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5 Crazy Things That Spiders Eat

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If you thought spiders only eat insects, think again. In recent years, scientists have discovered that small animals and other surprising food items are an important part of many spiders’ diets.   

1. Fish

Semiaquatic spiders such as Dolomedes facetus (above) occasionally kill and devour small fish, according to a new study in PLoS One. The study’s authors list more than 80 known cases, spread across every continent except Antarctica, where spiders have ambushed fish from the edges of ponds, lakes, rivers and swamps. The arachnids use their neurotoxic venom to subdue the fish, then drag them to a dry place to eat them. The chum are small—typically between one and 2.5 inches long—but on average they’re 2.2 times larger than the spider.

One interesting species, Argyroneta aquatica, constructs a dome-shaped web amongst water plants, and fills it with air from the surface. After the spider slays its aquatic prey, it brings the meal back to the dome to eat it.

2. Bats

Scientists have reported more than 52 cases of spiders eating small or juvenile bats with a wingspan of up to nine inches. In the majority of those cases, the bats accidentally get tangled up in webs—usually those of tropical and subtropical orb-weaving spiders, whose webs can be six feet in diameter or larger. But some species of tarantula have been known to stalk and attack bats on rare occasions.

3. Birds

There’s no indication that spiders are adapted to eat birds. In fact, a collision with a bird can cause significant damage to a spider’s web. But when life hands you lemons … wrap them in silk, liquefy their innards, and feast.

A 2012 paper catalogued 69 cases of birds getting trapped in spider webs, including 18 that had been mummified in silk for consumption by the spiders. (Many of these birds were rescued through human intervention.) The largest species recorded was a three-ounce Laughing Dove. Most of the other victims were hummingbirds. Here again, the culprits were almost always orb weaver spiders.

4. Snakes

Dinesh Rao/Flickr

That’s right—spiders can eat snakes. And if you don’t believe us, check out this horrifying video, or these images. In 1926, Canadian entomologist James Henry Emerton wrote a graphic description of how the tarantula Grammostola actaeon kills its slithering prey:

When a Grammostola and a young snake are put in a cage together the spider tries to catch the snake by the head and will hold on in spite of all efforts of the snake to shake him off. After a minute or two the spider's poison takes effect, and the snake become quiet. Beginning at the head, the spider crushes the snake with its mandibles and feeds upon its soft parts, some- times taking 24 hours or more to suck the whole animal, leaving the remains in a shapeless mass.

5. Plants

R. L. Curry

Of the world’s 35,000 or so spider species, only one is known to be herbivorous. The (mostly) vegetarian Bagheera kiplingi dines on leaf tips of the acacia shrub in Mexico and Central America. It uses its hunting kills to avoid the ants that colonize acacia … and occasionally dines on their larvae to supplement its diet.

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iStock // Ekaterina Minaeva
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Why Your iPhone Doesn't Always Show You the 'Decline Call' Button
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When you get an incoming call to your iPhone, the options that light up your screen aren't always the same. Sometimes you have the option to decline a call, and sometimes you only see a slider that allows you to answer, without an option to send the caller straight to voicemail. Why the difference?

A while back, Business Insider tracked down the answer to this conundrum of modern communication, and the answer turns out to be fairly simple.

If you get a call while your phone is locked, you’ll see the "slide to answer" button. In order to decline the call, you have to double-tap the power button on the top of the phone.

If your phone is unlocked, however, the screen that appears during an incoming call is different. You’ll see the two buttons, "accept" or "decline."

Either way, you get the options to set a reminder to call that person back or to immediately send them a text message. ("Dad, stop calling me at work, it’s 9 a.m.!")

[h/t Business Insider]