Large molecules and chemical control of feeding behavior in the starfish Asterias forbesi

Abstract

1. An echinoderm, the starfish Asterias forbesi, is described as possessing a chemically mediated behavioral response which is suitable for use as a bioassay in studies on chemoreception. 2. Using A. forbesi for bioassays, it was discovered that protein extracts from the clam Mercenaria mercenaria and the oyster Crassostrea virginica chemically induced the humping reflex in this animal. 3. In every case, the protein extracts from clam were more active (lower ED50) than any from oyster. The highest molecular weight-range fraction from clam (100 000 and up) was the most active and had an ED50 of 0.34×10-6 mg protein/ml seawater in the test solution. 4. In laboratory and field tests, the higher molecular weight fractions obtained from ultrafiltration techniques exhibited a pronounced activity as a search-inducing stimulant. The starfish were induced to search at speeds of up to 8 cm/min. © 1973 Biologischen Anstalt Helgoland.