Changes in pedal intramuscular pressure corresponding to behavior and locomotion in the marine gastropods Busycon contrarium and Haliotis kamtschatkana

Abstract

Pedal intramuscular pressure recordings from the marine gastropods Busycon contrarium and Haliotis kamtschatkana were made using a wick catheter. Patterns of pressure fluctuations corresponded to a range of behavioral modes and locomotor speeds and reflected the morphological differences between the two regions of the foot, the columellar muscle and tarsos. Recordings from stationary specimens of both species showed sinusoidal pressure fluctuations corresponding to the heart beat. Pressure fluctuations in the foot of crawling Busycon were irregular and corresponded to the muscle action of its indistinct locomotor wave. Those from crawling Haliotis were characterized by regularly spaced, larger pressure peaks ascribable to the localized increase in pressure caused by the passing locomotor wave. The frequency and amplitude of these peaks increased with the speed at which Haliotis crawled. Additional large pressure pulses of over 3.4 kPa were recorded when snails twisted or lifted their shells, or brought their shells closer to the substratum, movements that are caused by the contraction of the columellar muscle.