Airborne silk motion recorded by laser vibrometer. The diameter d and length L of the spider silk are 500 nm and 8 mm, respectively. The airborne acoustic signal contains human voice, low-frequency (100–700 Hz) wing beat of insects, and high-frequency (2–10 kHz) song of birds. A shows the waveform of silk motion. B shows the frequency-dependent spectrogram of silk motion. An audio of the airborne silk motion is also included in this movie. The silk motion clearly captures the airborne signal.