World's Largest Spiderweb Found in European Cave

It may sound like something out of a nightmare, especially for arachnophobes, but scientists say they weren’t dreaming when they discovered a gigantic spiderweb that’s home to more than 110,000 arachnids inside a cavern along the border of Greece and Albania.

Credit: Marek Audy

The huge structure is set in total darkness and spans over 1,000 square feet. It’s one of the largest spider colonies ever documented, possibly the biggest in the world, researchers report in a paper published the journal Subterranean Biology.

Two species of spiders cohabit in this dark, murky world: Tegenaria domestica, known as the barn funnel weaver or domestic house spider, and Prinerigone vagans. They also found an “unusually dense” swarm of small midge flies in the cavern, which probably provide the main food source for the arachnids.

The team was surprised to find these spider species living in the cave, as they’re typically found on the surface. Beyond that, it’s one of the first recorded instances of the two species living together in apparent harmony. The scientists believe the T. domestica spiders are the primary architects and builders of the giant web, while P. vagans is simply living in it.

The researchers would have expected the much larger T. domestica spiders to eat the smaller P. vagans, but they think that the cave’s darkness is responsible for their apparent congeniality. This theory seems plausible given that P. vagans spiders tend to remain motionless until their own prey is within striking distance. Perhaps, they speculate, the T. domestica simply cannot see them.

Researchers are continuing to study the cave’s creepy-crawly residents. But in the meantime, they’re enjoying the fact that “the natural world still holds countless surprises for us."

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