs, sneezes or talks, they expel virus-containing droplets into the air. These respiratory droplets can travel up to six feet to another person. A recent study found that the largest visible distance over which a sneeze travels is 0.6 meters, which is almost two feet. It did so at 4.5 meters per second, about 15 feet per second. A breath travels the same distance but much slower, at 1.4 meters—4.5 feet—per second. Moral of the story: remain six feet from infected people, and move quickly when they gear up to sneeze.

The weather plays a role in when and how we get sick—but not in the way you might think. Humidity levels can help those droplets whiz through the air quicker: the lower the humidity, the more moisture evaporates from the droplet, shrinking it in size so it can stay airborne for larger distances. Cold weather is notoriously dry, which explains why we’re more likely to catch a cold while we huddle up inside when temperatures start sinking. This type of air can dry out the mucus lining in our nasal passages; without this protective barrier that traps microbes before they enter the body, we’re more vulnerable to infection. So we’re weakened by the air we breathe in when it’s chilly out, not the chilly weather itself.

Contrary to popular belief, stocking up on vitamin C won’t help. Linus Pauling, a Nobel Prize-winning chemist, popularized the idea of taking high doses of vitamin C to ward off colds. But when put to the test, this cold remedy doesn’t actually work. If you take at least 0.2 grams of vitamin C every day, you’re not likely to have any fewer colds, but you may have colds that are a day or two shorter. When symptoms start to appear, drizzling packets of Emergen-C into glass after glass of water won’t help either. The vitamin is no more effective than a placebo at reducing how long we suffer from cold symptoms.

What can’t a 3D printer build? The number of possible answers to this question has shrunk exponentially in recent years, as the high-tech machines continue to churn out solid object after object from computer designs.

The last few months alone saw countless new products and prototypes spanning an array of industries, from football cleats and pens to steel rocket parts and guns. Last month, the technology helped replace 75 percent of a person’s damaged skull, and this week it restored a man’s face after he lost half of it to cancer four years ago.

Today, a new study suggests 3D-printed material could one day mimic the behavior of cells in human tissue. Graduate student Gabriel Villar and his colleagues at the University of Oxford developed tiny solids that behave as biological tissue would. The delicate material physically resembles brain and fat tissue, and has the consistency of soft rubber.

To create this material, a specially designed 3D printing machine followed a computer programmed diagram and ejected tens of thousands of individual droplets according to a specified three-dimensional network. As seen in the video above, its nozzles moved in various angles to establish the position of each tiny bead. Each droplet weighs in at about one picoliter—that’s one trillionth of a liter—a unit used to measure the size of droplets of inkjet printers, whose nozzle technology works much the same way to consolidate tiny dots of liquid into complete images and words on paper.

The droplets of liquid contained biochemicals found in tissue cells. Coated in lipids—fats and oils—the tiny aqueous compartments stuck together, forming a cohesive and self-supporting shape, with each bead partitioned by a thin, single membrane similar to the lipid bilayers that protect our cells.

Several 3D-printed droplet networks. Image courtesy of Gabriel Villar, Alexander D. Graham and Hagan Bayley (University of Oxford)

The shapes that the printed droplets formed remained stable for several weeks. If researchers shook the material slightly, droplets could become displaced, but only temporarily. The engineered tissue quickly sprung back into its original shape, a level of elasticity the researchers say is comparable to soft tissue cells in humans. The intricate latticework of a network’s lipid bilayers appeared to hold the “cells” together.

In some of the droplet networks, the 3D printer built pores into the lipid membrane. The holes mimicked protein channels inside the barriers that protect real cells, filtering molecules important for cell function in and out. The researchers injected into the pores a type of molecule important for cell-to-cell communication, one that delivers signals to numerous cells so that they function together as a group. While the 3D-printed material couldn’t exactly replicate how cells propagate signals, researchers say the movement of the molecule through defined pathways resembled the electrical communication of neurons in brain tissue

Water readily permeated the network’s membranes, even when pores were not built into its structure. The droplets swelled and shrank by the process of osmosis, trying to establish equilibrium between the amount of water they contained and the amount surrounding them on the outside. The movement of water was enough to lift the droplets against gravity, pulling and folding them, imitating muscle-like activity in human tissue.

The researchers hope that these droplet networks could be programmed to release drugs following a physiological signal. Printed cells could someday also be integrated into damaged or failing tissue, providing extra scaffolding or even replacing malfunctioning cells, perhaps even supplanting some of the 1.5 million tissue transplants that take place in the United States each year. The potential seems greatest for brain tissue transplants, as medical engineers are currently trying to grow brain cells in the lab to treat progressive diseases like Huntington’s disease, which slowly destroys nerve cells.

Whether it’s growing human tissue or entire ears, 3D printing technology is in full swing in the field of medicine, and countless researchers will no doubt jump on the bandwagon in the coming years.

Researchers used miniature robots to mimic how real ants maneuver networks of their own. Credit: Simon Garnier, et al

For ants, the pheromone-laden foraging trails they leave behind are like lifelines: they direct the workers toward food hubs discovered earlier and help guide them home back to their nest.

These networks of trails can stretch for hundreds of feet, quite the achievement considering many worker ants are less than half an inch in length. One type of harvester ant can lay down a set of trails (PDF) that stretch 82 feet from the entrance of its nest. The trails of a wood ant, an insect measuring just five millimeters (that’s one-fifth of an inch), reach 656 feet, each one branching out into more pathways at up to 10 spots on each trail. The leafcutter ant can build a network that spreads for almost two and a half acres.

