Stories tagged Life Science

May
23
2011

Tibicen linnei: An annual cicada
Tibicen linnei: An annual cicadaCourtesy Bruce Marlin (via Wikipedia Creative Commons)
Summer is heading our way and soon the familiar buzzing of cicadas will fill the air. But for some, particularly in the southern and eastern United States, the buzz will become a loud symphony of sound. That's because, this year, the Great Southern Brood will (actually already has in some places) reappear and millions of the insects will soon be crawling out of the ground to overwhelm us with their vast numbers and cacaphonic chorus.

Relax. Last weekend's rapture was a bust (or was it?), and there’s nothing to worry about in the biblical sense. It’s merely the latest appearance of Magicicada neotredecim and M. tredecim, two closely related species of cicada that show up every 13 years in the United States to fill the treetops with their buzzing song.

The most common genus of cicadas in the US is Tibicen and unlike Magicicada, cicadas in the genus Tibicen appear annually, not periodically. After a 2-3 year stint as nymphs, Tibecen cicadas emerge into their adult stage. The full-grown insect measures about 1-2 inches in length with long translucent wings and distinctive green, brown, and black markings on the middle of its body. Generations overlap so they show up every year and can be heard in many areas, including Minnesota, during the hot and steamy Dog Days of summer buzzing to high heaven. It’s that shrill, grating noise that builds in the air and sounds like someone is cutting up cement blocks with a chainsaw. As deafening as it can be, I like the sound, in much the same way I like the smell of rotting leaves in the fall, it triggers memories.

But I’m not sure how I’d feel about Tibicen's cyclical cousins - those belonging to the Magicada genus - that show up all at once in mass periodical emergences and put on huge choruses of buzzing. There are seven species that do this in the US, three in 13-year cycles, and four in 17-year cycles. Periodical cicadas are categorized into broods numbered in Roman numerals from I to XXX. The thirteen-year cycles occupy XVIII–XXX; seventeen-year cycles number I–XVII. Only about 15 broods are still recognized. There are still only seven cyclical species but some species emerge happen at different times in different regions, hence the number of broods. This year it will be a 13-year cycle called Brood XIX , and it is the largest of the 13-year cycles in terms of geography.

The numbers involved in a periodical swarm are huge but, as Vanderbilt biologist Patrick Abbot explains, the vast numbers increase the possibility of available mates and serve as a way to overwhelm the cicadas many predators, which include birds, snakes, turtles, spiders and wasps, and even fungi. It’s interesting that the periodical emergences have evolved into separate prime number cycles. The reason is probably to reduce competition between broods.

“Say you have two populations, one which emerges every five years and one which emerges every 10 years. Then they would emerge simultaneously every 10 years," Abbot said. "Whereas the period between simultaneous emergences between populations with 13- and 17-year cycles is 221 years."

Occasionally, two cyclical broods have been known to emerge simultaneously but usually the overlap is minimal. For example two 13-year broods rising at the same time but in adjacent regions.

During a brood’s synchronized emergence the number of individuals can be daunting. Some emergences have been estimated to contain something like 1.5 million cicadas per acre of land. That amounts to 800 tons (!) of biomass busily buzzing within a square mile of forest. Think of that!

But despite the huge numbers involved in a cyclical emergence, cicadas are pretty harmless, and don’t voraciously eat up crops like locusts do, nor do they sting or bite. The most damage done is by females when they make “v”-shaped slits in the bark of a twig to lay their eggs (I suppose this could feel like a sting if she mistakes your arm for a tree branch). But, come on, even this is nothing compared to a plague of locusts wiping out the summer corn crop.

The word cicada is Latin and means “buzzer” Very apropos, don’t you think? The males of the species spend a lot of time trying to get the attention of female cicadas by vibrating a membrane on their exoskeleton called tymbals. Each time the muscles contract or relax the tymbals they produce a click. Portions of the exoskeleton such as the abdomen or thorax help amplify the sound. The rapid vibration causes a shrill and (possibly annoying) buzzing, and each of the world’s estimated 2500-3000 species has its own distinct sound. The females, by comparison, make a rather boring click with their wings to attract males (I suppose the male cicadas don’t think it boring). You can replicate the female clicking by snapping your fingers in rapid succession a couple times.

