FEEDING AND DIGESTION IN THE TROPICAL SEA URCHIN DIADEMA ANTILLARUM PHILIPPI

Abstract

Diadema antillarum Philippi feeds principally upon algae. Feeding activity is greatest during the afternoon and early evening and food passes through the gut in 8–12 hours. Because of the considerable amount of calcium carbonate ingested with its food, the species is of importance as an erosive agent on reefs. Enzymes for the digestion of carbohydrates with α glucoside and β glucoside linkages are present in the gut. Secretion of carbohydrases takes place in the caecum. Proteases are secreted by the caecum and foregut. A weak lipase is present. The histology of the digestive tract is described.