Ant species such as these tend to take the shortest path between their colony’s nest and a food source, following branches that stray as little as possible from the direction in which they began their journey. The forks in their network of trails, known as bifurcations, are not symmetrical and don’t branch out into angles of the same size. But do ants use a sophisticated sense of geometry to trace their path, measuring the angles of the roads before picking one?

To learn more, researchers at the New Jersey Institute of Technology (NJIT) and the Research Centre on Animal Cognition in France used miniature robots to replicate the behavior of a colony of Argentine ants on the move, reported today in the journal PLOS Computational Biology. This ant species has extremely poor eyesight and darts around at high speeds, yet it can maneuver through corridor after corridor, from home to food and vice versa.

When no obstacles are around, ants prefer to walk in a straight line without deviating from their course. People are like that too: if we were walking down a street to a restaurant that’s on the same side of the road as we are, we wouldn’t cross to the opposite sidewalk unless something was blocking our way. To imbue this sense of obstacle avoidance into the robots, researchers programmed them to avoid obstacles and follow light trails, which the researchers used as a substitute for pheromone-coated paths.

An “Alice,” a tiny robot measuring two centimeters (just less than one inch), following a trail of light using two photoreceptors. Credit: Simon Garnier, et al

The 10 tiny robots in this study, called Alices, were then tasked to navigate a maze-like environment roughly 60 to 70 times their size, from a starting point representing a nest entrance to an end point signifying a food source. Two photoreceptors, mimicking ant antennae, detected beams of light. As the robots traveled through the maze, researchers introduced a wrench in the little machines’ plans—at random points in their journey, the robots were triggered to turn, a mechanism meant to further mimic ants’ meandering gaits as they creep along their paths. These random turns rotated at angles no greater than 30 degrees, as real ants are not very efficient at physically making U-turns.

In the sped-up video below, the researchers tested the Alices’ navigation skills in a complex network, charging them with choosing the shortest route between their “nest” (on the right) to a “food source (left). Varying beams of light projected onto the maze changed the robots’ movements inside the network as their photoreceptors kicked into action.

The researchers found that, without any knowledge of the geometry of the maze, the robotic ants behaved exactly as real ants do: they made small random turns, but moved in the same general direction. When they reached a fork in the road, this led the robots to choose the path that deviated least from their initial trajectory, even though they weren’t equipped to measure any angles. When they detected a light trail, they turned to follow that path.

The researchers say this means that Argentine ants may not need to use complex cognitive processes to compute the geometry of various trails. But taking the fork in the road that leads to the shortest route to food greatly increases foraging success for an entire colony. So using pheromones with an intuitive spatial knowledge of where food may be, keeps ants on the right track; as more ants follow the path to food, pheromones become more concentrated along the path, further helping to guide ants who have yet to travel. In fact, the navigation method of choosing the correct fork in the road triples the amount of food ants bring back to their nest than if they relied on pheromones alone, says lead author Simon Garnier, a biology professor at NJIT.

“If you have only the pheromones and you don’t have this trick, you’re less efficient because you’re more likely to get the ants trapped into loops,” says Garnier, who runs the institute’s Swarm Lab, which studies insect group behavior. “So they will reinforce their path around the loop, and they’ll just get stuck in this loop and turn and turn forever.”

Such navigation may also help guide ants through underground paths that connect different parts of their nests. Replicating these natural navigation tools allows researchers to better understand the inner-workings of collective animal behavior.

Psychologist B.F. Skinner taught these pigeons to play ping-pong in 1950. Photo via Psychology Pictures

B.F Skinner, a leading 20th century psychologist who hypothesized that behavior was caused only by external factors, not by thoughts or emotions, was a controversial figure in a field that tends to attract controversial figures. In a realm of science that has given us Sigmund Freud, Carl Jung and Jean Piaget, Skinner stands out by sheer quirkiness. After all, he is the scientist who trained rats to pull levers and push buttons and taught pigeons to read and play ping-pong.

Besides Freud, Skinner is arguably the most famous psychologist of the 20th century. Today, his work is basic study in introductory psychology classes across the country. But what drives a man to teach his children’s cats to play piano and instruct his beagle on how to play hide and seek? Last year, Norwegian researchers dove into his past to figure it out. The team combed through biographies, archival material and interviews with those who knew him, then tested Skinner on a common personality scale.

They found Skinner, who would be 109 years old today, was highly conscientious, extroverted and somewhat neurotic—a trait shared by as many as 45 percent of leading scientists. The analysis revealed him to be a tireless worker, one who introduced a new approach to behavioral science by building on the theories of Ivan Pavlov and John Watson.

Skinner wasn’t interested in understanding the human mind and its mental processes—his field of study, known as behaviorism, was primarily concerned with observable actions and how they arose from environmental factors. He believed that our actions are shaped by our experience of reward and punishment, an approach that he called operant conditioning. The term “operant” refers to an animal or person “operating” on their environment to affect change while learning a new behavior.

B.F. Skinner at the Harvard psychology department, circa 1950. Photo via Wikimedia

Operant conditioning breaks down a task into increments. If you want to teach a pigeon to turn in a circle to the left, you give it a reward for any small movement it makes in that direction. Soon, the pigeon catches onto this and makes larger movements to the left, which garner more rewards, until the bird completes the full circle. Skinner believed that this type of learning even relates to language and the way we learn to speak. Children are rewarded, through their parents’ verbal encouragement and affection, for making a sound that resembles a certain word until they can actually say that word.

