Peritrichs are widely studied ciliates; however, their eukaryotic epibionts have not
yet been examined in detail. Our study investigates the colonisation patterns and
seasonal dynamics of peritrich ciliates and their epibionts in lotic environments
over 14 sampling periods. In the early stages of colonisation, settlement was likely
characterised by random establishment, consistent with the lottery model of Chesson
and Warner. In later stages, the autogenic, ecosystem‐engineering role of peritrich
species facilitated the settlement of additional organisms on the substrate. During
warmer months, the structurally complex surface of peritrichs hosted a greater abundance
of epibionts—particularly choanoflagellates. Colonisation of the peritrich stalks
by attached filter feeders and other functional groups increased the filtration‐capable
surface area, thereby enhancing biofilm function. Additionally, the presence of predatory
ciliates such as Trachelius ovum can alter biofilm structure by consuming colonial
peritrichs. These findings highlight the crucial role of peritrichs in biofilm dynamics
and their contribution to community complexity in lotic ecosystems.
