Space station spiders found a hack to build webs without gravity

Originally published at:


Reminds me of Guy Kawasaki’s UI guidelines for making drop shadows back in the early Macintosh years: assume the light is coming from the sun above and to the right(?) of the screen, then base shadows on buttons that were either out or pressed in based on that.


Welcome to our arachnid overlords.

(sorry @gadgetphile I did not mean that to be a response to your comment)


I keep editing this. It’s really a great read. The Introduction section illustrates many of the challenges they faced going back to the 1980s. Bascially, you signed up to be an astronaut, congratulations you’ve made it and now you’re a spider wrangler.

I’m not one of these spider scientists and this is all armchair, and I’ll admit odds are I’m under-thinking it and lots of studies have already established etc etc. But I’ll go anyway.

I think the real story here is that the spiders’ instincts kicked in to build webs without light to create the best odds of capturing fruit fly prey in a zero-light environment, AND utilized their instinctive understanding of prey behavior to adjust their webs accordingly in the presence of light.

Key observation: Spider’s back was to the lights when the lights were on. The tests were done with hatching fruit fly larvae. Newly adult fruit flies are attracted to light.

So, spider’s POV, thinking like the prey: In the absence of light, the prey could end up anywhere. Spreading out the web could yield a better chance at catching it. In the presence of light, prey may be more likely to believe that light to be an exit or a path towards food. Not as much grows in dark places as places with light. Where there is light, there is (edible) life for both the spider and prey. Therefore, the spider would have a better chance at snaring prey by concentrating the webbing closer to the light source. They also don’t necessarily know where the flies are coming from whereas on earth, the flies will hatch from fruit, more likely from fallen fruit, and light is predictably opposite of gravity. So a web above the ground is more likely to catch newly emerged fruit flies once the sun comes up.

I am not sure that in zero gravity they are orienting to up and down. But the behavior in gravity DOES have to do with “up” or “down.”

Webs built in normal gravity were all asymmetric, and there was no difference between webs whose web building had started in the night and those webs whose web building had started during the day ( U = 97.0, p = 0.38). A mixed model analysis with individual as a random factor gave the same conclusions, indicating that there was no difference between the spiders.

In that case, possibly the spiders know that light appears opposite of the gravitational pull, knowing that light will appear above and fruit flies will be drawn to it.

Here’s a funny one, emphasis added:

Closer analysis revealed that spiders in zero gravity tended to orient themselves downwards when the lights were on (median = 15° from vertically downwards) but showed no tendency to face in any particular direction when the lights were off (median near horizontally; Fig. 4). It is noteworthy that the spiders retained their previous orientation for as much as 1 h after the lights had been turned on or off, respectively (Fig. 5).

What does “downwards” mean? That there seems like gravitational bias. I think they are really saying “opposite the light source.”


The spirals of experimental webs built by Araneus diadematus (L.) in such a way were rounder and had a reduced vertical asymmetry, indicating that the spiders were missing gravity as a cue to build webs with their typical elongated and asymmetric spirals (Mayer 1952; Zschokke 1993, 2011).

Is this a certainty that this is what it’s indicating to us? Do we know how the same absence of cues effect the behavior of the fruit flies? Did spider webs created in these conditions capture fruit fly prey more effectively, less effectively or as effectively as identical circumstances in normal gravity?

I’m also wondering if there are studies of spiders in earth gravity or in slightly lower gravity where a light source has been placed shining from the source of gravity. Will they make webs that are oriented according to the gravity, or to the source of light?

In space, no one can hear you buzz.


The enemy’s gate is down.


I was thinking along the same lines, but how many generations of these spiders have lived with artificial light sources and how has that effected their web design and hunting habits


Can we all stop using the word “hack” when it’s really just “a new way to perform a task”

A hack is using an item for some task other than it’s original purpose


spider uses light in the absence of gravity to build its web. This is just a new way to perform a task.

spider uses a paperclip to open a lock. This is a hack because the spider found a new way to use a paperclip


Hear, hear!

It’s worse than that. The headline implies that spiders would have been completely unable to build a web without this special ‘hack’. Which is nonsense, of course.


So where were the Spiders?

Just a beer light to guide them.

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Awww… Poor Lucas!


From above and to the left of the screen - the ‘sunlight’ would be emanating from the Apple Menu at the top left corner of the screen.

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Cool! So they use the old surfer’s and scuba diver’s trick of orienting to bubbles (or in this case, light) with light = up and dark = down.


You want moon spiders? That’s how you get moon spiders!


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