Detection of Dissolved Substances by the American Lobster (Homarus americanus) and Olfactory Attraction between Lobsters

Of 17 amino acids and other organic compounds tested at high concentration, 13 elicited feeding and walking responses in lobsters significantly greater than those elicited by seawater controls, but only 7 of 29 were stimulatory at low concentrations (alanine, beta alanine, glutamic acid, proline, succinic and malic acids, and tyrosine). Fourteen of 15 mixtures of 2–9 amino acids were stimulatory. There may have been potentiation in mixtures with cysteine HCl, lysine, glycine HCl, and methionine and antagonism in some with alanine and arginine. Freshly prepared seawater extracts of cod, shrimp, and lobster muscle were more stimulatory than any of the compounds or mixtures.Male lobsters responded more frequently to water from a tank with a recently moulted mature female lobster than to water from a tank with a nonmoulted mature female or a moulted or a nonmoulted male. It is possible that moulted females release a sex attractant (pheromone).