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Posts tagged "spiders"

scienceyoucanlove:

Today in cute science: 

Meet the green jumping spider (Mopsus mormon), Australia’s largest—and perhaps cutest—jumping arachnid. These spiders hunt in the day time, moving fast to attack their prey, and camouflaging against green leaves. If you see one, leave it alone. Although their bite won’t kill you, it’s extremely painful.

Read more: http://bit.ly/HrvdHE via Project Noah

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(via afro-dominicano)

mucholderthen:

Igor Siwanowicz is no stranger to Tumblr; but there’s a great gallery of his confocal micrographs posted at WIRED 8 October 2013  ||
Acknowledgment is made to KQEDScience for an earlier and briefer post about this article.
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Under the Microscope,
Some Things Look Too Crazy to Be Real
by Brandon Keim -  WIRED

Physicists wonder if there are other universes, but biologists have already found them. Just look through a microscope and there you are, in a different world of life.

Igor Siwanowicz, a neurobiologist at the Howard Hughes Medical Institute’s Janelia Farm Research Campus, visits often. Acclaimed for his macroscopic photography of insects (like the jumping spider above) and other small animals, he uses microscopes to explore ever-smaller realms.

"I first laid hands on my microscope only three years ago, when I changed fields," said Siwanowicz. "I used to work as a biochemist, but I decided that neurobiology was more in tune with my naturalist approach. Plus they have these cool toys: confocal laser-scanning microscopes.”

Siwanowicz took Wired on a tour of some of his best work.

Continue with Some Things Look Too Crazy to Be Real

IMAGES
Jumping Spider
Slug moth caterpillar
Jumping spider eyes

Fascinated by microscopes and imaging technologies, Siwanowicz has deep appreciation for the eyes of jumping spiders, which he describes as “a fantastic engineering solution.”

Their many eyes — each individual has four pairs — are extremely powerful. Like telephotos on cameras, they’re capable of great magnification. Their field of view, however, is very narrow, and the lenses are part of the spiders’ exoskeletons. They can’t be moved unless the spider moves its entire body.

To compensate, the spiders’ retinas are mobile, adjusting position in relation to their lenses and scanning the incoming projection from different angles. “Under magnification, you can see when they’re looking at you,” said Siwanowicz. “They’re not moving, but their eyes are turning black. The retinas are absorbing all the light. They’re looking right at you.”

scienceyoucanlove:

How Do Spiders Fly for Miles? Mystery Solved


As if spiders aren’t unnerving enough, did you know that some of them use an electrostatic charge to leap into the air and fly for miles? They’re probably coming to your house.


The flight of the gossamer spider was a curiosity even to Charles Darwin, who noted that his boat, the HMS Beagle, was “inundated by ballooning spiders on a relatively calm, clear day,” according to a new paper by Peter Gorham of the University of Hawaii that’s posted on the arXiv website. (Also see “Darwin the Buddhist? Empathy Writings Reveal Parallels.”)

Darwin watched two species of spider, one smaller, one larger. The first raised its abdomen, released a thread and launched itself horizontally with “unaccountable” speed. A larger species released several threads more than a yard long, which he described as undulating “like films of silk blown by the wind.” The spider then let go of the post it had been perched on, and flew away —an arachnid paraglider in action.

Darwin thought thermal air currents could be the secret of the spiders’ aerial abilities, but that doesn’t explain things like why the threads fanned out and how even fairly heavy spiders launched so quickly when the air was relatively still. Also, as the Physics arXiv blog notes, these spiders have been found at altitudes as high as 2.5 miles (4 kilometers) and are not likely to have gotten there by hot air alone.

Darwin and others also theorized that “electrostatic repulsion” played a role in the fanning of the threads. Lo these many years later, Gorham says that indeed, electrostatic forces could determine the spiders’ flight. (Watch a video of the world’s largest spider.)

Electrifying Research

“There are thus a wide and plausible range of processes by which the strands can acquire initial charge,” Gorham writes. One of these is the charging of the strands by the earth’s atmosphere during spinning in a process called “flow electrification.”

From the arXiv blog:

“There must be a source for this charge, of course. Gorham thinks a likely origin is the Earth itself, which has a negative charge density of about 6 nanoCoulombs per square metre on average. That’s more than enough to give the silk a healthy boost and spiders may well be able to pick out prominences where the charge density is much higher.”

