Avoidance behaviour of Asterias rubens to extracts of Mytilus edulis,solutions of bacteriological peptone,and selected amino acids

The effect of some homogenates, peptones and amino acids upon the positive rheotactic behaviour of Asterias rubens L. is studied. It was found that homogenates of Mytilus edulis, solutions of bacteriological peptone L 37, L-glutamic acid and a mixture of 10 common amino acids acted as repellents and altered the positive rheotactic behaviour of A. rubens. The experimental evidence suggests that the active compound(s) of the homogenates of M. edulis and of the solution of L 37 is a heat stable substance whose molecular weight is lower than ca. 30,000. It was found that A. rubens sensed L-glutamic acid in concentrations of the part per million range. Sinergistic interaction was found between L-glutamic acid and a mixture of one or more other 9 common amino acids. It is shown that the sensitivity of A. rubens to one of the repellents, bacteriological peptone L 37, changes during the year. Among other factors, seasonal changes in sea-water temperature could account for this.