Skinner’s approach introduced a new term into the literature: reinforcement. Behavior that is reinforced, like a mother excitedly drawing out the sounds of “mama” as a baby coos, tends to be repeated, and behavior that’s not reinforced tends to weaken and die out. “Positive” refers to the practice of encouraging a behavior by adding to it, such as rewarding a dog with a treat, and “negative” refers to encouraging a behavior by taking something away. For example, when a driver absentmindedly continues to sit in front of a green light, the driver waiting behind them honks his car horn. The first person is reinforced for moving when the honking stops. The phenomenon of reinforcement extends beyond babies and pigeons: we’re rewarded for going to work each day with a paycheck every two weeks, and likely wouldn’t step inside the office once they were taken away.

Today, the spotlight has shifted from such behavior analysis to cognitive theories, but some of Skinner’s contributions continue to hold water, from teaching dogs to roll over to convincing kids to clean their rooms. Here are a few:

1. The Skinner box. To show how reinforcement works in a controlled environment, Skinner placed a hungry rat into a box that contained a lever. As the rat scurried around inside the box, it would accidentally press the lever, causing a food pellet to drop into the box. After several such runs, the rat quickly learned that upon entering the box, running straight toward the lever and pressing down meant receiving a tasty snack. The rat learned how to use a lever to its benefit in an unpleasant situation too: in another box that administered small electric shocks, pressing the lever caused the unpleasant zapping to stop.

2. Project Pigeon. During World War II, the military invested Skinner’s project to train pigeons to guide missiles through the skies. The psychologist used a device that emitted a clicking noise to train pigeons to peck at a small, moving point underneath a glass screen. Skinner posited that the birds, situated in front of a screen inside of a missile, would see enemy torpedoes as specks on the glass, and rapidly begin pecking at it. Their movements would then be used to steer the missile toward the enemy: Pecks at the center of the screen would direct the rocket to fly straight, while off-center pecks would cause it to tilt and change course. Skinner managed to teach one bird to peck at a spot more than 10,000 times in 45 minutes, but the prospect of pigeon-guided missiles, along with adequate funding, eventually lost luster.

3. The Air-Crib. Skinner tried to mechanize childcare through the use of this “baby box,” which maintained the temperature of a child’s environment. Humorously known as an “heir conditioner,” the crib was completely humidity- and temperate-controlled, a feature Skinner believed would keep his second daughter from getting cold at night and crying. A fan pushed air from the outside through a linen-like surface, adjusting the temperature throughout the night. The air-crib failed commercially, and although his daughter only slept inside at night, many of Skinner’s critics believed it was a cruel and experimental way to raise a child.

4. The teaching box. Skinner believed using his teaching machine to break down material bit by bit, offering rewards along the way for correct responses, could serve almost like a private tutor for students.  Material was presented in sequence, and the machine provided hints and suggestions until students verbally explained a response to a problem (Skinner didn’t believe in multiple choice answers). The device wouldn’t allow students to move on in a lesson until they understood the material, and when students got any part of it right, the machine would spit out positive feedback until they reached the solution. The teaching box didn’t stick in a school setting, but many computer-based self-instruction programs today use the same idea.

5. The Verbal Summator. An auditory version of the Rorschach inkblot test, this tool allowed participants to project subconscious thoughts through sound. Skinner quickly abandoned this endeavor as personality assessment didn’t interest him, but the technology spawned several other types of auditory perception tests.

A fossil of a prehistoric bird from the enantiornithine genus shows feathers on its hind legs—evidence of an extra pair of wings. Courtesy of Xiaoting Zheng et al/Science

Roughly 150 million years ago, birds began to evolve. The winged creatures we see in the skies today descended from a group of dinosaurs called theropods, which included tyrannosaurs, during a 54-million-year chunk of time known as the Jurassic period. Why the ability to fly evolved in some species is a difficult question to answer, but scientists agree that wings came to be because they must have been useful: they might have helped land-based animals leap into the air, or helped gliding creatures who flapped their arms produce thrust.

As researchers continue to probe the origin of flight, studies of fossils have shown that theropods–particularly coelurosaurian dinosaurs, which closely resemble modern birds—had large feathers on both their fore limbs and hind limbs. However, extensive evidence for these leg feathers didn’t exist in the earliest birds. But now, a new examination of fossils reported today in the journal Science reveals several examples of this four-winged anatomy in modern birds’ oldest common ancestors.

Modern birds have two types of feathers: vaned feathers that cover the outside of the body, and the down feathers that grow underneath them. Researchers studying the approximately 120 million-year-old fossils of 11 primitive birds from the Shandong Tianyu Museum of Natural History in China found that one type of vaned plumage, also known as pennaceous feathers, was neatly preserved in skeletal fossils of these specimens, along each creatures’ hind limbs. After this find, the researchers must have been flying high: The feathers of birds’ wings, known as flight feathers, are long, stiff and asymmetrically shaped pennaceous feathers, similar to those found in the fossils. When fanned together, pennaceous feathers form the broad surfaces of birds’ wingspans—without these surfaces, birds cannot stay aloft.

Pennaceous feathers, which are composed of many flattened barbs, existed in some winged dinosaurs. Finding them on the hind legs of early birds suggests that before birds used two wings to fly, they may have depended on four. Over millions of years, however, birds gradually lost the feathers on this extra set of wings.