When periodical cicada eggs hatch the nymphs drop down and burrow deep into the ground where they spend most of their lives sustaining themselves for several years ingesting fluids from tree roots and developing through five juvenile stages. Scientists suspect soil temperature triggers the emergence. When it reaches 64 degrees F., the nymphs head for the surface. It seems the likely catalyst since emergences in warmer, southern regions take place sooner than those farther north. Whatever the case, when they do emerge, the nymphs crawl up and attach themselves to nearby vegetation where they eventually molt out of their skins. They don’t begin adult activities until after their exoskeletons harden. So for the first 4 to 8 days after molting, they pass through a stage called teneral (meaning soft and tender) before the exoskeleton is complete. The adult stage of a cicada lasts anywhere from a couple weeks to a few months. Very short in comparison to their other life stages.

People eat cicadas in several areas of the world. And the females are meatier and more desired. I suppose the insect is a good source of protein but – there’s no way I’m ever doing that - I’d never eat one. Maybe I shouldn’t say “never”. Some Native American tribes supposedly survived times of famine by eating cicadas.

If you live in or are visiting an area that is or will soon be overrun by an invasion of the Great Southern Brood, rather than cowering in a corner and wailing and gnashing your teeth, head outside, go for a walk, and take in a symphony of cicada songs. While you’re out there enjoying the summer day, you can get even more involved by trying some of these neat cicada experiments. It will take your mind off the fact that you’re surrounded by 800 tons of buzzing biomass.

SOURCES and LINKS

Cicada Central
Magicicada.org
Vanderbilt release
Cicada Mania page

May
14
2011

A male in New Mexico has been confirmed as being infected with the bubonic plague; and has earned the distinction of being the first person to get it this year. The Black Plague, a flea-borne disease, has never gone completely away and individuals in some remote areas are at some risk for catching it. There are about a dozen cases in the United States from bubonic plague annually.

Plague patient admitted to New Mexico hospital

The first person in the United States this year to have the bubonic plague is a 58 year old man from New Mexico. Who this man is has not been released yet. Time states it is being kept secret for now. There are certain plague symptoms. The male had them all. He was admitted with a fever, abdominal and groin pain along with painfully swollen lymph nodes. In plague patients, lymph glands swell to the point where they're visible, which in the Middle Ages came to be referred to as a "bubo," hence the name "bubonic plague.". Wikipedia explained that "bubo" means lymph nodes. It is ancient Greek.

No need to bring out the dead

On average, there are 13 bubonic plague cases annually while 1 to 40 are typically reported, the CDC states. Without treatment, 50 to 90 percent of cases will end in death. That number drops to 15 percent when treated properly. In 2003, the World Health Organization recorded 2,118 cases in nine nations and 182 deaths. Of those cases, 98.7 percent were in Africa, as were 98.9 percent of the deaths. Most cases in the United States occur in New Mexico, according to the Miami New Times. In 2009, there were 6 New Mexico plague cases. Since 1949, there have been 262 cases total. Until the middle of the 20th century, small plague outbreaks were common. The Los Angele Times states that only then did it start to become uncommon. Outbreaks were noted in San Francisco from 1900 to 1908, and epidemics occurred in Oakland in 1919 and LA from 1924 to 1925. The plague was a real issue in 1924 in LA. There were 37 people killed from it.

