If you’re an aspiring astronaut you might want to review your feelings towards spiders before sending an application, as a recently published study tasked scientists with taking some eight-legged friends to the International Space Station. I expect even some spider fans might agree that having quite so many legs flailing around in zero gravity isn’t an ideal working environment, but the research published in the journal The Science of Nature revealed novel and surprising insights into what influences how a spider constructs their web.
On Earth, spiders build asymmetrical webs with the center closer to the top of the web than the bottom. This is beneficial as when scurrying to catch some food the spiders are working with gravity rather than against it. When spiders are at rest, their heads are pointed towards the ground for the same reason. So, if you take away gravity as an environmental factor to work with or against, what does a web look like?
To find out, astronauts took some spiders (arachnauts, if you please) to the ISS. Their subjects were two juveniles, Trichonephila clavipes, spiders who were observed for two months building webs in zero gravity. Their efforts were photographer every five minutes during this time and compared against the same data collected about two spiders in nearly the exact same experimental conditions except that they were down on Earth.
Like most spiders under the influence of gravity, the Trichonephila spiders on Earth built asymmetric webs with the center at the top, and face down towards the ground at rest. Given the logical influence of gravity on these spiders, it was hypothesized that the zero-gravity spiders would build symmetrical webs and orientate themselves in random ways.
Their assumptions were partly correct, as the space spiders were mostly building symmetrical webs. However, closer analysis of their efforts revealed that light had an influence on their web making, as when the light was on the webs were more symmetrical than when it was off. Orientation was also affected by the light, as the spiders were orientating randomly when it was off and faced away from the lights when they were on.
“We conclude that in the absence of gravity, the direction of light can serve as an orientation guide for spiders during web building and when waiting for prey on the hub,” wrote the researchers.
While a fascinating study, what’s perhaps more entertaining is that this wasn’t the first time such an experiment had been attempted however the first try was something of a disaster. Back in 2008, one Metepeira labyrinthea spider was taken to the ISS to be the lead with a backup Larinioides patagiatus spider as a reserve in case something went wrong. And, oh boy, did it.
The reserve spider managed to escape from its storage chamber and ran loose in the experimental chamber with the other spider which couldn’t be opened for safety reasons. With little space, the two spiders created messy webs and were routinely in each other’s way. To make matters worse, the flies the crew stocked up on to feed the spiders were reproducing at a much more rapid rate than expected. Their larva also managed to escape into the experimental chamber and as more and more babies were created the spiders became harder and harder to see. Eventually, one month later, the spiders were effectively buried alive in fly larva.
Incredible to think that the same people behind getting humans to the moon struggled to build maggot-proof chambers. It's reminiscent the opening scene of Jurassic Park where the same funding which resurrected dinosaurs couldn't stretch to a remotely operated container for its most deadly species.