About 400 km above Earth, the International Space Station has housed not just humans but various critters including frogs, snails, ants, mice, swarms of flies, and over a million microbes.
Spiders were sent into space for the first time in July 1973. Two European garden spiders were sent to the then U.S space station called Skylab to see if they could build webs in zero gravity.
While the spiders could weave webs in space, researchers found that the webs were irregularly shaped.
They couldn't conclude if lack of gravity or lack of food and moisture made the spiders build deformed webs. Only five photographs could be taken of the webs.
In 2008, NASA decided to send spiders again. They sent two species, the labyrinth orbweaver as the main study species and another species of orb weaver as a backup.
They also sent small fruit fly colonies to provide continuous food for the spiders.
The backup spider escaped from its chamber and got into the main chamber. Now both the spiders in the same chamber started building webs resulting in random silk strands.
Also, the fruit fly larvae had unlimited access to food and their population increased more than expected.
In 2011, two golden silk orb-weavers were sent to the International Space Station. They planned to use four females for the experiment, two to be observed in space and two on Earth.
But researchers couldn't tell the sex of the juvenile spiders and two turned out to be male. Luckily there was one male and one female each on the ground and in space.
Under natural conditions, these spiders build asymmetric webs, with the centers closer to the top. They then stay on the top half of the webs with their head pointed downward. This way, gravity helps the spider rush down toward the prey caught in the web.
A new paper published in the journal Science of Nature has now noted that the webs built by spiders in space were quite symmetric. But when the light was on, they built asymmetric webs with the centre near the light source.