Physiology of feeding inTritoniaI. behavior and mechanics

Abstract

T. diomedia locates its sea whip prey at a distance by detection of food odor gradients using its rhinophores. It then turns in the direction of ambient water currents which are detected by other sensory structures. The rate of locomotion is increased in water currents of higher velocity, or when the odor of certain coelenterates is added to the water stream. When food is centered on the oral veil surfaces it uses its radula, odontophore and jaws to bite-off and ingest short sections. Feeding supersedes courtship-copulation and resting behaviors, and is itself dominated by escape-swimming in the behavioral hierarchy. Feeding involves a bite-strike of the radula and jaws, and then a separate ingestion sequence involving odontophore movements which pull more food through the mouth and thrust it into the esophagus. Study of the innervation and co-ordination of the musculature of the buccal mass as well as stimulation of selected neurons and nerve trunks indicate that feeding motor control is exerted from the buccal ganglia. Specific nerve trunks and nerve cells which control movements of the lips, jaws and odontophore are identified. An unexpected route of innervation of the jaws and oral tube via the cerebral ganglia is described.