The Quantitative Analysis of the Hydra-Hydramoeba Host-Parasite System
Several species of the freshwater hydras have been reported infected with the protozoan amoeba parasite Hydramoeba hydroxena Entz. Entz (1912) and Reynolds and Looper (1928) found the greatest level of infection in late summer through December. The latter author suggested the hydramoeba posed a “serious threat” to the hydra population. Epidemic levels of the infection have also been reported by Welch and Loomis (1924) and Miller (1936) in Douglas Lake, Michigan, and by Bryden (1952) in his work on Hydra oligactis in Tennessee. All reported highest levels of the parasite in the autumn, considerable deterioration of the hydra populations by the amoeba, and even complete disappearance of one hydra species due to the infection (Bryden, 1952). Further field studies of this host-parasite system are generally lacking.
KeywordsInfection Rate Host Population Infected Host Initial Infection Host Density
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