title: Functional ecology of the ciliate Glaucomides bromelicola, and comparison with the sympatric species Bromeliothrix metopoides.
abstract: We investigated the ecology and life strategy of Glaucomides bromelicola (family Bromeliophryidae), a very common ciliate in the reservoirs (tanks) of bromeliads, assessing its response to food quality and quantity and pH. Further, we conducted competition experiments with the frequently coexisting species Bromeliothrix metopoides (family Colpodidae). In contrast to B. metopoides and many other colpodean ciliates, G. bromelicola does not form resting cysts, which jeopardizes this ciliate when its small aquatic habitats dry out. Both species form bactivorous microstomes and flagellate-feeding macrostomes. However, only G. bromelicola has a low feeding threshold and is able to adapt to different protist food. The higher affinity to the local bacterial and flagellate food renders it the superior competitor relative to B. metopoides. Continuous encystment and excystment of the latter may enable stable coexistence of both species in their natural habitat. Both are tolerant to a wide range of pH (4-9). These ciliates appear to be limited to tank bromeliads because they either lack resting cysts and vectors for long distance dispersal (G. bromelicola) and/or have highly specific food requirements (primarily B. metopoides).
authors.affiliation: Research Institute for Limnology, University of Innsbruck, Herzog Odilostrasse 101, Mondsee, 5310, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Weisse
authors.forename: Ulrike
authors.initials: U
authors.lastname: Scheffel
authors.forename: Peter
authors.initials: P
authors.lastname: Stadler
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Foissner
mesh_terms: D031231:Bromelia / Q000469:parasitology*; D004463:Ecology; D005247:Feeding Behavior; D006863:Hydrogen-Ion Concentration; D061350:Sympatry; D016806:Tetrahymenina / Q000254:growth & development / Q000502:physiology*; D014867:Water / Q000737:chemistry; D014871:Water Microbiology
chemical_list: D014867:Water
keywords: Competition; Polytomella sp; feeding threshold; growth rate; life strategy; macrostome formation; neotropics; pH response