Why blind spiders live in the caves of Israel (5 photos)

Scientists have found spiders in 30 caves in Israel, which are in different degree lose their sight, or are completely blind. It turns out that this is understandable scientific explanation.





Specialists from Israel discovered several species in the caves funnel spiders Tegenaria, which are in various stages of loss vision. Scientists have noted that spiders living at the entrance to the cave have preserved vision - and those who live a few hundred meters deeper in the cave, have poor eyesight or are practically blind.



The phenomenon of adaptation by Charles Darwin immediately comes to mind. On In the Galapagos Islands, he discovered several species of finches. Some of them moved to neighboring islands and acquired many differences from others - so much so that they were divided into two different types. This observation has shown that such isolation leads to speciation.



Also with the spiders found in Israel. Differences between them were so large that they were divided into different types. Total scientists explored 30 caves. 26 species of Tegenaria spiders living in them accustomed to sunlight, had normal vision and lived near entrance, that is, they are troglophiles. The other 14 species lived further away, in complete darkness, losing sight or having weakened eyes - such organisms are called troglobionts. As a result, scientists identified 7 new species from those that live in complete darkness, and have strong differences from "sighted" relatives.



The researchers also analyzed the DNA of these spiders and traced their history throughout the area. They came to the conclusion that spiders, who have adapted to the conditions of the cave will no longer be able to live for it outside - they have finally adapted to the dark. When some species with the course of evolution climbed deeper into the caves, they there was literally no need to use the eyes and waste energy on vision. The results of the study were published in the publication Molecular Phylogenetics and Evolution.