Comes from fleas

"The bubonic plague, or the Black Plague or Black Death, is caused by a bacteria carried by fleas called Yersinis Pestris. Plague-infected fleas spread it by feeding on small rodents for instance prairie dogs, rats, chipmunks and ground squirrels. Individuals with pets or rodents near can have the fleas on the animal. Then, the flea can jump to the human. The disease is caused when people are bitten by fleas carrying the bacteria. There is a lot of risk in the Southwest. This is where it is the greatest. New Mexico is home to half of all cases, but other cases have occurred in Arizona, California, Nevada and Oregon. Unless the disease becomes pneumonic plague in the lungs, it is non-infections in individuals. It can help to have antibiotics. This has to be within the first 24 hrs of symptoms though.“

Articles cited

Time
Miami New Times
Centers for Disease Control
World Health Organization
Bubonic plague on Wikipedia
Los Angeles Times

Apr
26
2011

Dinosaur art: One of the many dinosaur statues created during the Science Museum of Minnesota's Diggin' Dinosaurs competition in 2007. This one resided near the Lake Harriet bandshell in Minneapolis, MN.
Dinosaur art: One of the many dinosaur statues created during the Science Museum of Minnesota's Diggin' Dinosaurs competition in 2007. This one resided near the Lake Harriet bandshell in Minneapolis, MN.Courtesy Mark Ryan
Over at the Smithsonian's Dinosaur Tracking blog, dinosaur maniac Brian Switek has a cool article about a little girl named Annabelle who had visited New York's Museum of Modern Art (MoMA) recently and was miffed that it didn't contain any dinosaurs ("You call yourself a museum", she spewed on a comment card). Switek covers the usual early and well-known dinosaur artists such as Benjamin Waterhouse Hawkins, Charles Knight, and Rudolph Zallinger and also mentions not only some of today's science illustrators, but also a guy I found really interesting named Allan McCollum who makes some very unusual dinosaur artwork using bone casts and other methods. He creates the dinosaur art for art's sake rather than scientific Occasionally, I've come across other dino art for art's sake, even here in the Twin Cities. Some readers will remember a few years back when the Science Museum of Minnesota held a competition called Diggin' Dinos that involved local artists painting several colorful dinosaur statues in celebration of the museum's 100th anniversary. There was a ton of dinosaur art created then, and some of the statues can still be found around the Twin Cities. Maybe the MoMA would be interested in exhibiting some of those, so next time poor Annabelle visits there she won't be disappointed.

Why the MoMA Should Have Dinosaurs

Apr
22
2011

Meat: Is it your good friend, or old enemy? Tell us.
Meat: Is it your good friend, or old enemy? Tell us.Courtesy Another Pint Please...
Ok, Buzzketeers, buckle up for some meaty issues, juicy discussion, and humorless punnery. But first:

Do you eat meat?

Let me say off the bat that this isn’t a judgment thing. Yeah, I am judging you, but only on your grammar, clothing, height, gait, pets, personal odor, and birthday.

But not on your diet. So there will be no bloodthirsty carnivore or milquetoast vegetarian talk here. Y’all can have that out on your own time.

This is more of what I like to call an entirely unscientific poll about meat, the future, and your deepest secrets. (Depending on what you consider secret.)

When you get to the end, you can see what everyone else voted.

Tell us, do you eat meat? (click here for the poll)

Or jump right to the results.

Or go ahead and discuss this stuff.

Apr
16
2011

For some reason paleontology news this week seems to cover the whole sensory gamut. First off, there’s a new discovery in China of a Mesozoic mammal named Liaoconodon hui that adds more transitional evidence regarding the evolution of the reptilian lower jaw into the middle ear bones found in mammals. The research was done by paleontologists from the American Museum of Natural History and the Chinese Academy of Sciences.

The guys over at Witmer Lab write about being involved in a study of the evolution of olfaction from small theropod dinosaurs to modern birds. The olfactory bulb is the part of the brain that detects odor, and it seems some modern birds inherited a pretty good sense of smell from their dinosaurian ancestors. Here's some video about it from the Witmer Lab site.

In the seeing department Jennifer Viegas over at Discovery News has a slide show presentation (with text) about a new study appearing in Science that suggests some dinosaurs and other prehistoric reptiles were nocturnal. The study is based on the sceleral ring and larger eye sockets found in the fossil remains of some prehistoric animals. Larry Witmer also mentions the subject on his blog (it’s located below the olfaction post).

