Observations on the morphology and life cycle of Hymenolepis hopkinsi Schiller 1951 (Cestoda: Cyclophyllidea), a parasite of black ducks (Anas rubripes Brewster).

Abstract

Twenty-six of 65 black ducks (Anas rubripes) collected in New Brunswick from August 15, 1967, to December 15, 1969, have been found to harbor the cestode Hymenolepis hopkinsi Schiller, 1951. This cestode occurs in the caeca with the number of worms per bird ranging from 2 to 774 during the present study. Infections of 100–200 worms are common. The life cycle has been elucidated and egg strings, fed to Hyalella azteca, developed into viable cysticercoids. The resulting cysticercoids, when fed to a domestic duck, developed into adult cestodes. The life cycle is described along with a brief description of the adult. The characteristic egg strings and the cysticercoid are also described.