The study adds to existing theories that suggest the first birds flew with four wings. Examination of a primitive bird fossil from the Archaeopteryx genus in 2004 revealed long feathers on the animal’s back and legs, which would have aided its gliding ability. Two years later, another study of the crow-sized animal, which lived about 150 million years ago, reported that the prehistoric bird’s feathers resembled those on modern birds’ flight wings.

One of the more complete skeletons examined in today’s study actually showed hind-limb pennaceous feathers along the bone of each leg. The longest feather stretched almost two inches, which is remarkable considering that the legs they covered were between one inch and two and a half inches long. In fact, specimens from a group of birds called Enantiornithes, which externally resemble modern birds, showed symmetrically paired large feathers preserved along their hind leg bones. Such feather arrangement is present in modern birds’ wings.

Researchers speculate that the second set of wings might have provided extra lift or created drag in the air. They might also have helped birds maneuver their airborne bodies.

If these hind wings indeed served a functional purpose in fight, they will earn an important place in bird evolution. Bird movement is characterized by a combination of feathered arms for flight and legs for walking on land. This study suggests that if walking legs, present in birds today, developed after these feathered hind legs, then the loss of feathers on the back legs—and thus an extra pair of wings—reflects a period of change during which the arms became specialized for flight and the legs, for locomotion.

Today, leg feathers are less well developed than wing feathers—they are usually much smaller and fluffy—and they serve as protection and insulation for the leg. These fluffy bits are sparse too—instead, the legs are covered in scales, which form only if feather growth is inhibited. Studies of modern birds show how this works. As chicks develop from embryos and grow into adults, feathered legs can be transformed into scaled legs, or vice versa, by altering how certain genes are expressed.

The recent revelation about feathers on birds’ hind legs suggest that a similar genetic, and more permanent, change might have occurred early in bird evolution, according to lead researchers. This shift triggered the loss of birds’ hind wings, pushing the creatures down an evolutionary path that would allow them to fly with just two.

Mars, photo via Pixabay

Roughly 3.5 billion years ago, Mars began to shift from a wetter, warmer climate to the dry and cold planet we see today. This period of geologic change, known as the Hesperian age, was a turbulent time. The red planet saw widespread volcanic eruptions and catastrophic flooding as melted ice rushed into wide craters, forming lakes. These natural disasters carved a network of basins into its surface called outflow channels, eroding the terrain and reshaping the landscape of the planet. The exact end of this geologic period in Mars’ history is unknown, but scientists give a rough estimate of 3 billion years ago.

Later, many of these outflow channels became covered with lava, burying evidence of Mars’ geologic history. But now, a new map of the planet’s subsurface shows for the first time what one of these buried channels looks like in three dimensions. The findings, published today in the journal Science, reconstruct the Marte Vallis, the largest of the youngest channels on Mars. Marte Vallis is located in the Elysium Planitia region, an expanse of plains along the equator and the youngest volcanic region on the planet.

To create the 3D map,  the researchers used data from Shallow Radar, a device that probes for liquid or frozen water underneath Mars’ crust. Known as SHARAD, the technology is on board NASA’s Mars Reconnaissance Orbiter spacecraft, which is currently circling the planet to study its climate. SHARAD’s orbital sounding radar works in much the same way as medical imaging scans. It sends signals to the surface, some of which automatically bounce back to the spacecraft. The signals that don’t readily bounce back can penetrate Mars’ crust and register buried structures before returning to the device. The data appears in two-dimensional cross sections, which are then pieced together to build the 3D representation. In this manner, a deeply grooved set of channels was revealed.

3D visualization of the buried Marte Vallis channels underneath the surface of Mars. Image via Smithsonian Institution/NASA/JPL-Caltech/Sapienza University of Rome/MOLA Team/USGS

The system of channels, which is somewhere between 10 million to half a billion years old, spans 60 miles in width and stretches for more than 600 miles in length. From what can be seen of Marte Vallis from the surface, the channels are similar in structure to more ancient channel systems traced to the Hesperian, but the lava that had obscured many of their features made it difficult for researchers to make accurate estimates about its depth.

The new data reveals that the scale of erosion for Marte Vallis had indeed been underestimated: the 25-mile-wide main channel is at least twice as deep than earlier approximations indicated. The map shows multiple perched channels which feed into the deeper and wider main channel. These channels once lay along a series of four islands, which floods eroded into teardrop-shaped hills.

The researchers found that the geometry of the features are similar to those of the planet’s oldest channels, which are less obscured by lava, making them easier to study. This also suggests that the Marte Vallis could have been carved entirely by water, says lead study author Gareth Morgan, a geologist at the National Air and Space Museum’s Center for Earth and Planetary Studies. In fact, most Mars scientists accept that outflow channels on Mars were carved by water. Lava also carves out tunnels through thermal erosion heating up the terrain, but Morgan says that this process is implausible for the scale of erosion at the Marte Valle channels. The speed of rushing water is also more efficient at erosion that the flow of lava, which can get stuck on rock, Morgan says. In addition, lava creates tunnels that aren’t as wide—typically only several miles across—so collapsed tunnels couldn’t account for the broad size of the channels.

Using the map, researchers were also able to pinpoint the source of the floodwater: a now buried portion of the Cerberus Fossae fracture, a series of fissures in the planet’s surface. The researchers posit that water from a reservoir deep below Mars’ surface was released by nearby tectonic or volcanic activity, and it worked quickly to form the channels. These channels would have been a short-lived affair,” Morgan says. “The fracture would have connected this groundwater to the surface. After a short duration of weeks or months, the source would have been exhausted.”