Touch and taste – the last two senses - are covered in a new study of lice evolution at the University of Illinois-Urbana, and with the discovery of a new, toothy dinosaur in New Mexico.

Kevin Johnson, an ornithologist at the UI-Urbana, proposes that since lice seem to specialize in the way they annoy their host animals, it’s likely that lice that cause today’s birds to nit-pick, scratch and preen, are descended from lice that pestered feathered dinosaurs. You can read about Johnson’s research here.

Ghost Ranch, New Mexico: The red beds here have produced fossils of a new early carnivorous dinosaur.
Ghost Ranch, New Mexico: The red beds here have produced fossils of a new early carnivorous dinosaur.Courtesy Mark Ryan
Lastly, Daemonosaurus chauliodus ("evil spirit reptile with outstanding teeth") is a new carnivorous dinosaur species found recently at Ghost Ranch in New Mexico. The buck-toothed theropod more-than-likely feasted on all the other creatures it shared its environment with 200 million years ago during the Triassic (yes, I know I’m probably stretching the taste sensory categorization here but I needed something). The discovery of Daemonosaurus in a block of Coelophysis remains is important because it alters scientific thought on the early history of carnivorous dinosaurs. The study was led by vertebrate paleontologist Hans-Dieter Sues of the Smithsonian and appears in the journal Proceedings of the Royal Society B. You can also read about it at Dinosaur Tracking.

Mar
18
2011
It's Friday, so it's time for a new Science Friday video. Science Friday
Science FridayCourtesy Science Friday
Today,
"Of the orchid genus catasetum, Charles Darwin wrote: "I never was more interested in any subject in all my life than in this of Orchids." The male flowers in this genus evolved an unusual pollination program. They propel a package of pollen onto the backs of visiting bees. The bees endure the blow (which would be like a 150-pound person getting hit with a few bowling balls) in exchange for orchid aromas that the bees use to attract mates.
Mar
14
2011

Those sassy whales
Those sassy whalesCourtesy Currier & Ives
Word on the street is that sperm whales may have individual names. I hope so, frankly, because I'm sick of calling them ... that.

Sperm whales, it seems, have calls that are unique to the region they live in. So whales in the Caribbean might have a different call than whales living in the South Pacific. But there are parts of sperm whale calls that are, on the surface, the same in whales around the world.

I say, "on the surface" not as some ocean-related pun, but because there's a part of the whale's call—five clicks at the beginning of a call—that seem to be totally unique to individual whales. All whales make the five clicks, but if you analyze the sound in detail, there are actually subtle variations in the sounds that are unique to the whale making them. Because it comes at the beginning of each phrase, or "coda string," and because the variations are perceptible from every direction (some whale calls sound different depending on how the listener is oriented to the caller), some scientists think that the clicks could represent the "names" of individual whales, who are identifying themselves as they call out.

Pretty neat, huh?

PS—"Pretty neat," but not completely neat, because I probably can't distinguish between the whales' clicks. Here, then, is a short list of names for any whales interested in adopting more standard monikers:
-Herman
-Squid Blood
-Crybaby
-Fudgie
-Moby II
-Gentle Jeff
-Spermy
-Winston

There are, like, dozens of other possible names. These are just the first to come to mind.

Feb
25
2011

Archaeopteryx: Thermopolis specimen.
Archaeopteryx: Thermopolis specimen.Courtesy Mark Ryan
This year marks the 150th anniversary of the announced discovery of the first fossils of Archaeopteryx, a remarkable chimera of both bird and reptile traits. The first evidence identified was a single feather discovered at a limestone quarry in Solnhofen, Germany. This was in 1860. The German paleontologist Hermann von Meyer described the fossil in 1861, naming it Archaeopteryx lithographica. That same year, the first skeletal remains came to light, and although headless, the London specimen, as it became known, showed clearly both avian and reptilian characteristics.

