Scientists Discover Massive Spider Colony in Albanian Cave

Deep within the Sulfur Cave, located on the border of Albania and Greece, scientists have uncovered a remarkable ecosystem housing approximately 110,000 spiders. This extensive communal web, measuring over 100 square meters (1,000 sq ft), showcases a unique coexistence of two spider species, marking a significant discovery in the field of entomology.

The finding was made by an international team of researchers, including members from the Czech Speleological Society, during a wildlife survey conducted in March 2022. They were astonished not only by the sheer size of the multilayered web but also by the diversity of its inhabitants. The web is primarily composed of 69,000 Tegenaria domestica, commonly known as the common house spider, and 42,000 Prinerigone vagans, a smaller species known for its sheet webs.

A Unique Ecosystem

The Sulfur Cave is classified as a chemoautotrophic ecosystem, where life thrives without sunlight. Instead of photosynthesis, organisms here rely on chemosynthesis, converting chemical energy into organic matter. The cave’s environment is sustained by sulfur-oxidizing bacteria, which form thick white biofilms on the rocky surfaces. These microorganisms serve as the foundation for the food chain, being consumed by small invertebrates like midge larvae and isopods, which are then preyed upon by the spiders.

The cave’s warm, toxic stream maintains a temperature of approximately 26 °C (79 °F) and is rich in dissolved hydrogen sulfide, contributing to its distinct rotten-egg smell. This unique habitat not only supports the spider population but also eliminates typical food competition, allowing for a rare coexistence of species that would normally exhibit cannibalistic behavior.

Cooperative Living in Darkness

In a surprising twist, the researchers observed that the common house spiders, typically solitary hunters, formed a cooperative living arrangement within this extensive web. Thousands of individual funnel webs merged into a single structure draped along the cave walls. The spiders exhibited an absence of the expected aggression towards one another, a behavior that challenges previous understanding of spider ecology.

Additionally, the Prinerigone vagans spiders, which usually face predation from larger species, were found cohabiting peacefully alongside their larger counterparts. This unique dynamic raises intriguing questions about resource availability and competition in isolated ecosystems.

Genetic testing revealed that the spiders possess unique DNA distinct from populations found above ground, indicating they have evolved in isolation. Notably, the Tegenaria domestica spiders laid fewer eggs compared to their surface-dwelling relatives. Researchers believe this adaptation is linked to the cave’s low-oxygen environment and the absence of predators, reducing the need for larger clutches to ensure population stability.

The findings provide valuable insights into the adaptability of species in extreme environments and highlight the importance of resource abundance in shaping behavioral patterns. As researchers continue to explore these subterranean habitats, they uncover new perspectives on life’s resilience in the face of challenging conditions.

The research detailing these discoveries has been published in the journal Subterranean Biology, marking a significant contribution to the understanding of life in extreme environments. While the Sulfur Cave may not be a typical travel destination, it offers a fascinating glimpse into the complexities of life beneath the surface.