But why was water in that reservoir during a time when the rest of Mars is believed to have been dry? Water, the authors believe, could have collected in aquifers below the surface during the Hesperian. This water hypothetically could have remained stable in liquid form long after the Hesperian ended. Morgan feels that the 3D map could provide more evidence to support this hypothesis, showing that Mars was wet place in the more recent—as opposed to far ancient—past.

More than 20 similar outflow channels are spread out on the surface of the planet, extending hundreds of miles in length. The most prominent are located in the Chryse Planitia, a circular volcanic plain in the northern hemisphere of Mars. The largest, the Kasei Valles, runs for 1,500 miles along the plain.

Cataclysmic floods like the ones that shaped Mars’ channels aren’t unique to the red planet. Approximately 14,000 years ago, the largest known flood on Earth sprang from Lake Missoula, a prehistoric body of water that existed at the end of the last Ice Age in present-day Montana. The waters eroded part of the landscape of Washington state, forming the Channeled Scablands, a terrain that resembles Martian outflow channels. Marte Vallis’ main channel is estimated to be between 226 and 371 feet deep, a depth that’s comparable to the Channeled Scablands.

So if Mars’ expansive outflow channels were formed by gushing water, the question remains: Where did it all ago?

Some of it vaporized, drifted to the planet’s poles, and precipitated as ice on polar caps, Morgan says. Similar to the ones we have on Earth, the polar ends on the Red Planet are covered in miles-thick layers of ice. The water also could have pooled into shallow areas below the surface, where it also froze—in 2008, NASA’s Phoenix mission confirmed that ice exists in the porous soil that makes up much of the planet’s surface.

Another possibility, Morgan says, is that the ancient water again escaped deep underground, forming a large reservoir that awaits its chance to flood again.

Wild bees, such as this Andrena bee visiting highbush blueberry flowers, provide crucial pollination services to crops across the globe. Photo by Daniel Cariveau

Insect pollination is crucial for the healthy development of our favorite foods, from apples and avocados to cucumbers and onions. Of the 100 crop species that provide 90 percent of the global population’s food, nearly three-quarters rely on pollination by bees. The rest need beetles, flies, butterflies, birds and bats to act as pollinators. It’s a mutually beneficial system—the flowers of most crops require pollen from another plant of the same crop to produce seeds or fruits, and bees and other critters transfer pollen from one plant to the next as they drink a flower’s nectar.

The agriculture industry relies on both wild pollinators and human-managed ones like honeybees, kept and cared for in hives across the country. Concern over the latter’s gradual decline has grown in recent times, but new research shows it might be the wild pollinators we should be worrying about.

In a study of 600 fields of 41 major crops (fruits, grains and nuts) on six continents, published today in the journal Science, researchers found that wild insects pollinate these crops more effectively than honeybees that are in the care of humans. In fact, compared to bees living in apiaries, wild pollinators lead to twice as much of what’s called “fruit set”—the amount of flowers that develop into mature fruits or seeds.

Pollination is essential for the production of fruits like cherries, cranberries and blueberries. Blueberries, along with tomatoes, especially depend on buzz pollination, a process by which bees vibrate their flight muscles rapidly to unleash a visible cloud of pollen into a flower. Honeybees aren’t capable of this kind of pollination, says lead study author Lucas Garibaldi, a professor at the National University of Río Negro in Argentina. Of all pollinator-dependent crops, approximately 8 percent require buzz pollination, he says.

Pollination, then, is central to ensuring our both our food staples and our varied diet.“These ecosystem services are free, but they’re important for our survival,” Garibaldi adds. “They need to be promoted and maintained if we want to continue living on this planet.”

Another new study found that wild bee population, as well as the number of different species of the insects, has plummeted over the last 120 years. Researchers used observations of interactions between plants and their pollinators in Illinois collected at three points in time: in the late 1800s, the 1970s and the first decade of this century. Of the 109 bee species seen visiting 26 woodland plants in the 19th century, only 54 remained by 2010. Rising temperatures caused mismatches in peak bee activity, measured by visits to different plants, and flowering times, a break in the delicate balance of insect-plant relationship.

Less diversity in the wild bee population meant fewer interactions between flowers, a change that in the agricultural world could result in smaller crop yields, says lead author Laura Burkle, an ecology professor at Montana State University. This throws off global agriculture production and speeds up land conversion to compensate for the loss.

“Things have changed for the worst,” Burkle says. “There’s an incredible amount of robustness within these interaction networks of species that allow them to persist in the face of really strong environmental changes, both in temperature and land-use change.” Unfortunately, these pollinators are “getting punched from a variety of sides,” she adds.

Can honeybees substitute for our disappearing wild pollinators? Garibaldi and colleagues found that these insects couldn’t fully replace the contributions of diverse populations of pollinators for a wide range of crops on farmlands on every continent. Flooding farmland with human-managed honeybees only supplemented pollination by wild insects, even for crops such as almonds, whose orchards are stocked routinely with bees.

Human-managed hives stocked with bees, ready to aid in pollination at an almond grove. Photo by Daniel Cariveau

Several culprits are behind the continuing decline of these wild pollinators. The insects usually live in forests and grasslands, and continuing conversion of such natural habitats into farmland results in shrinking numbers and types of wild pollinators, meaning fewer flowers receive the pollen necessary for reproduction. 

