Spiders on Earth have web-making down to a science, but not so much in space. They get disoriented without gravity.
Apparently spiders begin spinning their webs by dropping down from above and attaching anchor lines. Difficult to do sans gravity. The spider then typically sits on the upper-third of the web, facing down, waiting for prey.
Scientists say they have conducted incredibly annoying lab experiments (for the spiders) on the ISS to see how they would cope when spinning webs in zero gravity.
“What we found is that if a spider in space has no clue from gravity and no light, so that it has no idea what’s up and down, they’ll face in any random direction when they sit on the web,” Samuel Zschokke, a research fellow at the University of Basel in Switzerland, whose main research interest is spider webs, told Digital Trends. “As a result, the web is no longer asymmetric, it’s pretty much symmetric.”
Spider commonly spin asymmetrical webs on Earth with the lower part of the web capture area larger than the upper. Without any gravitational guide, the asymmetry does not occur.
However, spiders will substitute a light source for gravity in the same way they would normally head toward the pull of gravity. On Earth, spiders do not require light to build webs. In essence, they swapped out one sensory reaction (if gravity counts as a sensory reaction) for another.
“They have this way of compensating for the loss of gravity by using light,” he said. “That’s something we did not expect. Because why should any animal which has always lived in a gravity environment like Earth be able to compensate for a lack of gravity with something else?”
The results of the study, albeit annoying for the spiders, has provide valuable information on how living organisms can adapt to a zero-gravity environment.
“With more and more interest in long-term space exploration and living off-planet, studies like these can help inform how to keep living organisms healthy in space and how they might adapt to space,” Countryman said. “The next steps would be to repeat the experiment, but with larger habitats that are large enough for this particular type of spider to build a web that is closer in size to the ‘normal’ size that would be spun on Earth. It would also be of interest to examine more in-depth how the light cues the spider’s behavior in the absence of gravity.”