Infestation with the epibiotic ciliate (Zoothamnium spp.) may increase mortality rate and reduce body size of A. tonsa and, likewise,concluded the peritrichous ciliate Epistylis sp. to shorten the lifespan of A. bifilosa females. Similarly,the epibiotic euglenid Colacium vesiculosum has been associated with reduced egg production in A. tonsa females. In addition, epibionts are thought to negatively affect feeding, swimming, and respiration of copepods.