Spiders specially taken to the International Space Station for experiments have found a way to build a web without gravity.
These spiders were specially brought on board to see how space conditions affect web building. The spiders have actually been flying into space for over a decade, but now there seems to have been a breakthrough in our understanding of how they build webs in microgravity.
In the wild, trichonephile spiders build asymmetric nets with a hub at the top edge of the net and they always orient themselves downwards when sitting on the hub, waiting for prey. Because these asymmetries are thought to be related to gravity, the authors of the experiment expected spiders without gravity to build symmetric nets and show random orientation while sitting on the hub. It turned out that most, but not all, of the networks built in weightlessness were indeed quite symmetrical. Closer analysis showed that the nets constructed when the light was on were more asymmetrical (with the hub next to the light sources) than the nets constructed when the light was off.
In addition, the spiders exhibited random orientation when the light was off, but looked away from the light when it was on. Scientists concluded that, in the absence of gravity, it is the direction of light that may serve as a guide for spiders during web construction and when waiting for prey at a node.