The study “has extensive scientific implications for uncovering the evolution of speciation in caves and the historical, geographic and climatic processes that occurred in Israel,” the Hebrew University said in a statement.

“In this study we sought to understand the evolutionary relationships between funnel web spiders (Agelenidae, Tegenaria) with normal eyes that are found at the entrance to the caves in Israel, and those that are deep in the cave and are pigment-less, eye-reduced and even completely blind, said Hebrew University doctoral student Shlomi Aharon, who led the study under the guidance of Dr. Efrat Gavish-Regev and Prof. Dror Hawlena.

The spiders were collected from caves in the Galilee and central Israel, after which they were taken to labs, where the scientists extracted their DNA and conducted more tests.

“Among the spiders we found, five were unique to different caves, and the two other species were found in several caves,” said Gavish-Regev, from Hebrew U’s National Natural History Collections.

“One of the surprising findings in the study shows that the new species are evolutionarily closer to species from caves in Mediterranean areas in southern Europe, than to species living in close proximity to them at cave entrances in Israel,” she said.

Two of the newly identified species are blind, and the other five are classified as eye-reduced.

The researchers suggest they adapted to the underground habitat after or simultaneously with the extinction of the ancestor species from which they evolved, which lived outside of caves and became extinct due to historical climate changes in the region.

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