A study has found that spiders use light as a reference point when they rotate their nets under the microgravity found at the International Space Station (ISS) in Earth’s orbit.
In their natural habitat on the surface of the planet, our eight-legged friends weave slightly asymmetrical webs – their center is slightly closer to the top edge.
The spider – sitting at this focal point – can be more likely to travel in the web towards the captured prey because they are moving faster in the direction of gravity.
However, it is not clear how rotation in a low-gravity environment will affect the web spinning process – so NASA sent the spiders to the ISS for investigation.
Although initially thought to be a ‘simple’ experiment to attract the attention of American middle school students, the results have proven to be unpredictable and far-sighted.
Spiders use light as a reference point when spinning webs in the International Space Station’s (ISS) micro-gravity orbit around the Earth, a study has found. Image, ISS
In their first study in 2008, NASA sent two brave ‘monarchs’ to the ISS – one with a complex orbit (‘Metebora labrindia’), the main object, and the other with a backup of Lorrinoides pathogenesis.
Unfortunately, the test did not go as planned. First, one of the spiders exploded from its cage into its fellow city – meaning two spiders were able to spin the chaotic mess of nets in an unexpectedly shared space.
In addition, flies were brought in as food for spiders that grew at unexpected speeds – eventually finishing coating the window into the test cage, and the arachnids were completely hidden after a month.
On a second voyage in 2011, Paula Cushing, a biologist at the Museum of Nature and Science in Denver, and colleagues sent instead two spiders of the same species – the trichomoniasis clavips, the ‘golden silk ball-weaver’ – in separate cages.
Two more gold silk ball-weavers were observed in cages on earth to act as a control for comparison. Three cages were fitted to each cage. Sometimes, spiders were allowed to spin their webs under lanterns, other times in the dark.
The team recorded a total of 14,500 still images of spiders rotating their webs, disposing of them and rotating new ones – from which they were able to read a total of 100 different web configurations.
The team found that the gravitational and dark rotating webs are more symmetrical than those on the Earth’s surface – the center of each is closer to the actual center.
In addition, spiders in these conditions do not always point their heads at their webs – ready to drop – and position themselves as they do on earth.
However, when working under lanterns, the researchers noted that the spider webs turned asymmetrically – the centers of the webs were close to light, and the arachnids pointed themselves out of the lights.
‘We would not have guessed that light would play a role in looking at spiders in space,’ said Samuel Choke, a paper writer and biologist at the University of Basel.
‘We were very lucky that the lights were attached to the top of the room and not on different sides,’ he explained.
‘Otherwise, we would not be able to detect the effect of light on the symmetry of the nets at zero gravity.’
In their first study in 2008, NASA sent two brave ‘monarchs’ to the ISS – one with a complex orbit (‘Metebora labrindia’), the main object, and the other with a backup of Lorrinoides pathogenesis. Unfortunately, the test did not go as planned. First, one of the spiders exploded from its cage into its fellow city – i.e. two spiders ended up spinning the chaotic web of webs, pictured
The team found that the nets rotated under microgravity and darkness and ended up more symmetrical than the surface of the earth (as in the picture, the lights were turned on again). In addition, spiders in these conditions do not always point their heads at their webs – ready to drop – and position themselves as they do on earth.
The researchers noted that when working under lanterns, spider webs turned asymmetrically – the centers of the webs were close to light, and arachnids pointed themselves out of the lights.
“It’s amazing that spiders have a backup system for such an orientation because they were never exposed to an environment without gravity during evolution,” Dr. Shocke said.
On the other hand, he explained that since spiders are constantly in motion while the web is spinning, the second way to look at themselves may be to reap its benefits.
The full findings of the study were published in the journal The Science of Nature.