All this explains the spider’s launch power in still air, why large spiders can get such a lift and why the silk strands fan out: “because their negative charges repel.” (Also see “Tarantulas Shoot Silk From Feet, Spider-Man Style.”)

The arXiv blog notes that Gorham’s theory still needs to be tested by some “enterprising biologist.” For that individual and for Gorham, how remarkable it must be to work with ideas blown in on gossamer silk all the way from Darwin.

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afracturedreality:

Jumping Spider’s Eyes

The head of a jumping spider is prepared with fluorescent markers and imaged using a confocal laser scanning microscope. Both images actually depict the same side and depth level of the specimen’s head; the photomicrograph on the left has been flipped horizontally for a side-by-side comparison of fluorescence.

To fit a particular experiment, specific fluorescent dyes are often selected after careful consideration. In both of these images, cell nuclei are visualized with TO-PRO®-3, a monomeric cyanine stain with far-red fluorescence. On the left, autofluorescence is visualized in blue; on the right, microfilaments (cyan) are visualized with rhodamine phalloidin.

Images are by Igor Siwanowicz, Max Planck Institute of Neurobiology, Munich, Germany.

thescienceofreality:

This is Your Web on Drugs

“In 1995 a group of NASA scientists experimented with drugs, literally. They studied the effects that various legal and illegal drugs have on house spiders, and specifically on the way they weave their webs. The results are both surprising and… not.

The NASA scientists suggested the possibility of analyzing the periodic structure of the spiderwebs (or lack thereof) as a means of determining the relative toxicity levels of drugs. They do not seem to have continued down that road, however; one obstacle may have been the difficulty of extrapolating a given drug’s toxicity to humans from its toxicity to spiders. Though similarities between effects on the two species do seem to exist, I’m not sure caffeine makes me feel quite like THAT. In fact, if I wove spiderwebs, that one would probably be pre-morning-cup-of-coffee.

Such questions as what the research had to do with space shuttles or Mars rovers, where the scientists got the drugs, and what happened to the spiders later unfortunately cannot be answered here. The relevant NASA briefs are cited by other academic papers and New Scientist Magazine, but aren’t themselves published on the web. The world wide one, that is.”


Read more here and here, and see what happens to their mental state here.

Jeepers, Peepers: Why Spiders Have So Many Eyes

Is it their eight creepy-crawly legs or their eight beady eyes that make spiders a spooky Halloween staple? Either way, new research suggests all those extra pairs of spider peepers have their own roles to play in keeping the arachnids safe.

Jumping spiders, a group of spiders that actively hunts its prey rather than trapping it in webs, have four pairs of eyes (as do most spiders). A new study finds that while the center, or principal, pair of eyes is good at picking out details, one of the side pairs is crucial for warning spiders when something is coming their way.

This “looming response” is the equivalent of a human ducking and covering when a baseball flies toward his or her face. But humans rely on just one pair of eyes to both avoid the baseball and see the details of its stitching. Jumping spiders use four eyes for the same tasks.

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amnhnyc:

The Museum is home to the largest collection of spiders in the world, one that is still growing through the fieldwork of scientists such as Norm Platnick, Curator Emeritus in the Division of Invertebrate Zoology. Platnick, who has discovered and described more than 1,600 new spider species, says there are many more to find. Find out more about his research after the link: http://bit.ly/QntTCC

This side view of the claws found at the tip of an Andean goblin spider’s first pair of legs was taken using a scanning electron microscope. 

© AMNH/N. Dupérré

fiendfyre-x:

Spotted this girl in my back yard. I’ve never seen one carrying an egg sac before and thought it was pretty neat.

Wolf spiders are unique in the way that they carry their eggs. The egg sac, a round silken globe, is attached to the spinnerets at the end of the abdomen, allowing the spider to carry her unborn young with her. The abdomen must be held in a raised position to keep the egg case from dragging on the ground, however despite this handicap they are still capable of hunting. Another aspect unique to wolf spiders is their method of infant care. Immediately after the spiderlings emerge from their protective silken case, they clamber up their mother’s legs and crowd onto her abdomen. (via)

(via serpensorrtia)

Spider silk spun into violin strings

A Japanese researcher has used thousands of strands of spider silk to spin a set of violin strings.