The unique and iconic fossil appeared just two years after publication of Charles Darwin’s On the Origin of Species and helped bolster the naturalist’s theory of evolution through natural selection because its appeared to be a transitional fossil between reptile (dinosaur) and bird. Could Darwin have asked for any better evidence?

Since then nine other specimens have been found, including the Berlin specimen around 1877, which is considered one of most complete. For many years some Archaeopteryx specimens languished in collection drawers because they had been initially misidentified as another creature entirely. In 1970, Yale paleontologist John Ostrom was investigating a so-called pteradactyl fossil at a museum in the Netherlands, when he realized it had been misidentified and was actually an Archaeopteryx. The fossil had been found at Solhofen in 1855, five years prior to the feather! The museum curator was so shaken by Ostrom’s announcement, he clumsily wrapped the specimen in a paper bag and presented it to Ostrom so he could take it back to Yale for further study. Ostrom, by the way, re-ignited the “birds are dinosaurs” debate in the 1960s after his discovery of Deinonychus and his comparison of its structural features with those of birds.

The Thermopolis specimen, the latest Archaeopteryx fossil, became known around 2005 and was donated anonymously to the Wyoming Dinosaur Center in Thermopolis, Wyoming. I happened to visit the museum in June of 2007 during the first week the fossil went on public display, and was able to see the spectacular specimen firsthand. The small fossil (about 1.5 feet square) was displayed behind a small, glass opening in the wall. There was no crowd to speak of so I was able to take in and photograph the fossil for a long stretch of time by myself. Looking at it, your eye is immediately drawn to the distinct feather impressions evident on both its wings and tail. The head, arms, and legs are spread out across the slab, and even though it died 150 million years ago, it looks as flat and fresh as road kill on a modern highway.

About the size of a large crow, Archaeopteryx was an odd amalgam of both bird and reptile. It had slightly asymmetrical flight feathers, wings, and a furcula (wishbone) - all traits found in birds. But its pelvis, skull and sharp teeth were reptilian (although some skull features are bird-like), and it ha a long tail like a reptile. Its bones weren’t hollow, like the bones of modern birds are, nor is its sternum (breastbone) very pronounced; it’s flatter and without a large keel where, in birds, muscles flight are attached. And it also possesses gastralia (“belly ribs”), a feature found in reptiles and dinosaurs. The inner toe (the hallux) in the Thermopolis specimen doesn’t appear to be reversed so it couldn't grasp or perch and was probably more earth-bound than arboreal. Interestingly, its second toe was extensible – meaning it could be pulled back and elevated for tearing into flesh, just like the middle toes of such dinosaurs as Troodon and Velociraptor. Truth be told, if its feathers hadn’t been preserved, Archaeopteryx would have been classified a carnivorous bipedal dinosaur. In fact, one of the existing Archaeopteryx fossil was first identified as a Compsognathus until preparation revealed its feathers.

Solnhofen and much of Europe in the Late Jurassic: A cluster of islands off the coast of the North American continent.
Solnhofen and much of Europe in the Late Jurassic: A cluster of islands off the coast of the North American continent.Courtesy Ron Blakey, NAU Geology
So what kind of environment did Archaeopteryx live in, and why are its fossils so well preserved? Well, during the Late Jurassic, southern Germany and much of the rest of Europe were pretty much a group of large islands poking out of the Tethys Sea off the coast of North America. What is today the Solnhofen quarry was then part of an island lagoon protected by a barrier reef. Geological evidence in the strata suggests the lagoon dried up several times followed by periods of re-flooding with seawater. Mixed into a brackish soup of coral debris and mud, and in a warm climate conducive to rapid evaporation, the lagoon’s bottom water levels became anoxic, that is depleted of oxygen. Low oxygen meant less bacterial activity and subsequently slow decomposition of any organism that happened to die or get swept into the stagnant lagoon. Burial in the carbonate muck was swift, leaving fresh carcasses no time to be pulled apart by currents or scavengers.

