The activities of digestive enzymes as a determinant factor in the localization of Tetrabothrius erostris (Loennberg) (Cestoda: Tetrabothriidae) in the intestine of the herring gull Larus argentatus Pontoppidan

We determined the parameters of invasion and localization of Tetrabothrius erostris (Loennberg) (Cestoda: Tetrabothriidae) in the intestine of herring gulls Larus argentatus Pontoppidan (adults and nestlings). Adult herring gulls have T. erostris parasites in the proximal and middle segment of their small intestine. Nestlings have T. erostris in the middle segment of their small intestine. High activities of the digestive enzymes (proteases and glycosidaeses) in these segments of the intestine were found. Apparently, this factor, as well as the physiological peculiarities of the development of T. erostris, determine the localization of tetrabothriids in the intestine of herring gulls.