Planktivore effects on zooplankton epibiont communities: Epibiont pigmentation effects

Abstract

We observed the development of epibiont communities on freshwater crustacean zooplankton from 12 July–31 August 1991 in three ponds: one with planktivorous fish, a second with planktivorous larval salamanders, and a third with planktivorous fish added midway through the sampling period. Prevalence, on zooplankton, of pigmented euglenoid epibionts (Colacium vesiculosum), alone and with unpigmented peritrich ciliates (Vorticella campanula and Epistylis sp.), was significantly reduced by the addition of planktivorous fish in the third pond, while the prevalence of peritrich ciliates alone was not. Neither of the ponds with unaltered planktivore regimes showed a similar pattern of change in prevalence of pigmented and unpigmented epibionts on zooplankton. The relative loss of pigmented euglenoid epibionts, after planktivore addition, suggests that epibiont color or contrast may increase the susceptibility of their substrate organisms to planktivores.