4 -6 times left often
||Young KD. The selective value of bacterial shape. Microbiol Mol Biol Rev. 2006 Sep70(3):660-703 DOI: 10.1128/MMBR.00001-06 p.685 left column 2nd paragraphPubMed ID16959965
|| Matz, C., J. Boenigk, H. Arndt, and K. Jurgens. 2002. Role of bacterial phenotypic traits in selective feeding of the heterotrophic nanoflagellate Spumella sp. Aquat. Microb. Ecol. 27: 137-148 doi:10.3354/ame027137  Matz C, Kjelleberg S. Off the hook - how bacteria survive protozoan grazing. Trends Microbiol. 2005 Jul13(7):302-7 DOI: 10.1016/j.tim.2005.05.009  Pernthaler J. Predation on prokaryotes in the water column and its ecological implications. Nat Rev Microbiol. 2005 Jul3(7):537-46 DOI: 10.1038/nrmicro1180PubMed ID15935676, 15953930
||Primary source  abstract: "The influence of different bacterial phenotypic traits on the feeding selectivity of a bacterivorous nanoflagellate was investigated in laboratory experiments. Twelve bacterial isolates from freshwater habitats were characterized in terms of cell size, morphology, capsule formation, surface hydrophobicity and charge, and swimming behavior. Mechanisms of differential flagellate feeding on these isolates were studied in short-term grazing experiments by high-resolution video microscopy using the nanoflagellate Spumella sp. as a model interception-feeding predator."
||P.685 left column 2nd paragraph: "Hydrodynamic calculations indicate that bacteria smaller than 0.5 μm in diameter encounter grazing protists four to six times less often than do larger cells (∼1 μm), and filamentous cells or cells with diameters greater than 3 μm are often too large for protists to ingest (primary sources). Therefore, cells in the intermediate size range are consumed more rapidly, very often creating a “bimodal effect” that selects for the very large or the very small (Fig. 8) (primary source 246)."