Gill ciliate
Spirocona tripartita
Spirocona tripartita is a unicellular ciliate that lives epizoically exclusively on the gill appendages of freshwater amphipods of the genus Gammarus. It has a cup-shaped body with a characteristic, spirally wound peristome (mouth region). The species is a commensal that utilizes the water current within the host's gill chamber to whirl in food particles without directly harming the host.
Details
Identification
Cup-shaped body, spirally twisted anterior end (peristome), attached to the gill lamellae of gammarids.
Social behavior
Often found in groups (colonies) on the same gill appendage of the host.
Diet
Feeds on bacteria, detritus, and tiny organic particles filtered from the host's respiratory water.
Hunting strategy
Passive filter feeder; creates a water current towards the mouth region through ciliary movement.
Overwintering
Overwinters together with the host or in the form of resting stages (cysts).
Ecology
Ecological role
Ectocommensal; regulates bacterial populations in the micro-environment of the host's gills.
Natural predators
Smaller predatory protozoa or micro-invertebrates.
Competitor species
Other sessile ciliates such as Lagenophrys or Suctoria (e.g., Dendrocometes).
Ecosystem service
Contributes to the self-purification of water through bacteria consumption.
Threats
Water pollution, pesticide use, and loss of host populations (amphipods).
Scientific profile
Profile
Habitat
Freshwater; obligate epibiont (commensal) on the gills of amphipods, particularly the genus Gammarus (e.g., Gammarus pulex).
Reproduction
Asexual reproduction via exogenous budding, producing ciliated swarmers (tomites); sexual reproduction via conjugation.
Ecological role
Epibiontic commensal; uses the host as a substrate and benefits from the host's water current for feeding, usually without directly harming the host.