March 26, 2012
Imagine an army of spies so tiny it could go almost anywhere undetected. The U.S. Department of Defense already has. For years their technology development arm, DARPA, has been working to create insects that will move where they’re directed. But forcing insects to go where you want them to is just half the battle. To outfit them with electronic devices—like miniature video cameras or sensors to detect poison gas, for example—you need a lightweight power source.
Last week, a team of researchers led by chemist Evgeny Katz of Clarkson University reported that they had successfully implanted biofuel cells into brown garden snails. To extract energy, the team poked electrodes through the snail’s shell into the blood-like liquid called hemolymph that lies below. The enzyme-coated electrodes harvest energy from glucose and oxygen in the hemolymph.
The snails couldn’t generate much energy, about 0.5 Volts. But Katz says the electrical energy could be stored in a condenser and then released to power an external device. In fact, that work is already underway in his lab. The next step, Katz says, is to create an organism that can power an attached micr0-sensor capable of monitoring the environment. Slow-moving snails aren’t exactly the ideal soldier, but Katz and his colleagues are also studying other organisms that might be better suited to military applications.
Other groups are working on implantable biofuel cells as well. Earlier this year, researchers successfully implanted biofuel cells in the abdomens of cockroaches, which move at a much quicker clip. And, according to Nature news, another research group accomplished the same feat in beetles.
Fuel cells aren’t the only way to get energy from small organisms. Scientists are also using piezoelectric materials, which generate current when deformed, to convert the mechanical motion of bugs’ wing beats into electricity. And in 2009, a team of scientists developed a moth fitted with a transmitter powered by radioactive isotopes. Moths have been a favorite with the Department of Defense. According to the Washington Post, in 2007 DARPA program manager Amit Lal talked about Gandalf using a moth to call for air support when he was trapped in The Lord of the Rings. “This science fiction vision is within the realm of reality,” he noted.
Last year, a team of researchers reported that they could steer a moth’s flight by attaching a neural probe to the insect’s ventral nerve cord. Check out this video of the moth in flight. Combine that technology with the power-producing biofuel cells, and the reality Lal envisions may not be so far off.
I have glimpsed the future. And it is teeming with creepy crawly cyborgs. Shudder.
March 21, 2012
The gray wolf has been taken off the federal endangered species list three separate times in the past 9 years. In each case, wolf advocacy groups persuaded courts to intervene, and the wolf ended up back on the list. On December 21, the U.S. Fish and Wildlife Service officially delisted the wolf yet again in Wisconsin, Michigan and Minnesota. And many environmentalists hope that this time the decision will stick.
Over the past several decades, the wolf population in the Great Lakes region has skyrocketed. In 1985, Wisconsin had just 14 wolves. Today the state has roughly 800. More than 4,000 wolves live in the region, most in Minnesota.
Wolves tend to steer clear of humans, so keeping track of their numbers can prove challenging. How do scientists know how many are out there? Sometimes they talk to them. In the summer and fall, they conduct howling surveys. Biologists and volunteers drive the roads at night, stopping at regular intervals to howl. At each stop, they record their location and whether they got a response from real wolves. They write down how many wolves or pups howled back. These surveys provide information on the wolves’ whereabouts, abundance and pup production. A few years ago, I accompanied expert howler Adrian Wydeven, a mammalian ecologist at the Wisconsin Department of Natural Resources.
Check out the audio clip to hear him howl like a wolf:
As the number of wolves has grown, so too has the number of wolf-human conflicts. Attacks on people are exceedingly rare, but wolves do kill dogs, cattle, sheep and other livestock, angering landowners. When the wolf was on the federal endangered species list, states couldn’t do much beyond compensating people for their losses.
The wolf’s delisting, which took effect January 27, “will make it easier to deal with problem wolves,” Wydeven says. “This allows federal trappers to trap at sites where wolves have attacked pets or livestock. It allows landowners to defend their pets and livestock.” And landownders with a history of wolf depredation problems can apply for a special permit that allows them shoot wolves on their property. Having that flexibility provides enormous comfort to landowners and “really leads to very few wolves being killed,” he says. Since the wolf came off the list, “we’ve issued almost 70 permits,” Wydeven says. So far, only one wolf has been shot by a permit holder.
Many major environmental groups are hailing the delisting as a step in the right direction. The Natural Resources Defense Council calls the delisting date, “a good day for wolves and for national wolf conservation policy.” Defenders of Wildlife and National Wildlife Federation are on board too.
