The researchers estimated more than 42,000 Prinerigone vagans and some 69,000 Tegenaria domestica are living in the cave.
Credit: Subterranean Biology
A group of enthusiastic researchers found what might be one's worst nightmares -- the world's biggest spiderweb, home to over 110,000 spiders, spans an area of 1,140 square feet, and made in the absence of sunlight, with high hydrogen-sulfur gas levels in a cave on the Albanian-Greek border.
In their research published in the Subterranean Biology journal, the researchers called it "the first documented case of colonial web formation in these species." Their data confirmed the two dominant spider species inhabiting the cave, co-existing in a manner that stunned the scientists.
Lead author István Urák, in an interview with Live Science, said, "The natural world still holds countless surprises for us. If I were to attempt to put into words all the emotions that surged through me [when I saw the web], I would highlight admiration, respect, and gratitude. You have to experience it to truly know what it feels like."
Urák, who is also an associate professor of biology at Sapientia Hungarian University of Transylvania in Romania, detailed the group's findings in the journal published on October 17, that the large spider colony was identified mostly on a permanently dark part of the cave. The study pinpoints the areas "on the left bank of the sulfidic stream of Sulfur Cave."
Furthermore, the researchers estimated more than 42,000 Prinerigone vagans and some 69,000 Tegenaria domestica are living in the cave, naming the two species as the dominant specimens in this colony.
The spiders in the cave feast on non-biting midges, with them eating white microbial biofilms from sulfur-oxidizing bacteria in the cave. The biofilms are "slimy secretions that protect microorganisms against threats in their environment," as elaborated by Live Science. Such an environment is created as a sulfur-rich stream fills the cave with hydrogen sulfide, a stream created by the cave's natural springs, for the coexistence of the organisms.
Before this expedition, Czech Speleological Society's cavers were the first ones to discover the Sulfur Cave in 2022. Before Urák and his team visited the site, they analysed specimen collected by a team of scientists that visited the cave in 2024.