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Web recognition system can identify spider species automatically

An orb weaver spider web.
Dario Trimarchi
There could be a way to speedily identify the different species of spider that are found in dense jungle and forest, using an automatic web recognition system.

Usually, working out which spiders are which can be a cumbersone, long-winded process, involving tweezers and specimen jars and many hours under a bright lamp in the case of rare and unusual species. A team from the signals and communications department of the University of Las Palmas de Gran Canaria, led by Jaime Ticay-Rivas, decided to instead use a spider's web as a kind of "biometric identification" to automate the process.

Using photographs of spider webs taken in Costa Rica and Panama, the team applied various image clarification techniques to isolate the shape of the web. Those techniques include principal component analysis, independent component analysis, discrete cosine transform and wavelet transform—basically, techniques that identify the key, most distinctive part of the centre of a web by isolating it from the background "noise" in the image. Then, it correlates that with characteristics found in the rest of the web to further narrow the range of possibly species.

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Wasp spider foreign exchange program shows shifting heat tolerance

The march of wasp spiders into more northerly territories demonstrates how climate change may prompt species to alter their temperature preferences.

By analyzing the genetic diversity and distribution of the wasp spider (Argiope bruennichi) geneticists at the Max Planck Institute for Evolutionary Biology have pinned the initial shift in the spiders' range to the 1930s, occurring "in parallel with the onset of global warming."

The research, which sampled historical specimens from museum collections as well as contemporary spider populations, noted that after this initial change interbreeding allowed the spiders to gradually shift their natural temperature preferences and penetrate farther and farther north.

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Crawly, but not necessarily creepy: spiders invade Manhattan

John TImmer

NEW YORK CITY—If spiders send chills down your spine, then it's probably best if you didn't go anywhere near the American Museum of Natural History in New York. Not only are spiders on prominent display on the inside, but the front arch of the main entrance is now dominated by a giant, inflatable spider.

Of course, the people behind the exhibit would tell you that, if spiders give you the chills, there's no better place for you than inside the exhibit. There, amidst a fantastic collection of tarantulas and orb weavers, you can get a far better sense of just how spectacular these animals can be—and why they actually do most of us more good than harm.

People tend to assume spiders are insects, but they're actually of an independent lineage that dates back 300 million years, making us mammals look like youngsters. The exhibit itself includes a spider fossil that is about 100 million years old. There are now at least 43,000 distinct spider species recognized, and estimates are that we've only identified about half of them.

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Jumping spiders pounce using blurry green images of prey

A picture is two-dimensional and yet, when we look at it, we perceive depth. A number of visual cues tip us off to the relative distances of items in a photo. One of them is focus; if something is out-of-focus, we know it's not going to be the same distance away as something that appears sharp. To date, however, no animals were know to use focus as their primary means of estimating depth. But a paper in today's issue of Science provides some compelling evidence that this approach is the primary method used by jumping spiders.

Jumping spiders, as their name implies, don't capture their prey in webs. Instead, they make sudden leaps to reach and rapidly disable their targets. As you might imagine, that requires very accurate depth perception. Get the distance wrong and the spider could come up short of its prey, allowing it to escape.

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Researchers hack silkworm genome to get spidery silk

By a number of measures, spider silk is one of the toughest materials around. It's also light weight and (obviously) biocompatible. Unfortunately, it's also extremely hard to produce in any sort of usable quantity. Now, researchers have figured out a way that might help us make a lot more of something almost as good: they've engineered some DNA that encodes a hybrid of silkworm and spider proteins, and gotten silkworms to produce it.

We've cloned a number of spider silk proteins now, and managed to express them in everything from bacteria to goats. None of these methods end up making much in the way of protein, however, and the material that is made is difficult to purify and form into fibers. Spiders would seem like an obvious choice for making silk but they create a number of issues that we don't normally associate with manufacturing; as the authors put it, "territorialism and cannibalism preclude spider farming as a viable manufacturing approach."

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Researchers hack silkworm genome to get spidery silk

By a number of measures, spider silk is one of the toughest materials around. It's also light weight and (obviously) biocompatible. Unfortunately, it's also extremely hard to produce in any sort of usable quantity. Now, researchers have figured out a way that might help us make a lot more of something almost as good: they've engineered some DNA that encodes a hybrid of silkworm and spider proteins, and gotten silkworms to produce it.

We've cloned a number of spider silk proteins now, and managed to express them in everything from bacteria to goats. None of these methods end up making much in the way of protein, however, and the material that is made is difficult to purify and form into fibers. Spiders would seem like an obvious choice for making silk but they create a number of issues that we don't normally associate with manufacturing; as the authors put it, "territorialism and cannibalism preclude spider farming as a viable manufacturing approach."

Read the rest of this article...

Read the comments on this post