Scientists from NASA have found that spiders use light as an additional source of information for navigation. They begin to pay attention to it in zero gravity.
Researchers from NASA carried out experiments with spiders. They noticed that predators could create asymmetrical webs on Earth, the center of gravity of which is often shifted towards the top edge. At the same time, during rest, spiders are usually located head down – this way, they move faster towards gravity to get to their prey. Therefore, scientists wanted to test how spiders would navigate in an environment where there is no gravity.
For this purpose, they sent spiders to the International Space Station (ISS). These were four spiders of the same species – Trichonephila clavipes, two of them went into space, and two were kept in the same conditions on Earth, but the laws of gravity continued to work on them.
It turned out that cobwebs in zero gravity are more symmetrical than in space. Simultaneously, the spiders themselves were located differently from on Earth, and did not always keep their heads in the direction of gravity. Later, researchers accidentally noticed that the spiders weave webs just like on Earth if the ISS lights are on.
“We would not have guessed that this light plays a role in orienting spiders in space,” said the researchers from NASA. “We were fortunate that the lamps were attached to the top of the experimental chamber and not from different sides. Otherwise, we would not understand how much light affects the symmetry of the web under zero gravity conditions. ”
The images’ analysis also showed that the spiders stopped in their webs in an arbitrary position when the light was turned off, but oriented downwards when the light was turned on. So scientists realized that spiders use light as an additional means of orientation. Previously, researchers assumed that light played no role for them.