HOST PREFERENCE, SEASONALITY, AND COMMUNITY INTERACTIONS OF ZOOPLANKTON EPIBIONTS

We examined host preference, seasonality, and zooplankton-epibiont community interactions of three phototrophic epibionts: Colacium calvum, Colacium vesiculosum, and Synedra cyclopum on pelagic crustacean zooplankton over a 4-yr period in Oneida Lake, New York. The three epibionts were most common from midspring to early summer. Colacium calvum and S. cyclopum preferred Daphnia as a host over all other taxa and C vesiculosum preferred cyclopoids followed by Daphnia. The prevalence of all three epibionts was directly correlated to the density of Daphnia, and no zooplankton were observed with these epibionts when Daphnia was absent from the zooplankton community. Predation on Daphnia by age-0 fish indirectly limited the seasonal presence of both Colacium spp. Synedra cyclopum was abundant in years when water transparency and Daphnia pulex abundance were highest, and rare in years when transparency was low and Daphnia galeata was the most abundant Daphnia. Lake nutrient concentrations had no discernible effect on epibiont abundance.