Biochemical investigation of two responses involved in the feeding behaviour of Acanthaster planci (L.). II. Isolation and characterization of chemical stimuli

Feeding behaviour is induced in the crown-of-thorns starfish, Acanthaster planet (L.), by two kinds of chemical stimulus originating in coral. One is macromolecular, and the other of low molecular weight, largely accounted for by small peptides and amino acids.It is found that, under experimental conditions, starfish rapidly habituate to a chemical stimulus which at first strongly induces feeding behaviour.The pronounced withdrawal response which occurs when a crude extract of coral is applied to the starfish (a response apparently identical with that evoked by contact with live coral) is caused by a component which corresponds closely in chromatographie behaviour with proline. Proline itself produces the response, but is present at too low a concentration in coral to account for the observed activity.