Solnhofen limestone has been used for centuries as a building stone. Because the rock’s matrix is so fine and splits so evenly (sediment deposition likely occurred in very calm waters), the material was later quarried to produce stones for lithography, a printing technique first developed in 1796, and the source of Archaeoperyx’s species designation. Many early scientific illustrations, including some of the first images ofArchaeopteryx were preserved as lithographs created using Solnhofen limestone.

Archaeopteryx commorative coin: Germany will issue the 10 Euro coin in the summer of 2011
Archaeopteryx commorative coin: Germany will issue the 10 Euro coin in the summer of 2011Courtesy Federal Republic of Germany
Solnhofen’s fossil record shows that the lagoon’s biological population was diverse. Fish, turtles, lizards and insects, crocodiles, crustaceans, ammonites, squid and starfish, mollusks, pterosaurs, and even the soft remains of jellyfish are preserved in the fine-grained limestone. But the premiere creature is of course the Archaeopteryx, which remains the earliest bird (or most bird-like dinosaur, if you will) known to date. As research on existing specimens continues and new fossils appear it's exciting to imagine what advances will take place in the dinosaur-bird connection debate. Whatever happens, Archaeopteryx lithographica will remain one of the most significant and iconic fossils ever discovered. It's no wonder that later this year on August 11th, the Federal Republic of Germany will issue a 10 Euro silver coin to commemorate the 150th anniversary of the discovery of its most famous fossil.

SOURCES and LINKS

Witmer Lab Archaeopteryx blog
UCMP Archaeopteryx page
Solnhofen limestone of the Jurassic

Feb
09
2011

Polyommatus blue butterfly
Polyommatus blue butterflyCourtesy Rongem Boyo
One of my favorite 20th century writers is the Russian-born Vladimir Nabokov (1899-1977). Many people were (and many probably still are) shocked by the subject of his best-known novel, Lolita, which he wrote in English in the early 1950s. But Nabokov’s use of the language in that book - and others - is at times so exquisite and so finely-crafted, that it’s equally shocking to realize that English wasn’t his native tongue but rather his second language taught to him by his governess while he was growing up in St. Petersburg. He was also well versed in French, so language played an important role in his life, as his many novels, poems, and essays attest. But growing up to become one of the 20th century’s greatest writers was not something he planned, because at age seven he had discovered another passion: collecting butterflies.

Nabokov said in later interviews that had it not been for the 1917 Russian Revolution, he would have probably been a lepidopterist at some obscure museum in St. Petersburg. But fate brought him eventually to the United States where (before publication of Lolita made him independently wealthy) he made his living mainly by teaching literature at Wellesley College and Cornell University. He also volunteered at the American Museum of Natural History - where he learned to dissect butterflies - and at the Harvard Museum of Comparative Zoology.

During the summer months he liked to mix his passions as he explained in the afterword to later editions of Lolita:

Every summer my wife and I go butterfly hunting. The specimens are deposited at scientific institution, such as the Museum of Comparative Zoology at Harvard or the Cornell University collections. The locality labels pinned under these butterflies will be a boon to some twenty-first-century scholar with a taste for recondite biography. It was at such of our headquarters as Telluride, Colorado; Afton, Wyoming,; Portal, Arizona, and Ashland, Oregon that Lolita was energetically resumed or on cloudy days.

Around 1945 he came up with a new theory of migration for the Polyommatus blue butterflies. Without the use of genetics and by studying anatomical features (mostly genitalia), Nabokov speculated that Polyommatus blues found in South America evolved by migrating in five waves from Asia across the Bering Strait. At the time the prevailing migration theories involved land bridges across the Pacific, so no one gave Nabokov’s hypothesis much weight.

Professional lepidopterists weren’t that impressed with Nabokov. They admitted he was decent enough researcher and at describing specimens (his published descriptions numbered in the hundreds) but they didn’t think he offered much in the way new ideas.

But now it seems Nabokov has been vindicated. A new report in the journal Proceedings of the Royal Society of London has determined - through DNA analysis – that Polyommatus blues have indeed evolved through five separate migrations from Asia over the Bering Strait.

