Scientists Discover Sneaky Spider That Fools Predators

Jul 13, 2017
Originally published on July 13, 2017 2:27 pm
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KELLY MCEVERS, HOST:

Rule number one in nature - find a way not to get eaten. You can run, fight or hide. Or you can look or move like something that tastes horrible. Now it seems like a type of jumping spider is taking that latter rule to the extreme. NPR's Christopher Joyce reports on a pretty cool discovery.

CHRISTOPHER JOYCE, BYLINE: Paul Shamble was watching a certain kind of jumping spider crawl around in the New York woods one day. But suddenly Shamble realized they were walking funny.

PAUL SHAMBLE: They really move like ants.

JOYCE: Why would a spider walk like an ant? They're very different. As an evolutionary biologist, Shamble figured it might be a form of mimicry. Many insects copy the shape or coloration of other often-poisonous insects. It fools predators. And ants definitely don't taste good. They're full of powerful chemicals, whereas jumping spiders, Shamble claims, taste just fine. He took the spiders back to the lab and filmed them. Their bodies did mimic the ant shape, but it was their walk that really stood out.

SHAMBLE: We found that the ant mimics walk these really, really winding paths.

JOYCE: And that's how ants walk when following a chemical trail left by their ant mates. And these spiders don't just walk the walk. They have another trick.

SHAMBLE: They hold up their front pair of legs off the ground and hold them out in front of their heads. And they look convincingly like antennae.

JOYCE: Spiders don't have antennae. Proof of any pudding of course is in the eating. So Shamble made animations of regular jumping spiders as well as these ant-mimicking ones and then invited big, predatory jumping spiders - the kind that eat smaller spiders - to watch the animations on an iPhone.

SHAMBLE: The big jumping spiders will happily attack an animation of a typical jumping spider.

JOYCE: But they left the ant-mimicking spiders alone. Shamble, at Harvard University, published the results in the Proceedings of the Royal Society B. He says the spider looks and acts so much like an ant...

SHAMBLE: It sort of makes you wonder, if you look like an ant and you walk like an ant, do other parts of your life become ant-like also?

JOYCE: That's the human perspective. The ants probably know it's a spider. Christopher Joyce, NPR News.

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