Title: Sounds of the Spiny Lobster <i>Panulirus argus</i>
Abstract: Panulirus argus generates three types of sound and each is composed of pulses that are approximately symmetrical about peak points. The distinguishing features of these sounds are average pulse duration, average interpulse duration, pulse rate, average pulse amplitude, temporal pattern of average amplitude, and spectral composition of pulses. Two of the P. argus sound types—what we call the “popping series” and the “flutter”—are new to the literature. They apparently constitute what previous investigators designated a “slow rattle.” The third type of P. argus sound—the “rasp”—was found to conform in most respects to a sound previously identified by the same name. While the communicatory function of the “rasp” is clearly defensive, the functions of the other two sounds are unknown. We were unable to determine if P. argus is even responsive to its own sounds. Nor is the mechanism of sound generation known. One that would seem to be required on the basis of mechanical considerations does not appear to conform to the operation of the structure generally believed to be the sound-production mechanism of P. argus.