Manipulative motor activity of the cuttlefish Sepia Officinalis during prey-capture

Following capture by the cuttlefish Sepia officinalis , crabs are manipulated by active movements of all eight arms to facilitate prey paralysis and ingestion. This manipulative behaviour is described for the first time. Prior to ingestion the prey is regularly held in a specific orientation, termed the "reference position", irrespective of the initial angle of attack. Prey capture is followed by an initial, very rapid manipulative phase, bringing the cephalo-thorax-abdomen junction of the crab to lie adjacent to the mouth of the cuttlefish. In this position the cuttlefish can inflict a wound, usually to the proximal joints of the hind pereiopod. The salivary toxins are probably injected into this wound provoking a rapid paralysis of the prey. A second manipulative phase orientates the crab into the "reference position". This phase involves complex coordinated movements of the arms that can, in some cases, rotate the crab by up to 180°. Suppression of visual input has little effect on this behaviour. Tactile input concerning the position and movements of the pereiopods would appear to play an important rôle in the execution of this manipulation. Sensorial control of this behaviour and the possible existence of muscular receptors capable of detecting movements are discussed.