Widespread epibiontic relationship is best known as a commensal relationship, but several studies have shown also harmful influences on hosts by epibionts. A laboratory experiment was carried out to investigate the effect of peritrich ciliates (Epistylis sp.) as epibionts on the survival of Acartia bifilosa (Copepoda). Copepods were collected from the Gulf of Riga and the trial was made in seawater taken from the same location as the zooplankton samples. Adult copepods were divided into four groups by sex and by infection with epibionts. Results of the trial suggest that animals infested with epibionts were less viable than the uninfested ones. This pattern was significant in the case of females, but not males. Comparison of performance by sexes showed that the survival rate was significantly higher among females than males. The results further suggest that epibiontic protozoans may also influence egg production of copepods, because of shorter life span of females, and therefore may play a substantial role in copepod production and community dynamics.
Fernandez-Leborans, G. 2004. Protozoan epibionts on Mysis relicta Loven, 1862 (Crustacea, Mysidacea) from Lake Lüšiai (Lithuania). Acta Zool. (Stockh.), 85, 101–112.
Fernandez-Leborans, G. & Tato-Porto, M. L. 2000. A review of the species of protozoan epibionts on crustaceans. I. Peritrich ciliates. Crustaceana, 73, 643–683.
Gilbert, J. J. & Schröder, T. 2003. The ciliate epibiont Epistylis pygmaeum: selection for zooplankton hosts, reproduction and effect on two rotifers. Freshwater Biol., 48, 878–893.
Green, J. D. & Shiel, R. J. 2000. Mobiline peritrich riders on Australian calanoid copepods. Hydrobiologia, 437, 203–212.
Hirche, H. J. 1974. Die Copepoden Eurytemora affinis Poppe und Acartia tonsa Dana und ihre Besiedlung durch Myoschiston centropagidarum PRECHT (Peritricha) in der Shiel. Kiel. Meeresf., 30, 43–64.
Ho, J. & Perkins, P. S. 1985. Symbionts of marine copepoda: an overview. Bull. Mar. Sci., 37, 586–598.
Kankaala, P. & Eloranta, P. 1987. Epizoic ciliates (Vorticella sp.) compete for food with their host Daphnia longispina in a small polyhumic lake. Oecologia, 73, 203–206.
Kotta, J., Simm, M., Kotta, I., Kanošina, I., Kallaste, K. & Raid, T. 2004. Factors controlling long-term changes of eutrophicated ecosystem of Pärnu Bay, Gulf of Riga. Hydrobiologia, 514, 259–268.
Line, R. & Sidrevics, L. 1995. Zooplankton of the Gulf of Riga. In Ecosystem of the Gulf of Riga between 1920 and 1990 (Ojaveer, E., ed.), pp. 175–186. Estonian Academy Publishers, Tallinn.
Manca, M., Beltrami, M. & Sonvico, D. 1996. On the appearance of epibionts on the crustacean zooplankton of a large subalpine lake undergoing oligotrophication (L. Maggiore, Italy). Mem. Ist. Ital. Idrobiol., 54, 161–171.
Simm, M. & Ojaveer, E. 2000. Dynamics of copepods and fish larvae in Pärnu Bay (NE part of
the Gulf of Riga) in the spring–summer period. Proc. Estonian Acad. Sci. Biol. Ecol., 49, 317–326.
Threlkeld, S. T. & Willey, R. L. 1993. Colonization, interaction, and organization of cladoceran epibiont communities. Limnol. Oceanogr., 38, 584–591.
Utz, L. R. P. & Coats, D. W. 2005. Spatial and temporal patterns in the occurrence of peritrich ciliates as epibionts on calanoid copepods in the Chesapeake Bay, USA. J. Eukaryot. Microbiol., 52, 236–244.
Weissman, P., Lonsdale, D. J. & Yen, J. 1993. The effect of peritrich ciliates on the production of Acartia hudsonica in Long Island Sound. Limnol. Oceanogr., 38, 613–622.
Wiktor, K. & Krajewska-Sołtys, A. 1994. Occurrence of epizoic and parasitic protozoans on Calanoida in the Southern Baltic. Bull. Sea Fish. Inst., 132, 13–25.
Willey, R. L., Cantrell, P. A. & Threlkeld, S. T. 1990. Epibiotic euglenoid flagellates increase the susceptility of some zooplankton to fish predation. Limnol. Oceanogr., 35, 952–959.
Xu, Z. & Burns, C. W. 1991. Effects of the epizoic ciliate Epistylis daphinae, on growth, reproduction and mortality of Boeckella triarticulata(Thompson) (Copepoda: Calanoida). Hydrobiologia, 209, 183–189.