Abstract
Adult A. tonsa specimens collected in Escambia Bay, Florida in Sept 1977, were heavily infested with Epistylis . Investigation by SEM revealed that lesions were produced in the copepod exoskletons at the sites of attachment of the ciliate stalks. Bacterial colonization near the lesions suggests that the bacteria may utilize dissolved copepod body contents which are lost through the lesions. This may be a factor in the seasonal succession of copepod species in estuaries.