The strings are said to have a “soft and profound timbre” relative to traditional gut or steel strings.

That may arise from the way the strings are twisted, resulting in a “packing structure” that leaves practically no space between any of the strands.

The strings will be described in a forthcoming edition of the journal Physical Review Letters.

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cwnl:

Spiders Hunt With 3-D Vision

With their keen vision and deadly-accurate pounce, jumping spiders are the cats of the invertebrate world. For decades, scientists have puzzled over how the spiders’ miniature nervous systems manage such sophisticated perception and hunting behavior. A new study of Adanson’s jumping spider (Hasarius adansoni) fills in one key ingredient: an unusual form of depth perception.

Like all jumping spiders, the Adanson’s spider has eight eyes. The two big ones, front and center on the spider’s “face,” have the sharpest vision. They include a lens that projects an image onto the retina—the light-sensitive tissue at the back of the eye. That much is common in animal vision, but the jumping spider’s retina takes things a step further: It consists of not one but four distinct layers of light-sensitive cells. Biologists weren’t sure what all those layers were for, and research in the 1980s made them even more enigmatic. Studies showed that whenever an object is focused on the base layer, it is out of focus on the next layer up—which would seem to make the spider’s vision blurrier rather than sharper.

That led to a “long-standing mystery,” says Duane Harland, a biologist who studies spider vision at AgResearch in Lincoln, New Zealand, and who was not involved in the new study. “What’s the point of having a retina that’s out of focus?” The answer, it turns out, is that having two versions of the same scene—one crisp and one fuzzy—helps spiders gauge the distance to objects like fruit flies and other prey.

Continue..

(via afro-dominicano)

cwnl:

Spiders’ Hundreds of Fine Hairs Are Hundreds of Ears

Side Note: I have a thing for fuzzy insects, more specifically the tiny jumping spiders that I’ve always found to be the most adorable creatures on the face of the planet [next to my cat]. This is a very interesting article that caught my eye via Wired that explains how these little guys not only see with their multiple eyes.. but also with their hair!

How their tiny specialized hairs do it has puzzled researchers for decades, but one team of scientists may have found a break. Their physics-focused work suggests each hair acts like a single, independent ear — not a network of ear parts that, together, turn a spider’s exoskeleton into one giant ear, as was previously assumed.

“Nobody had looked at these hairs in just the right way. When you look at what they are mechanically optimized to do, you could design better ones,” said physicist Brice Bathellier of the Institute Of Molecular Pathology in Vienna, who co-authored a study of trichobothria hairs Dec. 14 in the Journal of the Royal Society Interface.

“But nature optimizes. Animals evolve under stringent conditions,” Bathellier said. “So it became a question of what [the hairs] actually do, what type of signals tell animals ‘I should leave’ or ‘that’s just wind blowing on me.’”

Trichobothria are fine hairs found on spiders, insects and other animals with exoskeletons. The hairs are so sensitive that some can pick up air movement down to one ten-billionth of a meter, roughly the width of an atom, allowing animals to feel the presence of nearby predators and prey. (Crickets and flies, for example, have tufts of them on their rumps to sense prowling enemies.)

Journal: Air motion sensing hairs of arthropods detect high frequencies at near-maximal mechanical efficiency

Follow the link for more information and a nice video provided within the article.

(via afro-dominicano)

Tarantula MRI Reveals Strange Double Heartbeat

Spider hearts may contract in a unique double beat. By placing tarantulas in a magnetic resonance imaging scanner, biologists from Edinburgh University made a video of a living spider’s beating heart.

“In the videos you can see the blood flowing through the heart and tantalizingly it looks as though there might be ‘double beating’ occurring; a distinct type of contraction which has never been considered before,” said Gavin Merrifield in a press release. Merrifield presented the research at the Society for Experimental Biology Annual Conference in Glasgow last month.

Merrifield and his colleagues used special MRI scanners, built for medical research on rats and mice, at the Glasgow Experimental MRI center, to measure heart rate and cardiac output in tarantulas. Most MRI technology is used purely for medicine, but it could branch out into new areas of biology.

“On the more academic side of things if we can link MRI brain scans with a spider’s behavior, and combine this with similar data from vertebrates, we may clarify how intelligence evolved,” Merrifield said.

Article Source: Wired

(via afro-dominicano)