The infection of Moina macrocopa by a colonial peritrich, Epistylis daphniae, and its effects on the host

• 1 The effects of infection by Epistylis daphniae on its host, Moina macrocopa, were studied in the laboratory at 28°C by comparing the growth, reproduction and survival between infected and uninfected hosts.
• 2 Infestation by epizoites had little or no effect on the survival of the dadoceran hosts when adequate food was present.
• 3 The infected cladocerans had lower growth rates as juveniles, lower net reproduction rates as adults, and smaller body size at death than uninfected hosts.
• 4 The index of infection at different stages in the life cycle was related to the durations of intermoult period. Ranked in order of both index of infection and intermoult duration, the development stages were: old adult > young adult > juvenile.