Researchers have discovered more than 111,000 spiders living in the world's largest web, deep inside a pitch-black cave on the Albanian-Greek border.
According to the study, published Oct. 17 in the journal, the “unusual” colony appears to be a colossal web in a perpetually dark area of the cave. Underground biology.
The web stretches 106 square meters along the wall of a narrow, low-ceilinged passage near the cave's entrance. The researchers noted that it is a mixture of thousands of individual funnel-shaped tissues.
Web Map – https://subtbiol.pensoft.net/
It is the first evidence of colonial behavior in two common spider species and likely represents the largest web in the world, said lead study author István Urak, an associate professor of biology at the Hungarian Sapientia University of Transylvania in Romania.
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“The natural world continues to hold countless surprises for us,” Urak told Live Science via email.
“If I tried to put into words all the emotions that overwhelmed me [when I saw the tissue]I would emphasize admiration, respect and gratitude. You have to experience it to truly understand what it's like.”
Where is the colossal colony of spiders?
The spider metropolis is located in the Sulfur Cave – a cave with a sulfuric acid cavity formed as a result of the oxidation of hydrogen sulfide in groundwater.
While researchers have discovered new information about the spider colony at Sulfur Cave, they weren't the first to see the giant web. Speleologists from the Czech Speleological Society discovered it in 2022 during an expedition to the Vromoner Canyon. A team of scientists then visited the cave in 2024, collecting samples of webbing, which Urak analyzed before setting off on his own expedition to Sulfur Cave.
Spider in a cave – https://subtbiol.pensoft.net/
This analysis showed that the colony was inhabited by two species of spiders: Tegenaria domesticaknown as the barn spider or house spider, and Prinerigonian Vagans.
During a visit to the cave, Urak and his colleagues estimated that there were about 69,000 specimens of T. domestica and more than 42,000 specimens of P. vagans living there. DNA analysis for the new study also confirmed that they are the dominant species in the colony, Urak said.
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According to Urak, the spider colony at Sulfur Cave is one of the largest ever recorded, and the species involved had not previously been known to congregate and cooperate in this way. T. domestica and P. vagans are common near human habitations, but the colony represents “a unique case of two species coexisting in the same tissue structure in such huge numbers,” he said.
“It is important to preserve the colony despite the problems that may arise due to the location of the cave between two countries,” Urak added.
Meanwhile, researchers are working on another study that will reveal more details about the inhabitants of Sulfur Cave.