Last year, many plants in the eastern U.S. flowered a month earlier than any other time in the last 161 years, a result of such unusually warm weather. Burkle says bee development doesn’t always catch up to changing flowering times in plants, which leads to more mismatches in interaction and decreased pollination services. Another study in the same year found that elevated levels of carbon dioxide, combined with the use of nitrogen-infused fertilizer, altered some plants’ lifetime development. The toxic pairing led them to produce flowers with nectar more attractive to bumblebees than usual, but caused the plants to die sooner.

The waning insect population has already taken a measurable toll on crop production, including on one very near and dear to our hearts: coffee. A 2004 study of coffee pollination in Costa Rica found that when numbers of human-introduced honeybees shrunk in a given forest area, diverse pollinators native to the area, such as stingless bees known as meliponines native to the area, helped compensate for the loss. But these insects couldn’t survive at the edges of the forest like honeybees could, so the production of coffee, a crop highly dependent on pollination, eventually plummeted.

“This study supports the theoretical prediction that having many different species, which each respond to the environment in slightly different ways, is like having a stock portfolio from many different companies, rather than investing all your money in a single company’s stock,” explains Jason Tylianakis, a terrestrial ecology professor at the University of Canterbury in New Zealand. Tylianakis discussed the implications of Science’s two new studies in a paper also published today. “We should expect this kind of ‘insurance effect’ to become less common as more native pollinators go extinct.”

Given the mounting evidence, Tylianakis writes in an email that concerns about a global pollination crisis are not overstated. A changing climate, the rapid spread of farmland and a reliance on pesticides means diverse, wild pollinators will continue to face challenges as this century unfolds. If pollinators are dying out worldwide—and if pace of this die out continues with the variety of species getting cut in half each century, leaving behind less effective substitutes—food production as we know it could start to crumble.

“The bottom line is that we need biodiversity for our survival, and we can’t simply replace the services provided by nature with a few hand-picked species like the honeybee,” he says.

The human heart. Illustration by Patrick J. Lynch

It seems like science fiction, but researchers have actually grown organs from stem cells, organs that were successfully transplanted into humans. Two years ago, a man received a new trachea to replace his, damaged by cancer—the trachea was made by Swedish researchers who infused a synthetic scaffold with the patient’s own stem cells. Earlier, in 2006, scientists at Wake Forest used stem cells to successfully implant laboratory-grown bladders in young patients with spina bifida, a developmental birth defect.

Now, science has set its sights on even bigger lab-grown organs: hearts. Researchers are currently growing them in labs using scaffolds made of biomaterial which guide stem cells into becoming cardiomyocytes, the contracting cells that are basis of cardiac muscle.

Such stem cell research in humans comes with a host of ethical problems. However, a new study, published yesterday in the Journal of Clinical Investigation, suggests a different type of cell could do the job when it comes to artificially engineering new tissue. It involves a biological process that doesn’t exist in mammals: parthenogenesis

Parthenogenesis is a form of asexual reproduction that occurs naturally in plants, insects, fish, amphibians and reptiles. During this process, unfertilized eggs begin to develop as if they’ve been fertilized. For example, the entire species of marmorkrebs, a type of crayfish, is female, and the offspring produced, without any male contribution, are genetically identical to the mother.

In 2007, researchers induced human egg cells with chemicals mimicking fertilization so they would undergo the process. The result were parthenogenetic cells that share the same properties as embryos, except that they can’t grow further. The cells are akin to pluripotent stem cells derived from embryos, which means they have the ability to develop into different types of cells—including heart cells.

The German researchers in the new study used this knowledge to turn body cells of mice into parthenogenetic stem cells, which were then grown into mature, functional cardiomyocytes. Researchers used these cells to engineer myocardium–heart muscle–with the same structure and function of normal myocardium. The muscle was then grafted onto the hearts of the mice that had contributed the original eggs for parthenogenesis, where it worked the same way as existing muscle.

For humans, building heart muscle from parthenogenetic stem cell-derived cardiomyocytes in this way could overcome several hurdles, according to a new paper examining the implications of the German team’s discovery. A heart attack can destroy up to one billion cardiomyocytes. These cells can be regrown naturally by the body, but not quickly and not in significant quantities, which means tissue-engineered heart repair may become crucial for a full recovery.

Regeneration via stem cells could also mean the difference between life and death for heart transplant candidates. Approximately 3,000 people in the United States are on the waiting list for a new heart on any given day, but only 2,000 donor organs are available each year. But even if a person receives a new heart from a donor, there’s no guarantee the body will accept the new organ. A person’s immune system sees the new organ as a foreign object, which triggers a chain of events that can damage the transplanted organ. To prevent transplant rejection, patients are treated with immunosuppressive drugs, which can increase cancer risk, and most stay on at least one type of the medication for the rest of their lives. Hearts regrown from parthenogenetic stem cells, however, will likely eliminate organ rejection.

Parthenogenetic stem cells, which can be derived from cells readily made in the blood or skin, contain a genome inherited from only one individual—in this study, the mouse, and potentially in the future, a human patient. This means the cells are likely to be more compatible to the patient’s immune system—the body is less likely to reject organs grown from its own cells.

In humans, the process could remove embryonic stem cells from the equation, taking associated ethical questions with them.

