How the Jumping Spider Sees Its Prey
November 6, 2018 10:28 AM   Subscribe

Researchers looked deep into the eyes of a predatory spider to learn what it was looking at. "But as accurate as the main eyes are, they only see what is in front of them. If they had to find prey, it would be like using a narrow flashlight beam to explore a dark room. Not very efficient."
posted by dhruva (34 comments total) 30 users marked this as a favorite
 
Oooh, my favourite kind of spider!!!
posted by Pendragon at 10:34 AM on November 6 [3 favorites]


It was nice of them to note that the spiders aren't harmed, I was worried.
posted by Pendragon at 10:36 AM on November 6 [15 favorites]


The story has a buried lede: SPIDER HATS.

The researchers were able to conduct the experiment without harming the spiders. They affixed a Dr. Seuss style hat to the top of the spiders’ heads with wax, and that hat was attached to an apparatus to keep them in one place.
posted by mandolin conspiracy at 10:41 AM on November 6 [17 favorites]


I'll take "Arachnid Haberdashery" for $500, Alex.
posted by mandolin conspiracy at 10:42 AM on November 6 [10 favorites]




Wow. Evolution has solved "how do I make this creature see" in a whole lot of different ways over the eons, but damn, that's a cool way to do it.
posted by Making You Bored For Science at 10:47 AM on November 6 [2 favorites]


I collaborated with this group in Umass and have used this equipment, so if anybody needs details, I can explain
posted by dhruva at 10:50 AM on November 6 [20 favorites]


I collaborated with this group in Umass and have used this equipment, so if anybody needs details, I can explain

*pulls up a chair*

Go for it!
posted by mandolin conspiracy at 10:55 AM on November 6 [6 favorites]


If you like jumping spiders, I can highly recommend the book Children of Time by Adrian Tchaikovsky, which has a lot of spider POV time.
posted by foxfirefey at 10:56 AM on November 6


Please do, dhruva! I do eyetracking research in humans, and have bumped into it in mammalian models, but spider eyetracking is way outside my own research wheelhouse, and is deeply cool.
posted by Making You Bored For Science at 10:57 AM on November 6 [5 favorites]


They affixed a Dr. Seuss style hat
I thought the news that the Deadwood movie has started shooting was going to be the most delightful thing I read today, but I was wrong.
posted by ricochet biscuit at 11:05 AM on November 6




A year or so ago, some astronomers on Twitter were complaining about a spider infestation in their office. This led to experiments with laser pointers, which led to talking to a spider research lab, which led to two fun facts about spider vision:
Jumping spiders can resolve the moon, and maybe even some craters
and
Ogre-faced spiders can observe the Andromeda galaxy.
posted by miguelcervantes at 11:31 AM on November 6 [10 favorites]


It was nice of them to note that the spiders aren't harmed

I'm sure she wasn't unnecessarily mean to the spiders, but she did stick big gobs of orange paint in their eyes (1:24).
posted by pracowity at 11:36 AM on November 6 [2 favorites]


I hope that was removable paint, pracowity.
posted by Pendragon at 12:10 PM on November 6


Yep that was removable paint, it just flakes off
posted by dhruva at 12:16 PM on November 6 [5 favorites]


How old can these spiders get in the wild and do the spiders used in this experiment reach that age ?
posted by Pendragon at 12:20 PM on November 6 [1 favorite]


So the outer eyes are kind of like wide-angle and the inner eyes are telephoto?
posted by RobotHero at 12:21 PM on November 6


Pendragon: How old can these spiders get in the wild and do the spiders used in this experiment reach that age ?

They live around six months, generally they live longer in the lab because usually they die off during the winter

So the outer eyes are kind of like wide-angle and the inner eyes are telephoto?

Exactly, but really wide angle. See this figure for an illustration of fields of view. Inner eyes have colour vision as well.
posted by dhruva at 1:34 PM on November 6 [6 favorites]


I work on predator prey interactions, and in particular between tephritid flies and jumping spiders. So these flies do an elaborate wing display (something like this )in front of the spider, and if they do this display there's a 80% chance they escape attack. I've been trying to figure out why this works, and why this display works only on jumping spiders. So I took videos of the flies displaying and ran them through the eyetracker at UMass, and it seems that when the fly does a display, the spider has a harder time tracking the fly, whereas if it sees a fly walking the tracking is more accurate. Basically till now, people have assumed that the display works because the fly wings can mimic jumping spider leg patterns, but I'm working on the theory that it's a sensory bias in the spiders because they are very sensitive to motion.
posted by dhruva at 1:41 PM on November 6 [15 favorites]


I'm sure she wasn't unnecessarily mean to the spiders, but she did stick big gobs of orange paint in their eyes (1:24).

This was what my undergraduate work was like, come to think of it--I was working on fly courtship, but there really isn't another good way to blind small arthropods besides paint.