But the controversy over Wisconsin’s wolves is far from over. Last week, the state assembly passed a bill that, if signed by Governor Scott Walker, would allow wolf hunting and trapping. “I’m guessing he probably will support it,” Wydeven says. The Great Lakes Indian Fish and Game Commission, a tribal resource management agency representing 11 Ojibwe tribes, opposes the bill for cultural and religious reasons.
Whether the bill passes or not, Wisconsin and neighboring states will closely monitor wolf populations in the coming years. Wydeven relies on mostly on radio collars and, in the winter, he and a team of volunteers scan the ground for wolf tracks. In the summer and fall, of course, Wydeven will continue to howl.
March 19, 2012
For millions of years, Japanese honeybees have been locked in a deadly battle with the Japanese giant hornet, a fierce predator with an appetite for bee larvae. With a two-inch-long body and a 3-inch wingspan, the hornet is enormous – many times larger than the bees. But the honeybees have evolved a unique defense mechanism: When a hornet invades a honeybee hive, as many as 500 bees gang up and form a tight ball around the attacker. The heat from the bees’ vibrating wings and the carbon dioxide they respire proves a deadly combination. In less than an hour, the hornet is dead.
The attack unfolds like this: When a hornet approaches a honeybee hive, bee guards posted at the entrance fiercely shake their abdomens. In a paper published last month, researchers argue that this abdomen shaking represents an “I see you” signal, something that is advantageous to both predator and prey. “The prey avoids attack, the predator avoids chasing a prey that has been alerted,” the researchers write. If the waggling doesn’t deter the hornet, the guards alert the rest of the hive. Some of the worker bees exit the nest and wait outside. If the hornet moves to attack, these bees surround it, forming a “hot defensive bee ball.”
A new study, published last week, examines what goes on in the honeybees’ brains while they are in this ball. The researchers, including Takeo Kubo of the University of Tokyo and Masato Ono of Tamagawa University, first identified a gene whose expression could be used as a marker of brain activity. They then used a live hornet tied to a wire to spur the formation of a bee ball. When they inserted the hornet into the hive, the bees swarmed and the researchers managed to extract the bee ball and place it in a beaker. That enabled them to pluck individual bees from the pile at different time points and examine their brains for increased expression of the target gene. (See a video of the process here.)
The balling behavior seemed to prompt activity in particular neurons found in bee brain regions called the mushroom bodies, which are involved in learning and memory. Heat exposure alone led to increased activity in these same neurons. What this means isn’t yet entirely clear. The researchers speculate these neurons may help the bees monitor how hot the ball gets and avoid overheating.
One thing is clear: The balling behavior seems vital to the bees’ survival. European honeybees, which were introduced in Japan more than a century ago, have not evolved any defense mechanisms against giant hornets. Hornet attacks can devastate their hives; a group of 20 to 30 hornets can slaughter a 30,000-bee colony in just a few hours.
March 16, 2012
As I sit down to write this post, it is 4:03 p.m. on Thursday, March 15. I’m about ready for my afternoon snack. The sun is already low in the sky. Soon, the workday will be over. I’m in Brooklyn, New York. Elsewhere, of course, it’s earlier or later, and people are doing other things. Australians might be eating breakfast or taking their morning shower. Californians are probably having lunch.
Two Johns Hopkins professors think they have come up with a more rational way to run the planet. Astrophysicist Richard Conn Henry and economist Steve Hanke argue that we should all adopt Greenwich Mean Time, also known as Universal Time. That would make it the same time everywhere, regardless of the sun’s position in the sky. So rather than writing at 4:03 p.m., I’d be writing at 20:03. Then I’d have dinner at 23:30, watch a little TV, and hit the sack around, oh, 3:00. When I awoke, it would be 11:00—not just in Brooklyn, but everywhere. “Everyone would know exactly what time it is everywhere, at every moment,” the academics write in the January issue of Globe Asia, which they say would facilitate conference calls and business transactions.
Some countries have already moved toward fewer time zones. Since 1949, China has had only a single time zone even though geographically the country spans five. In 2010, Russia abolished two of its time zones, dropping the number from 11 to nine. And Russian President Dmitry Medvedev has suggested he may prune more zones in the future. But jumping from 24 time zones to one would be a much larger leap. On some islands in the Pacific, the date would change with the sun high in the sky. People would wake up on Tuesday and go to bed on Wednesday.
