PREDATION BEHAVIOR OF LAND PLANARIANS

Predatory behaviour of land planarians is seldom observed or reported. Aspects reported are (1) finding prey; (2) attack behaviour; (3) capt ure using adhesive mucus, pharyngeal action, poisonous secretions, phy sical embrace; (4) feeding by extension of pharynx, releasing copious digestive fluid. The species Bipalium kewense, B. adventitium and B. p ennsylvanicum attack earthworms, immobilizing them by physical holding , digesting by pharyngeal secretions and then ingesting the treated ti ssue. Group attacks on giant African land snails involving chemotactic tracking, occur in Platydemus manokwari and Endeavouria septemlineata . Specialized capture methods are used by some species; Rhynchodemus s ylvaricus uses an expanded cephalic hood to capture small insects and in Africa, termites are captured by the elongated anterior of Micropla na termitophaga as planarians wait within the colony air shaft opening s to ensnare the workers in sticky mucus. The result of extensive pred ation by land planarians may seriously reduce the prey, e.g., providin g effective population control of giant land snails by introduced Plat ydemus manokwari, or causing serious depletion of desirable earthworm populations by the exotic Artioposthia triangulata in North Ireland.