COLONIZATION, INTERACTION, AND ORGANIZATION OF CLADOCERAN EPIBIONT COMMUNITIES

The distribution of three genera of epibionts on two Daphnia species was examined in two subalpine beaver ponds. Epibiont prevalence and burden were proportional to body length in both species of Daphnia, but varied between the two Daphnia species and among female Daphnia with parthenogenic eggs in different stages of development. The most common epibiont appeared to have a doubling rate of 1 d-1, but this rapid growth rate was insufficient to increase epibiont burdens on Daphnia in a pond where salamanders fed selectively on Daphnia serving as epibiont substrates. There were two indications of significant interactions between epibiont taxa: inverse relationships between prevalence of each epibiont species and the burden of the most common epibiont, and nonrandom distributions of epibiont species combinations among the substrate organisms. There was no effect of two epibiont genera (Carchesium, Chlorangiella) on Daphnia egg production, but the negative effect of the third, most locally abundant, epibiont genus (Colacium) was proportional to its abundance.