Stability and modulation of Aplysia feeding behaviour: A parametric study.

The ingestion of Ulva strips 10 cm long, 1 or 2 cm wide (narrow and wide ribbon) was automatically recorded and analysed in Aplysia depilans. Graphs expressing ribbon displacements as a function of time were obtained. They showed a sequence of alternate slow and fast movements (slow and fast “phase"). The duration of a slow phase was positively correlated with the fast phase following it, but not with the one preceding it. The elementary cycle was characterized in standard conditions by three parameters: 1) length ingested (L); 2) time duration (D); 3) ratio between fast phase duration and whole cycle duration (F). The parameters remained stable during a sequence. Compared with narrow ribbon ingestion, wide ribbon ingestion led to a rise in D and a fall in L, and resulted in a reduction of the feeding efficiency. D rose in partially fed animals. With a narrow ribbon, the application of loads exerting a traction opposing ingestion did not induce significant variations in L, D, or F; with a wide ribbon, L and F fell as load increased. [ABSTRACT FROM PUBLISHER]