What can brain scans reveal about a person’s political beliefs? Photo by Roger Ressmeyer/CORBIS

If you want to know people’s politics, tradition said to study their parents. In fact, the party affiliation of someone’s parents can predict the child’s political leanings about around 70 percent of the time.

But new research, published yesterday in the journal PLOS ONE, suggests what mom and dad think isn’t the endgame when it comes to shaping a person’s political identity. Ideological differences between partisans may reflect distinct neural processes, and they can predict who’s right and who’s left of center with 82.9 percent accuracy, outperforming the “your parents pick your party” model. It also out-predicts another neural model based on differences in brain structure, which distinguishes liberals from conservatives with 71.6 percent accuracy.

The study matched publicly available party registration records with the names of 82 American participants whose risk-taking behavior during a gambling experiment was monitored by brain scans. The researchers found that liberals and conservatives don’t differ in the risks they do or don’t take, but their brain activity does vary while they’re making decisions.

The idea that the brains of Democrats and Republicans may be hard-wired to their beliefs is not new. Previous research has shown that during MRI scans, areas linked to broad social connectedness, which involves friends and the world at large, light up in Democrats’ brains. Republicans, on the other hand, show more neural activity in parts of the brain associated with tight social connectedness, which focuses on family and country.

Other scans have shown that brain regions associated with risk and uncertainty, such as the fear-processing amygdala, differ in structure in liberals and conservatives. And different architecture means different behavior. Liberals tend to seek out novelty and uncertainty, while conservatives exhibit strong changes in attitude to threatening situations. The former are more willing to accept risk, while the latter tends to have more intense physical reactions to threatening stimuli.

Building on this, the new research shows that Democrats exhibited significantly greater activity in the left insula, a region associated with social and self-awareness, during the task. Republicans, however, showed significantly greater activity in the right amygdala, a region involved in our fight-or flight response system.

“If you went to Vegas, you won’t be able to tell who’s a Democrat or who’s a Republican, but the fact that being a Republican changes how your brain processes risk and gambling is really fascinating,” says lead researcher Darren Schreiber, a University of Exeter professor who’s currently teaching at Central European University in Budapest. “It suggests that politics alters our worldview and alters the way our brains process.”

Politics isn’t the first to cause structural changes in the brain. More than a decade ago, researchers used brain scans to show that London cab drivers’ gray matter grew larger to help them store a mental map of the city. There more time they spent on the road, the bigger their hippocampi, an area associated with navigation, became.

This implies that despite the political leanings seen through our brains, how we vote—and thus the cause of our political affiliations—may not be set in stone, Schreiber says.

“If we believe that we’re hardwired for our political views, then it’s really easy for me to discount in you in a conversation. ‘Oh, you’re just a conservative because you have a red brain,’ or ‘Oh, you’re a liberal because you have a blue brain,’” Schreiber explains. “But that’s just not the case. The brain changes. The brain is dynamic.”

Sockeye salmon rely on a magnetic map to navigate home after years spent at sea. Credit: Putman et al., Current Biology

Scientists have long known that various marine animals use the earth’s magnetic forces to navigate waters during their life cycles. Such inherent navigational skills allow animals return to the same geographic area where they were born, with some migrating thousands of miles, to produce the next generation of their species.

As hatchlings, sea turtles scuttle from their sandy birthplace to the open sea as if following an invisible map, and, as adults, the females return to that spot to lay their own eggs. Bluefin tuna home in on their natal beaches after years at sea to spawn. Similarly, mature sockeye salmon leave open water after gorging on zooplankton and krill to swim back to the freshwater streams and rivers in which they were born.

But the mechanisms underlying this behavior are not well understood for most species, including the silver-bellied salmon. Previous studies suggest that tiny variations in earth’s magnetic field might have something to do with it, but research has been mostly limited to laboratory experiments—until now.

Using fisheries data spanning 56 years, researchers examined sockeye salmon’s mysterious sense of direction in their natural habitat. The findings, reported online today in Current Biology, show that sockeye salmon “remember” magnetic values of geographic locations. They imprint their birth location on this map when they leave their freshwater home for the sea, and use it as a compass during their journey back several years later, successfully returning home to spawn.

The salmon in this study originate in British Columbia’s Fraser River. They typically spend two to four years at sea, distributed widely throughout the Gulf of Alaska. As ruby-colored adult salmon, they begin their trek home. But on their way, they encounter a roadblock: Vancouver Island, the top of a submerged mountain range that stretches for 285 miles from the Juan de Fuca Strait in the south to Queen Charlotte Straight in the north. To get back to the Fraser River, the fish have to choose—the northern inlet or the southern inlet?

If the fish did possess some internal GPS that uses earth’s magnetic field as a map, researchers expected to see the salmon’s choice of inlet change in predictable ways over the years. This is because the planet’s magnetic field doesn’t remain constant; the field’s intensity and small-scale patterns change gradually over time through a process called geomagnetic field drift, caused mainly by movement in the Earth’s fluid core.

And that’s exactly what researchers observed: salmon showed a greater preference in a given year for the inlet that most closely resembled the magnetic signature of the Fraser River when they swam from it two years earlier. Their homeward route reflected how closely the field at each entryway, at the time of their return, resembled the field that the salmon experienced two years before, when they left the river to forage at sea.

Sockeye Salmon from Fraser River in British Columbia typically spend two to four years at sea, feeding on zooplankton. Credit: Current Biology, Putman et al.

