Spiders are capable of building typical webs in microgravity, provided they have access to a light source, according to new research published in Science of Nature. In the absence of gravity and therefore an up and down feeling, a light source provides a frame of reference for spiders. When a light source is available, spiders weave their normal asymmetrical webs and wait for their prey near the top. However, without light, they build symmetrical webs, which is not normal behavior. It is a surprising discovery *that highlights the relatively unimportance of gravity for spiders when they weave their webs.
(*my comment: don't be so sure, if gravity is what binds everything in creation)
The species chosen for the 2011 spider experiment is the golden silk orb weaver or Trichonephila clavipes. Cushing and Zschokke designed an experiment in which two spiders would build their webs in separate test chambers on the ISS, while two spiders were kept in identical habitats on the ground to serve as a control group .[...]It turns out that spiders, when working in microgravity, tend to weave webs that are significantly more symmetrical than those built on Earth. In addition, the shafts were placed closer to the center of the webs and the spiders did not always keep their heads down.
But this was not the case in all areas. Some webs exhibited a surprising degree of asymmetry, especially for those "whose construction had begun when the lights were on, suggesting that light replaced gravity as an orientation guide during web construction," according to the paper. In addition, the light also provided a reference for the spider in terms of its position on the web (by top, the researchers mean the top of the habitat).
Interestingly, access to a light source was not even considered as a factor in the experiment.
"We would not have guessed that light would play a role in the orientation of spiders in space," Zschokke said in a statement from the University of Basel. "We were very lucky that the lamps were placed on top of the camera and not on several sides. Otherwise, we would not have been able to discover the effect of the light on the symmetry of the zero-gravity networks.