Open AccessSize‐selective feeding by Cyclidium sp. on bacterioplankton and various sizes of cultured bacteria
Author(s) -
Šimek Karel,
Vrba Jaroslav,
Hartman Petr
Publication year - 1994
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.1994.tb00102.x
Subject(s) - bacterioplankton , ciliate , biology , bacteria , bacterivore , protozoa , predation , microbiology and biotechnology , pseudomonas , ecology , nutrient , phytoplankton , genetics
Size‐selective grazing by Cyclidium sp., isolated as a dominant ciliate bacterivore from the Římov Reservoir (South Bohemia), was examined using fluorescent labelled bacteria (FLB) produced from natural bacterioplankton or pure bacterial cultures. Sizes of ingested bacteria in food vacuoles were measured directly. Three experimental arrangements were used: (1) Ciliates were grown on the pure culture of Alcaligenes xylosoxidans and fed with various proportions of ‘large’ and ‘small’ FLB (mean biovolume, 0.377 and 0.202 μm 3 , respectively) prepared from the same bacterial species. Results clearly showed significant selection of larger bacteria. (2) Ciliates were grown on natural bacterioplankton from the reservoir and subsequently fed on FLB prepared from the reservoir bacterioplankton (mean biovolume, 0.065 μm 3 ). Independent of either prey or predator abundance, larger FLB (> 0.100 μ m 3 , and especially those > 0.200 μ m 3 ) were ingested with much higher frequency than their occurrence i the natural assemblage. (3) Ciliates were grown on the reservoir baterioplankton and fed by FLB prepared from the culture of Pseudomonas sp. In contrast with previous results, no size selection of the ciliate was found when FLB were different from the bacterial food used to grow the ciliate. Ecological impacts of size‐selective bacterivory are suggested.