FEEDING-BEHAVIOR OF PARACENTROTUS-LIVIDUS IN THE PRESENCE OF CAULERPA-TAXIFOLIA INTRODUCED IN THE MEDITERRANEAN-SEA

Experiments in aquaria have shown that the feeding behaviour of the se a urchin Paracentrotus lividus in presence of the green alga Caulerpa taxifolia varies during the year. In summer, the alga is strongly avoi ded and is not consumed. in winter and spring, although the alga is on ly moderately appreciated, its consumption is significant, but it is h ardly or not at all absorbed. These results are confirmed by content a nalysis of the digestive tract of P. lividus sampled in situ in an are a colonized by C. taxifolia. The sea urchins' feeding behaviour is lin ked to the presence of toxic and repellent secondary metabolites of C. taxifolia, caulerpenyne in particular.