“It’s really quite a marvel,” said co-author Naomi Pierce of Harvard. Pierce was part of a team of lepidopterists from England and the United States that made several expeditions to Chile to study and collect specimens of Polyommatus blues, then returned to the lab for gene sequencing and computer analysis of the data. The results showed that the Polyommatus blues did indeed originate in Asia, and were more closely related to that 10 million year-old ancestor than they were to their South American neighbors. But they also revealed that the first wave arrived when the temperature along the Bering Strait was warmer. But that temperature was in decline, and subsequent migrations brought in hardier species of Polyommatus, better suited to colder temperatures that correlated with the temperature range existing around the Bering Strait at the time of each wave. The conclusions matched Nabokov’s hypothesis to a “t”.

“By God, he got every one right,” Dr. Pierce said. “I couldn’t get over it — I was blown away.”

Paleontologist Stephen J. Gould included an essay in one of his many books about Nabokov’s split loyalties between art and science (he termed it “intellectual promiscuity”) proposing if the writer had kept focused on just writing he might have created another Lolita. On the other hand, Gould mused, if Nabokov had only studied butterflies, he could have become a well-known (at least in some obscure circles) lepidopterist. If it sounds like the old adage “you can’t serve two masters”, Nabokov seems to have pulled it off equally well in both arenas. I think had it not been for his writing and the lifestyle it afforded him, he wouldn’t have had the luxury of pursuing lepidoptery as fervently and successfully as he did; and without his butterfly collecting, he never would have written his masterpiece. If you asked the seven year-old Vladimir what he wanted most to be remembered for, his answer wouldn’t have been “writing a great novel”. He had another aspiration in mind, which he fulfilled several years later during one of his summer breaks from teaching. While visiting the Grand Canyon with his wife, Nabokov discovered a new species of butterfly which he named Neonympha dorothea in honor of a family friend who was traveling with them. His satisfaction poured out a couple years later in a poem:

I found it and I named it, being versed
in taxonomic Latin; thus became
godfather to an insect and its first
describer – and I want no other fame.

- On Discovering a Butterfly (1943) by Vladimir Nabokov.

SOURCES
NYT story
Bioephemera article

Feb
04
2011

Dragonfly wing: Its structure is aiding wind-power researchers
Dragonfly wing: Its structure is aiding wind-power researchersCourtesy Mark Ryan
Researchers in Japan are studying the wing structure of dragonflies to help improve how micro wind turbines perform during high winds. Micro turbines are small, affordable energy converters that can be used in both urban and rural settings where giant turbines would be too expensive, too large, and too impractical. Micro turbines can be set up relatively easily in configurations of a single unit or as a bank of several units, and the energy generated can be stored in batteries.

They work on the same principle as the large turbines, but can generate power in wind speeds as low as 4 or 5 miles per hour. One fallback, though, is their generators can get overloaded when hit with high storm winds, producing more energy than the system can handle. Large turbines solve this problem by tilting their propellers - either by computer or otherwise - and adjusting their rotation speed. But that kind of technology just isn’t affordable with micro turbines.

That’s where studying dragonfly wings comes in. Aerospace engineer Akira Obata of Nippon Bunri University in Oita, Japan wondered how dragonflies were able to remain stable in flight at low speeds. He placed a plastic model of a dragonfly wing into a large tank of water laced with aluminum powder and videotaped the flow patterns. He noticed that as the water flow slowed down vortices arose on the wing’s surface that allowed the water to pass over the wing at the same speed, thus keeping it stable. But when water flow sped up the wings aerodynamics performance decreased.

So, Obata developed an inexpensive paper micro turbine with similar “dragonfly wing” bumps on its surface and it did just as he hoped. When air speeds flowing over the turbine wing increased between 15 and 90 mph, rather than speeding up its rotation and overwhelming its battery, the micro turbine curved into a conical shape that stunted rotation and kept power generation low.

New Scientist story
CNBC story on homemade micro turbine
Make your own micro turbine