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Epizoans on a tropical freshwater crustacean assemblage

Abstract:

Prevalence and substrate specificity of epizoans on crustacean zooplankton were examined during an annual cycle in Tule Reservoir, a large, shallow and polymictic waterbody in western Venezuela. Epistylis sp, a ciliate protozoan, and Synedra sp., a pennate diatom, were the most frequent epibiont taxa. The prevalence of all epibionts on 1800 individual crustaceans was only 3.3%, and the occurrence of the two epibiotic taxa together on the same substrate zooplankter was low (3.3% of total infested crustaceans). Cyclopoid copepods were preferred as substrate for Epistylis sp. Neither epibiont taxon was found on copepodids or adults of a calanoid. Both epibionts were absent in the early rainy season but appeared in mid rainy season and showed the highest prevalence in the early dry season. During the remainder of the dry season prevalence was low. Epibiont prevalence was not related to presence or absence of zooplankton taxa or water temperature. Differences from temperate epibiont communities are discussed.