My flies also removed the paint, which made things difficult during my first pass using metallic sharpie ink--I had gotten all manner of little colors and spent an enthusiastic afternoon carefully daubing paint over their little faces and being excited to be running my experiment. I was somewhat dismayed in the morning when I geared up to make my crosses and spotted a vial full of flies with clean red eyes and translucent, happily enlarged metallic multicolored bellies: they had, overnight, scraped off all the paint and eaten it outright.

It took some work to find a paint that could keep flies blinded for the 48 hours I needed them to stay blind for.
posted by sciatrix at 1:52 PM on November 6 [16 favorites]


As explained in Jumping Spider Vision, the lenses of their large front eyes (and other smaller eyes) are fixed in their 'face' and cannot move. To gain better resolution and stereo binocular vision, their internal eye cones (behind the lens, with retina at the small end) move independently inside the spider's cephalo-thorax.

The Jumping Spider Eye Movement video shows the eye cones moving: the darker the eyes appear, the more directly the camera is looking straight into the retina(s). You can also see the eye cones through the spider's brightly lit translucent shell.

More about Salticid's unique vision at Spider Vision Made Clear and Wikipedia.
posted by cenoxo at 3:55 PM on November 6 [5 favorites]


And — because they can see so well — don't forget about jumping spider hand jive and courtship displays.
posted by cenoxo at 4:07 PM on November 6 [2 favorites]


Per miguelcervantes' link above, the Bea Leiderman and Yellow amycine jumping spider, Reserva Canadé, Ecuador videos clearly show jumping spider eyes scanning back and forth. From a fly's POV, it's a little unnerving to have a spider checking you out...
posted by cenoxo at 8:44 PM on November 6 [4 favorites]


Maybe the flies are mirroring the motions of the spiders eyes with their wings; there was something about the independence of the motions of the two wings, the way they went smoothly back and forth, and sometimes circled that reminded me of the way the spiders were moving their eyes. If the flies can see the motions of the spider's eyes, they could move one wing in sync with each of the spiders eyes.

That would really confuse any algorithm which was gauging distance of a nearby object from the way it moved relative to background when the observing eye moved.
posted by jamjam at 12:26 AM on November 7


jamjam: Maybe the flies are mirroring the motions of the spiders eyes with their wings

Forgot to mention that the flies do this display to other flies as well. I doubt the flies can see that well to be able to see the motion of spider eyes, but we have very little information about the visual acuity of these flies.
posted by dhruva at 6:32 AM on November 7 [1 favorite]


Yes, the video I watched of the flies' movements was apparently a mating dance, but I guess I took it for granted that display of a crucial predator evasion strategem could readily make its way into a mating dance.
posted by jamjam at 6:50 AM on November 7


> Jumping spiders can resolve the moon, and maybe even some craters
YOU GUYS, SPIDER TWITTER HAS FOUND US! Please, tell us everything, you've got a very curious group of astronomers over here :D...
I love this thread!
posted by homunculus at 9:29 PM on November 7


I live in one of those housing developments that real estate investors plop down in rural areas when the descendants of farmers have moved to the city and don't want to deal with ancestral land. As such, we're surrounded by active farms, marshes, and nature is all around.

Especially the bugs.

A city boy myself, I struggled for months with the ever-present distractions of gnats, ants, mosquitoes, and both kinds of cockroaches (the gigantic flying ones and the multi-sized swarmy ones). They could not all be smashed or poisoned or ignored. Our saviors have been two-fold: a half-dozen itinerant geckos and an army of small black jumping spiders. The geckos are silly and noisy and skittish, while the jumping spiders are stone cold killers.

Some hang out in small groups near the doorjambs and window screens, assassinating flies and gnats that try to get in. Others roam the walls and ceilings solo, pausing to stare us humans down when we pass in sight. It's eerie, to be under the gaze of such an uncanny life form.

I am protective of them. I rescue them from drowning in the sink and will go to John Ritter-esque lengths to avoid stepping on them. I call them "Spiderbro", as in - "Keep up the good work, Spiderbro!" Once one of them chased a mouse cursor across my laptop screen for five minutes before becoming disinterested. I love them. And their awesome, talented eyes.
posted by Enkidude at 10:49 PM on November 7 [3 favorites]






Warning for people: JW's link is spiders in people's ears. So we're clear.
posted by vibratory manner of working at 7:01 PM on November 9 [1 favorite]


It's ONE spider, and it's super adorable, and neither patient nor doctor is particularly fussed about it. I figure anybody who's made it this far into a thread about spider anatomy won't be too squeamish.
posted by Johnny Wallflower at 9:11 PM on November 10


I'm fine with spider anatomy as long as it stays outside of human anatomy.
posted by RobotHero at 7:38 AM on November 11


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