While often perceived as silent, spiders produce a variety of sounds, many imperceptible to human ears. These sounds reveal a complex world of arachnid communication.
The Unexpected World of Spider Sounds
Spiders primarily communicate through vibrations, which travel through solid surfaces, leaves, or silk. Their sensory organs detect these subtle movements, allowing them to interpret messages. Many spider sounds operate on wavelengths requiring specialized equipment, like laser vibrometers, for detection.
Specific Sounds Spiders Produce and How They Are Made
Spiders employ several physical methods to generate sounds. One prevalent method is stridulation, where spiders rub two rigid body parts together, much like a violin bow across a string. This action produces sounds ranging from chirping to hissing or buzzing, depending on the species. For instance, some tarantulas create a hissing noise by rubbing specialized bristles on their limbs or fangs, often as a defensive display. Wolf spiders also stridulate, using organs on their pedipalps or legs to generate sounds described as purring or buzzing.
Another common method is drumming or tapping, where spiders percussively strike a surface with their legs or pedipalps. This creates vibrational signals that travel through the substrate. Male wolf spiders, for example, produce rhythmic drumming patterns on the ground using their pedipalps for communication. These percussive signals are substrate-borne vibrations, detected by specialized sensory organs like slit sensilla on their legs.
Web-building spiders leverage their silk to transmit vibrations. By plucking or vibrating web strands, spiders generate ripples that travel across the structure. This allows them to send and receive information. Spider silk’s unique properties enable it to transmit vibrations across frequencies, effectively turning the web into an extension of the spider’s sensory system.
Why Spiders Make Noise
The sounds spiders produce serve various biological functions, primarily centered around survival and reproduction. Courtship and mating are significant purposes. Male spiders often use drumming, tapping, or stridulation to attract potential mates, signaling their presence and species identity. For example, the male “purring” wolf spider (Gladicosa gulosa) uses vibrations on leaves to create airborne sounds that attract females, with the success of this ritual depending on both spiders being on a surface that vibrates easily. These signals can also convey information about the male’s quality and receptiveness, helping to prevent misidentification or aggression from the female.
Beyond courtship, sounds also play a role in defense and warning. Some spiders produce audible hissing or buzzing sounds to deter predators or perceived threats. Tarantulas are well-known for their defensive stridulation, where the hissing sound, often accompanied by a raised posture, aims to warn off potential attackers. This serves as an acoustic warning system, indicating a spider’s readiness to defend itself.
Sounds can also be involved in territoriality, helping spiders establish or defend their living spaces. While less frequently discussed than courtship or defense, some vibrational signals may indicate occupancy or warn rivals to stay away. The complexity of these sound-based interactions highlights the sophisticated communication systems present in the spider world, even if largely unnoticed by humans.