Blogs / Discoblog

If you thought going to the club was bad, imagine having to dance in front of potential mates for over an hour and a half, lest they will eat you. Male Australian redback spiders, members of the black widow family, pay the ultimate price if their mating dance doesn’t impress.

Here’s how it works, via Livescience.com:

Males, which are just 1 percent to 2 percent of a female’s body weight, dance about the web of a potential mate, plucking at the threads and sending out vibrations. Once the male redback has performed an adequate dance, the female will allow him to mount her and insert one of his two palps, or copulatory organs, into one of a pair of sperm storage organs. The male then somersaults to place its abdomen directly above his mate’s fangs. That’s perfect positioning for the female to begin devouring the male’s body.

To avoid being gobbled up by the female halfway through mating, males need to dance for 100 minutes, according to new research. But the dancing males better have a good internal clock. Females can’t determine the source of courtship, so if the dancer exceeds the optimal time, a slick male could sneak in a mate with the female while the dancer ends up alone on the web.

For a video of the life-or-death dance, click on over to the Discovery News.

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Image:  Ken Jones

To see if a whale’s libido is going full-throttle, grab a pair of nylons and head to the ocean, reports the New Scientist:

For the first time, testosterone and progesterone—two key hormones that signal whether whales are pregnant, lactating or in the mood to mate—have been extracted from whales’ lung mucus, captured in nylon stockings dangled from a pole over their blowholes as they surface to breathe.

This method could allow scientists to study whales without having to slaughter them, and could be used to simply give them a pregnancy test to try to learn why some species aren’t breeding, say the authors of the study.

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Image: flickr / percita

It’s a question you wouldn’t be surprised to hear a toddler ask: Do butterflies have ears? Well yes, yes they do. And one species was recently discovered to have ears on their wings. The blue morpho butterfly from Central and South America has beautiful bright blue wings complete with a simple ear structure that picks up noise and relays it to the brain.

Via MSNBC.com

In the new study, Kathleen Lucas of the University of Bristol in England and her colleagues were interested in the odd-looking hearing membrane that sits at the base of the blue morpho’s wing. The tympanal membrane, as it is called, is oval-shaped with a dome at its center that kind of resembles the yolk at the center of a fried egg, Lucas said.

Researchers determined that the butterflies can distinguish high and low frequencies, uncommon in simple ears, and they speculate this could help them determine if a hungry bird is about to swoop down and attack.

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Image: flickr / DavidDennisPhotos.com

Soccer moms and Little League dads aren’t the only ones living the good life in the ‘burbs. Eastern long-necked turtles in the Australian suburbs are living fat and happy, according to new research in the journal Biological Conservation.

The finding came as a surprise to the research team. According to BBC News:

“We expected suburban turtles to move around less than those on the nature reserves in response to the many threats that suburban turtles could encounter, but we found the opposite,” says Dr John Roe, a member of the research team from the Institute for Applied Ecology at the University of Canberra, Australia. “Suburban turtles traveled longer distances and occupied home ranges nearly three times larger than turtles in the nature reserves.”

Seems like suburbanites are forcing McMansions and longer commutes on turtles now too.

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Image: flickr / reggie35

Humans aren’t the only ones who enjoy a game of soccer (or football, depending on where you’re from). A new video has surfaced showing dolphins “kicking” around a ball—only the ball, in this case, is a jellyfish.

From the Daily Mail:

A team of marine biologists were astonished to see a dolphin swim under a jellyfish and with a quick flick of its tail shoot it out of the water. The bottlenose dolphins were caught on video performing the strange activity off the Welsh coastline. One dolphin was able to flip the jellyfish six feet up in the air.

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Video: YouTube / countrysidecouncil

Basilisk lizards have garnered the nickname Jesus Lizards over the years for their ability to “run” across the surface of water. However, these fast little guys don’t rely on miracles, say scientists. New footage of the lizard, filmed at 2,000 frames per second, will air on the BBC on Monday October 19, revealing the science behind the lizards’ water run. From the Huffington Post:

Simon Blakeney, a producer who had filmed the lizard for the BBC told Matt Walker from BBC Earth News, “Because [the lizards] run so fast they create a bubble as their feet hit the water and then they push off from this bubble before it bursts,” says Blakeney. By balancing and pushing off from these bubbles, the lizard is able to “walk” on water.

The 2-4cm lizards only know one speed—full throttle—and this forces their bodies upright as they sprint across the water. In an older video, courtesy of National Geographic, there is considerable splashing as one lizard’s feet appear to sink below the surface during a run. However scientists say this is due to water being yanked up as the lizards pick their feet up off the surface of the water.

