The nudibranch Melibe leonine feeds using the rhythmic movements of its large oral hood to capture small crustaceans that are present in the water column. The frequency of these feeding movements, or hood closures, is proportional to the concentration of available prey. The purpose of this study was to determine what qualities of prey cause the rate of these feeding movements to change. Animals were observed during exposure to the following treatments: (1) filtered seawater; (2) Artemia-conditioned seawater (smell); (3) small particles in seawater; (4) particles soaked in Artemia-conditioned seawater; (5) frozen Artemia and; (6) live Artemia. Both conditioned water and particles caused appetitive behavior (orientation of the oral hood) and a significant increase in the frequency of hood closures. This incrase in rate had a rapid onset and was maintained throughout the duration of the 20-min test period. The major difference between the effects of the two stimuli was that smell alone led to incomplete feeding cycles while particle treatments yielded normal feeding behavior. When applied together these stimuli produced a larger response than either one did alone. However, no combination of stimuli was as effective as live prey. We conclude that both tactile and chemical cues are sufficient to elicit an increase in the feeding movements of Melibe leonine, but some additional stimulus provided by live prey, such as vibrations, may play an important role as well. The information provided by these stimuli helps initiate appetitive and early aspects of the consummartory phases of feeding, and also influences full expression of the rhythmic feeding motor program.
Jackson Estuarine Laboratory, Biological Sciences
Watson, W. H. III. and C. M. Chester. 1993. The influence of olfactory and tactile stimuli on the feeding behavior of Melibe leonina (Gould, 1852) (Opisthobranchia: Dendronotacea). The Veliger 36: 311-316.
© CMS, Inc., 1993