documented<\/a> an extraordinary colonial spider community deep inside a sulfur cave on the Albania\u2013Greece border, home to tens of thousands of spiders living together in what may be the world\u2019s largest known spider web.<\/strong><\/p>\nThe multilayered web, stretching across more than 100 square meters along a cave wall near the entrance, supports a mixed colony of approximately 69,000 Tegenaria domestica<\/strong> (domestic house spiders) and 42,000 Prinerigone vagans<\/strong>. This marks the first recorded instance of colonial web-building behavior for both typically solitary species.<\/p>\nDiscovery in a Toxic Environment<\/h3>\n
The remarkable find was made in 2022 by members of the Czech Speleological Society while surveying underground biodiversity in sulfur caves. The harsh subterranean environment features complete darkness and high concentrations of toxic hydrogen sulfide gas.<\/p>\n
Scientists used DNA analysis and morphological studies to confirm the two species. They estimated the colony size by counting funnel webs in sample sections and extrapolating across the measured 106-square-meter web-covered area.<\/p>\n
Chemoautotrophic Food Chain<\/h3>\n
The spiders thrive thanks to a self-sustaining food web powered entirely by sulfur-oxidizing microbes inside the cave. These microbes support vast numbers of chironomid flies (non-biting midges), which emerge from cave streams and become easy prey trapped in the extensive web. Stable isotope analysis confirmed the spiders rely on this internal cave ecosystem rather than external insects.<\/p>\n
Genetic Adaptation and Colonial Behavior<\/h3>\n
Genetic testing revealed that the cave-dwelling spiders are distinct from surface populations of the same species, indicating long-term isolation and adaptation to the extreme environment. Researchers believe the combination of genetic divergence and the abundant, reliable food source has driven these normally solitary spiders to form this unusual \u201carachnid megacity.\u201d<\/p>\n
The study, published in the journal Subterranean Biology<\/em>, describes it as a unique case of facultative coloniality in a chemoautotrophic cave system.<\/p>\n\n\u201cOur findings unveil a unique case of facultative coloniality\u2026 and provide new insights into the adaptation and trophic integration of surface species in sulfidic subterranean habitats,\u201d the authors write.<\/p>\n<\/blockquote>\n
The discovery highlights how extreme environments can reshape typical spider behavior and offers new understanding of subterranean ecosystems.<\/p>\n
This could represent one of the largest cooperative spider structures ever observed on the planet. Further research may reveal more about how these colonies maintain stability in such a challenging habitat.<\/p>\n