Preliminary evaluation of underwater sound detection by the cephalopod statocyst using a forced oscillation model

Abstract

To understand the mechanism of the peripheral auditory system of the cephalopod statocyst, the frequency dependence of particle motion sensitivity in cephalopods was estimated using a physical model of the sensory system, which was assumed to be forced oscillation. Reported perception thresholds of Sepia officinalis, Octopus vulgaris, and O. ocellatus fit the model well at low frequencies, whereas at frequencies above 150 Hz, the empirically measured threshold increased more steeply than the predicted increment. These results indicate that the frequency response of the perception threshold of cephalopods to particle motion can be primarily understood using the forced oscillation model, while unknown factor(s) play a role in the higher frequency range. Cephalopods are thought to be sensitive to low-frequency particle motion rather than high-frequency motion. The evolutionary function of cephalopod acoustical perception is not clear; however, the data suggest that they recognize the low-frequency particle motion that may be generated by prey, predators, and conspecifics.