We’ll have to wait for the new footage, which is slowed down to 1/80th the speed of real life, to see for ourselves. But for now, check out the NatGeo video, showing a basilisk lizard scooting across the water in around 49 seconds.

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Video: YouTube / National Geographic

Finally, a way to combine our love of taxidermy with our love of technology.

From Kottke.org:

Fearing that the natural world is being replaced by technology, the artist [Kasey McMahon] installed a working computer inside of an idle beaver. First, she crafted a computer from the motherboard up, tested it, then hollowed out a stuffed beaver and molded the two together using spandex spray, resin, and fiberglass. After three months of work, the result was Compubeaver…

Yes, it’s an actual working computer inside a stuffed beaver. And you too can build one in 29 easy steps!

Also, don’t miss Compubeaver’s sidekick, Text-O-Possum, which comes equipped with a laser in it’s back leg that projects an image of a keyboard. So it doesn’t actually text, you say? Well that doesn’t matter, since carrying this thing around will ensure that no one wants to talk to you.

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Image: Psycho Girlfriend

“Really! I was born that way! I swear!” A new species of shark was discovered in California recently, called the Eastern Pacific black ghostshark. It’s part of a group known as big black chimeras, and members of the species have actually been laying around pickled in museums since the 1960s—but only recently have scientists realized that the black ghostsharks were in fact a separate species.

One possibility is that past scientists were too distracted by the sharks’, er, highly unusual feature that they lumped them in with the other chimeras.

Douglass Long, author of the study (PDF) detailing the new species, described the shark to National Geographic News:

Male chimeras…have retractable sexual appendages sprouting from their foreheads. These organs, which resemble a spiked club at the end of a stalk, may be used to stimulate a female or to pull her closer—though these are still assumptions, Long said.

So basically these guys have a mace swinging from their forehead that they use to club female sharks. Talk about a remarkable trick of animal mating.

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Image: MBARI

Scientists have a neat little tool they use to read your mind. It’s called fMRI (functional Magnetic Resonance Imaging for those not in the know) and it seems to be everywhere these days. Scientists are using it for everything from looking at your dreams to studying the brains of jazz musicians to IDing the part of the brain that is activated when we get grossed out.

But not everyone believes fMRI studies are all that useful. In fact, one group recently set out to show how the studies, if not done carefully, can be downright misleading. And to do this, they used dead fish.

Scientists  scanned the brains of deceased Atlantic salmon with fMRI to teach their colleagues a lesson in data analysis. The Great Beyond, a Nature blog, has the details:

The salmon was presented with a series of photographs, and then asked to determine what emotion the individual in each picture was experiencing. The team then analyzed tiny areas in the brain (voxels – like pixels but for volume) using basic methods for controlling for error. Surprisingly, report the team, “several active voxels were discovered in a cluster located within the salmon’s brain cavity.”

Of course the salmon were dead, so there shouln’t have been any activity detected. The point was to highlight the false-positive rate inherent in fMRI studies. More from TGB:

They are making a serious point about the dangers of not taking account of false positives. When you image the brain using fMRI, you’re basically asking whether there is activation in each of thousands of voxels. Because there are so many voxels (130,000 in a typical fMRI scan), “the probability of a false positive is almost certain,” writes Bennett [the study's lead author] in the introduction.

The research team says some studies do not do enough to rule out the false positives. Their results were presented at the 2009 Human Brain Mapping Conference in San Francisco.

More on what should be done to correct the problem at Neuroskeptic and Neurolaw.

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Image: flickr / denn

A leading British conservationist is reportedly playing the “eco-xenophobia” card. While the Brits ramp up their campaign to weed out so-called “alien species” (aka “not native to Britain”) like gray squirrels, parakeets, and rhododendrons, Ian Rotherham, Director of the Environmental Change Research Unit at Sheffield Hallam University, is saying not so fast. He believes that these foreign species attract extra attention simply because they ain’t from ’round here, and that they are no more harmful than any other creatures on British soil.

The London Guardian quotes Rotherham on his reasoning:

“I’ve coined the term ‘Eco-xenophobia’ to stress the idea that we are making judgements not through objectively supported science but through mistaken ideas of what is native, what is alien, and hence what is good or bad,” he said. “Many of these ideas and concepts are very recent and disguise real and serious issues of problem species and of sustainable land management and custodianship. What’s worse perhaps, is that they resonate with ideas growing with the [British National Party] in the UK, and with other right wing groups across Europe.”

The Department for the Environment, however says that invasive species cost the British economy at least £2billion a year, so yeah, they are kind of a problem.

The New York Times reported back in January on one way the Brits are culling their vermin—squirrel soup and pie, anyone?

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Image: flickr / infomatique