Specifically, as the difference in the magnetic field’s strength between the Fraser River and Queen Charlotte Strait decreased, a higher proportion of salmon migrated through the northern inlet. Likewise, when the difference in magnetic intensity between the river and the Strait of Juan de Fuca decreased, a higher proportion of salmon migrated through the southern inlet.

For salmon, this ability is important, and in some cases, a matter of life and death. Efficiently navigating from foraging grounds to coastal breeding areas means more time spent feeding in open water, which translates into more energy for the journey home, researchers say. The imprinting capacity also ensures salmon reach their spawning sites at the right time.

Understanding this capacity may have implications for both wild and farmed salmon, a commercially important fish. For the last decade, salmon has been the third most consumed type of seafood in the United States, behind canned tuna and shrimp, with the average American citizen chowing down on two pounds of the fish per year.

“The Earth’s magnetic field is quite weak compared to the magnetic fields that humans can produce,” said study author Nathan Putman, a professor in the fisheries and wildlife department at Oregon State University, in a statement. “If, for instance, hatchery fish are incubated in conditions with lots of electrical wires and iron pipes around that distort the magnetic field, then it is conceivable that they might be worse at navigating than their wild counterparts.”

This barred owl shares an adaptation with other owl species that allows it to rotate its head 270 degrees without damaging blood vessels in the neck. Photo via Flickr user The Rocketeer

Ever wonder how owls can turn their heads almost all the way around?

They have a complex, adaptive network of protective blood vessels that make the structures in our necks look puny–a network that researchers have now dissected, mapped and illustrated for the first time.

“Until now, brain imaging specialists like me who deal with human injuries caused by trauma to arteries in the head and neck have always been puzzled as to why rapid, twisting head movements did not leave thousands of owls lying dead on the forest floor from stroke,” said Dr. Philippe Gailloud, an interventional neuroradiologist at Johns Hopkins and a senior researcher on the study, in a statement. A poster depicting these findings won first place in the 2012 International Science and Engineering Visualization Challenge, the journal Science announced yesterday.

The carotid and vertebral arteries in the neck of most animals, including owls and humans, are delicate and fragile structures. They’re highly susceptible to minor tears and stretches of vessel linings. In humans, such injuries can be common: whiplash sustained in a car accident, a back-and-forth jarring roller coaster ride or even a chiropractic maneuver gone wrong. But they’re also dangerous. Blood vessel tears caused by sudden twisting motions produce clots that can break off, sometimes causing an embolism or stroke that could prove fatal.

Owls, on the other hand, can rotate their necks up to 270 degrees in either direction without damaging the vessels running below their heads, and they can do it without cutting off blood supply to their brains.

Researchers Philippe Gailloud (right) and Fabian de Kok-Mercado (left) examine the bone and vascular structure of an owl that died of natural causes. Photo courtesy of Johns Hopkins

Using medical illustations, CT scans and angiography, which produces X-ray images of the inside of blood vessels, researchers studied the bone structure and vascular structure in the heads and necks of a dozen snowy, barred and great horned owls after their deaths from natural causes. All three species are native to the Americas, their habitats stretching from Tierra del Fuego, the southernmost tip of the South American mainland, to the Arctic tundra of Alaska and Canada.

When researchers injected dye into the owls’ arteries to mimic blood flow and then manually turned the birds’ heads, they saw mechanisms at play that contrasted greatly with humans’ head-turning ability. Blood vessels at the base of the owls’ heads, just below the jawbone, kept expanding as more of the dye flowed in. Eventually, the fluid pooled into tiny reservoirs. Our arteries tend to get smaller during head rotations and don’t balloon in the same way.

Dye injected into deceased owls’ blood vessels pool in tiny reservoirs as their heads are rotated manually, a feature that allows for uninterrupted blood flow to the brain. Image courtesy of Johns Hopkins

Researchers believe this feature is crucial to support the top-heavy winged creatures. While they twist theirs heads back and forth, the owls’ reservoirs allow the birds to pool blood to sustain the function of their eyes and brain, which are both relatively large compared to the size of their heads. This interconnected vascular network helps minimize interruption of blood flow.

But these silent hunters’ head-on-a-swivel ability continued to be more complex, researchers found. In owls’ necks, one of the major arteries feeding the brain passes through bony holes in the birds’ vertebrae. These hollow cavities, known as the transverse foraminae, were ten times bigger in diameter than the artery passing through it. The researchers say the roomy extra space creates multiple air pockets that cushion the artery and allow it to travel safely during twisting motions.

“In humans, the vertebral artery really hugs the hollow cavities in the neck. But this is not the case in owls, whose structures are specially adapted to allow for greater arterial flexibility and movement,” said lead researcher Fabian de Kok-Mercado in the statement. De Kok-Mercado is a medical illustrator at Howard Hughes Medical Institute in Maryland.

This adaptation appeared in 12 of the 14 vertebrae in the owls’ necks. The vertebral arteries entered their necks higher up than in other birds, introduced at the 12th vertebrae (when counted from the top) instead of the 14th, which gives the vessels more slack and room to breathe. Small vessel connections between the carotid and vertebral arteries, called anastomoses, let blood flow uninterrupted to the brain, even when owls’ necks were contorted into the most extreme twists and turns.

“Our in-depth study of owl anatomy resolves one of the many interesting neurovascular medical mysteries of how owls have adapted to handle extreme head rotations,” de Kok-Mercado said.

Up next for the team is studying hawk anatomy to find out if other bird species possess owls’ adaptive features for looking far left and right.