CHANGES IN METABOLISM AND BEHAVIOR OF THE FRESH-WATER COPEPOD CYCLOPSSTRENUUS ABYSSORUM INFECTED WITH DIPHYLLOBOTHRIUM SPP

In a population of copepods (Cyclops strenuus abyssorum), with a natur ally high prevalence of infection with procercoids of Diphyllobothrium spp., no difference in body size was found between infected and uninf ected hosts. However, a significant reduction in the reproductive capa city of infected females was observed, 87 % of uninfected females havi ng developed eggs in their gonads and sacs compared with 21 % of infec ted females. The feeding rate of infected copepods was relatively high soon after infection occurred, but gradually decreased to less than h alf that of uninfected animals. Respiration rate was also lower in inf ected copepods. Infected copepods showed reduced motility and impaired escape responses, which is likely to make them more susceptible to pr edation.