Every year, Nikon asks photographers and scientists to enter their most magnificent microscopic photos into the Small World photomicography competition, and every year, they dazzle. Here are three of the coolest photos from among this year’s winners.
Jennifer Peters and Michael Taylor, St. Jude Children’s Research Hospital/Nikon Small World
First Place: This winning photo depicts the blood-brain barrier, the seal between capillaries and the brain, of a live zebrafish embryo. To produce the image, researchers genetically engineered components of the barrier to fluoresce under a confocal microscope, took a series of photos at 20x magnification, then combined the images to create this one. This is believed to be the first time the developing blood-brain barrier of a live animal has been captured on film.
Dr. Peter Jäger, an arachnologist from the Senckenberg Research Institute in Frankfurt, was just taking a break from a TV shoot in a cave in Laos—like you do—when he came across this gigantic harvestman, or daddy longlegs. A pair of its legs spans 33 cm, over a foot, from end to end, making it one of the largest-known members of its order, the opiliones.
Don’t take this the wrong way, arachnophobes, but it missed the record for longest-legged daddy longlegs by a centimeter. That distinction went to a harvestman from South America, whose legs spanned 34 cm.
Harvestman photo via Senckenberg Research Institute
This lucky wasp did not get eaten by the spider attacking it. But when we say “lucky,” we mean it only in a certain sense: moments after the wasp’s capture, they were both overtaken by a flow of tree resin and were preserved in amber for the next 100 million years, while their species and their dinosaur contemporaries from the Early Cretaceous period went extinct. The amber fossil is described in a new paper by George Poinar, the entomologist whose investigations into extracting dinosaur DNA from amber-locked mosquitoes inspired the book and movie, Jurassic Park. New research into the half-life of DNA puts that out of the question, but who knows: it might not be too late for these ancient bugs to cut a movie deal.
Photo via Oregon State University/Flickr
What’s the News: The surprising strength of spider silk has fascinated scientists (and everyone else) for years: it’s stronger than steel, yet incredibly flexible. A new paper gives some delicious details that explain how, exactly, spider silk has such superpowers.
Go With the Flow, Then Stay Strong: The strand of silk that a spider hangs from can stretch to double its usual length. But then, after that virtuosic show of elasticity, it turns rigid.
The reason for that, this team found previously, is that on the molecular level, spider silk is made of scrunched-up proteins that are pulled straight as the silk stretches. But once they’ve been fully unfurled, the proteins lock into a new, stiff pattern called a beta-sheet nanocrystal. For a spider, having the molecules snap to stiffness after stretching is probably analogous to a rock climber arresting a rappel by clipping the end of her rope in place.
Spiders are covered with fine hairs that can detect the faint movements of an enemy creeping closer, or a prey insect moving nearby. Scientists had long thought that these hairs functioned like the hairs humans have in our ears, which each tremble in response to a specific frequency and have to work together for us to hear sounds. But a new experiment suggests that each individual hair on a spider is capable of responding to a whole spectrum of sound, thus acting as an ear all on its own. As Dave Mosher writes at Wired:
The hairs responded best to sounds between about 40 Hz, a low rumble of bass, and 600 Hz, a car horn (humans ears can detect between 20 Hz and 20,000 Hz). That they picked up such a wide range of frequencies at all could overturn previous assumptions about how trichobothria [as the hairs are called] work.
“They operate like band-pass filters or microphones, not like the hairs in a human ear,” Bathellier said. In effect, each hair is its own ear that filters out background noise and zeroes in on biologically relevant information, such as an unwary cricket’s hopping or a spider’s sneaking.
How all these tiny “ears” work together, though, is still a mystery—further studies will have to investigate how the hairs’ vibrations affect spiders’ nervous systems.
What’s the News: Among the many creepy denizens of Australia—such as the red back spider, seen here hauling a lizard into its nest, and the saltwater crocodile, which kills with its distinctive “death roll”—the assassin bug is right at home. With its erratic, long-legged walk, it stalks along spiders’ webs, caressing its prey with its antennae and then stabbing them with its beak. Now, scientists who spy on these spider-eaters report that the bugs have yet another charming behavior in their toolkit: using the breeze as cover when they go in for the kill.
Nephila jurassica, with a 5mm scale bar
What’s the News: Researchers have unearthed the largest fossilized spider yet, announced in a study online today in Biology Letters. The fossil, a Jurassic Period ancestor of the modern orb-weaver spider, gives scientists a glimpse not only into the evolutionary history of orb-weaver spiders, but how these ancient arachnids might have impacted the evolution of insect species that could be snared in the webs.
Step 1: Put study subject in MRI machine. Step 2: Show subject video of a huge, hairy tarantula creeping toward their toes. Step 3: Watch panic light up in the brain.
For a study out in this week’s Proceedings of the National Academy of Sciences, Dean Mobbs and colleagues put their subjects through this fright fest to sort out how the brain responds to different parts of a threat. It’s not all about the presence of a creepy crawler, Mobbs found—it’s whether that creepy crawler is creeping closer.
As the spider advanced, MRI scans allowed researchers to see flashes of activity switch from the volunteer’s prefrontal cortex – a region associated with anxiety – to a spot in the midbrain known to involve intense fear. But the neural terror waned when the tarantula retreated, “regardless of the spider’s absolute proximity,” wrote the study’s authors. In other words, as long as the spider was moving away, no matter how close it still was, the volunteers relaxed. [MSNBC]
For most insects, walking onto a spider’s web and disturbing the sticky threads would be a very bad idea. The distinctive vibrations of wriggling prey only serve to draw the spider closer and inevitably ends in the insect getting bitten, wrapped in silk and digested. But this story doesn’t always unfold in the spider’s favour. Some vibrations aren’t made by helpless prey, but by an assassin lurking on the web.
The assassin bug (Stenolemus bituberus) is a spider-hunter. Sometimes, it simply sneaks up to spiders on their own webs before striking, plunging its dagger-like mouthparts into its prey. But it also has a subtler technique. Sitting on the web, it plucks the silken threads with its legs, mimicking the frequency of weakly struggling prey. These deceptive vibes are an irresistible draw to the spider, who rush towards their own demise.
For more devious details, read the rest of this post at Not Exactly Rocket Science.
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Video: Anne Wignall / Macquarie University
You’ve probably heard about the extraordinary strength of many kinds of spider silk, but researchers in China say they’ve figured out another fascinating property of the silk—how it catches water in the air—and created their own copycat material.
For a study in Nature, Chinese scientists looked at the small, non-poisonous cribellate spider’s silk. The secret, revealed by scanning electron microscope, lies in the silk’s tail-shaped protein fibres which change structure in response to water. Once in contact with humidity, tiny sections of the thread scrunge up into knots, whose randomly arranged nano-fibres provide a roughly, knobbly texture [AFP]. In between these knots are smooth areas where the fibers are neatly aligned, allowing water to slide along until it hits a knot, where dewdrops accumulate.