Henry and Hanke also want to do away with the standard Gregorian calendar, which many countries have been using since the late 1500s. Under the new Henry-Hanke calendar, March 15—or any other day, for that matter—falls on the same day of the week, year in and year out. My birthday will always be on Wednesday. “Think about how much time and effort are expended each year in redesigning the calendar of every single organization in the world and it becomes obvious that our calendar would make life much simpler and would have noteworthy benefits,” Henry said in a press release. The pair also argue that a more logical calendar would be a boon to business. In the new calendar, every quarter has exactly the same number of days, making financial calculations simpler.
Every calendar has one major challenge that it must overcome: Each Earth year is a little more than 365 days—it lasts 365.2422 days, to be exact. The Gregorian calendar makes up for additional hours by adding a leap day at the end of February roughly every four years. The Henry-Hanke calendar adds an extra week at the end of December every five or six years. This extra week would constitute its own mini-month.
Henry and Hanke emphasize the many benefits of adopting their calendar and Universal Time, but I wonder if they’ve thought about some of the drawbacks. For example, Dolly Parton’s hit song “9 to 5” would no longer be relevant. The new office workday, at least in Brooklyn, would start at 14 and end at 22. Doesn’t have quite the same ring, does it?
March 14, 2012
Hog farmers have a lot to worry about, such as fluctuating pork prices and sick pigs. Now they have a new concern: barn explosions. The culprit appears to be a strange new foam that has begun growing on the pools of liquid manure beneath large pig farms. The foam traps methane, a flammable gas that, when ignited, can cause catastrophic blowups. One explosion last September in Iowa leveled an entire barn, killing some 1,500 pigs and injuring one worker.
On big farms in the Midwest, pigs spend the latter part of their lives in large, low buildings called finishing barns. These barns have slotted floors and sit atop eight-foot-deep concrete pits. When the pigs defecate and urinate, the waste falls between the slats and into the pit, forming an underground manure lagoon. Once a year, the farmers empty these pits and sell the manure as fertilizer. This model has been used in the Midwest for the past 30 or 40 years, says Larry Jacobson, an agricultural engineer at the University of Minnesota.
In 2009, Jacobson and other agriculture experts began to hear reports of a mysterious foam growing on swine manure ponds. “Sometimes it would be enough that it would come up through the slats,” he says. To get rid of the foam, some farmers poured water on it. Others used machines to break it up. That’s when the explosions began.
Why these explosions happen is well understood. As manure ferments, it releases methane gas, which bubbles to the surface of the pit. Normally this methane doesn’t pose a risk. The gas seeps out of the pit, and the barn’s ventilation fans carry it away. But when thick, gelatinous foam covers a manure lagoon, the methane can’t rise. The foam acts like a sponge, Jacobsen says, soaking up the gas. Jacobsen and his colleagues have collected foam samples that are 60 percent methane by volume. When a farmer disturbs the foam by agitating the manure or emptying the pit, the methane gets released all at once. In barns without adequate ventilation, the concentration of methane can quickly reach the explosive range, between 5 percent and 15 percent. A spark from a fan motor or a burning cigarette can ignite the gas. An explosion in southeastern Minnesota raised a barn roof several feet in the air and blew the hog farmer, who was on his way out, 30 or 40 feet from the door.
For the past three years, Jacobson and his colleagues at the University of Minnesota and the University of Iowa have been trying to figure out why the foam forms. The slimy stuff appears to be the byproduct of bacteria. But the researchers don’t yet know which strain or why these foam-producing bacteria suddenly appeared. The researchers are in the midst of conducting DNA analyses to try to identify the microbes, comparing foamy manure with non-foamy samples.
One explanation may be dietary changes. About five years ago, pig farmers began mixing distillers grains, a fermented byproduct of the ethanol production process, into their pig feed. Distillers grains are much cheaper than traditional feed. But that can’t be the only factor, Jacobson says. Today, nearly everyone feeds their pigs distillers grains, but only a quarter of the swine barns grow foam.
Jacobson and his colleagues have identified a few additives that seem to help eliminate the foam. But those fixes are just “band-aids” Jacobson says. What he really wants is a way to prevent the foam from forming.
Want to see what the foam looks like? Check out this YouTube video, and prepare to be disgusted.