Spider webs with striking colors are not only attractive; Rather, their silk can be used as biological materials to regenerate nerves and help advance science. According to a new study on space spiders (Trichonephila clavipes), these intelligent creatures can adjust their direction based on light in the absence of gravity.
Scientists have done a lot of gravity experiments on spiders so far. In these experiments, the spiders were usually kept in a centrifuge, making their strands horizontally and spinning continuously to make the strands. A team of Swiss and US researchers say in a new article:
These observations and experiments show that gravity is an important criterion in the fabrication of spider webs; But they cannot answer the question of whether spiders can make a web under zero gravity, and in this case, how the zero gravity environment affects the completion of the web. These questions can only be answered by bringing spiders into a zero gravity environment.
This is not the first time spiders have been sent into space for research; But new research has achieved comprehensive results for the first time; Because previous experiments on spiders were not very effective. In 1973, two European garden spiders (Arenus diadematus) were sent to Skyleb, the first space station in the United States. The mission was part of NASA’s Skylab Student Experiment Competition. No pictures were taken of the strings and no food or water was given to the spiders; Therefore, irregularities were seen in their strings.
In the International Space Station (ISS) experiment in 2008, two species of spinning spiders were used: one for research and one in a separate chamber as a support species. This time the scientists fed the spiders fruit flies; But in the worst-case scenario, the backup spider escaped into the main chamber, and the two spider webs collided. As a result, the number of fruit flies had to double to control the population. Researchers say:
The larvae and cocoons of the fruit fly covered the window almost two weeks after launch. After about a month, one of the windows was completely covered and it was impossible to see the spiders.
Researchers tried their luck again in the 2011 experiment. This time there was no escape of the spider or the destruction of the photo or the explosion of the fruit fly. Instead, a picture of golden circular weaves was taken every five minutes; While the lights were turned on and off every twelve hours to simulate daylight. Although something unexpected happened (out of four spiders, two were found to be male), the results of a two-month experiment at the ISS were extremely successful.
The two spiders that were sent into space are stable in their low-gravity house The male spider appeared to have survived zero gravity for 65 days and survived even after returning to Earth. Meanwhile, the female spider made 34 strings and peeled it three times, which is a record; But the use of light in the new experiment led to a surprising discovery. Researchers believe:
Under normal gravity conditions, regardless of whether or not they use light, the spiders made asymmetrical strands and were housed in a downward-facing chamber; As a result, we found that gravity is the most important guide for spiders. Then, we came to the conclusion that visual stimuli for light can also act as a guide for orientation in the absence of gravity.
Under gravity, golden round spiders usually make their own asymmetrical webs and wait for prey in a downward direction. In space, the strings are more symmetrical, and if the light is in the opposite direction of the descent, the spiders can use it as a reference point to build their strings. Samuel Chowk“Biology at the University of Basel,” he says.
We did not think light would play a role in orienting the spiders in space. We were very lucky that the lamps were installed at the top of the compartment, not the other side. Otherwise, we could not detect the effect of light on the symmetry of the fibers at zero gravity. It is a surprising phenomenon that spiders use a support system to build their own fibers in the absence of gravity; Because they had not previously been exposed to a gravity-free environment during their evolution.
This research in The Science of Nature Released.