Researchers discovered a massive spider web spanning 106 square meters inside a sulfur-rich cave on the border between Albania and Greece. The web, likely the largest spider web ever observed in nature, hosts a colony of roughly 69,000 Tegenaria domestica (common house spiders) and 42,000 Prinerigone vagans.
This marks the first documented case of cooperative colony formation between these two species, which normally live in isolation. The colony covers an area equivalent to a small city apartment, the members of the Czech Speleological Society, who have been surveying the cave since 2022 as part of an inventory of subterranean fauna, said.
Another remarkable finding is the genetic isolation of the cave-dwelling spiders compared to those of the same species living on the surface. The samples showed significant differences, suggesting evolutionary adaptation to the underground, toxic environment. Researchers believe that this combination of isolation and abundant resources drove the typically solitary spiders to develop communal behavior.
“Our findings reveal a unique case of facultative coloniality in a cosmopolitan spider species, likely driven by resource abundance within a chemoautotrophic ecosystem,” the researchers wrote in the journal Subterranean Biology.
