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Cave Orb Spiders Adapt Web Construction for Dark Environments
Orb-weaver spiders, recognized for their intricate circular webs, have modified their spinning techniques in subterranean habitats. These arachnids now craft what appear to be strategic tripwires to ensnare ground-based prey in the absence of light.
Orb-Weavers in Caves: A Shift in Hunting Strategy
Typically, orb-weavers are known for constructing spiral orb webs, designed to capture flying insects such as mosquitoes and beetles. These webs are often sparsely attached to external structures like tree branches. However, the European cave orb spider (Meta menardi) exhibits a different approach within cave systems. Research indicates these spiders reinforce their webs by using twice the amount of silk strands and anchoring them firmly to cave walls.
Tripwire Webs for Crawling Insects
According to Thomas Hesselberg from the University of Oxford, these modified webs function as sensitive tripwires. When ground-dwelling creatures inadvertently brush against the dense silk strands, the vibrations alert the spider to the presence of potential food. This adaptation suggests a specialized hunting strategy evolved for the unique conditions of cave environments, where airborne insects may be less prevalent, and terrestrial invertebrates become a more reliable food source.