The predation of a luminescence-marked strain of Pseudomonas fluorescens by the soil ciliate Colpoda steinii was studied in soil microcosms. Bacterial cells were introduced in either small (neck diameter, <6 (mu)m) or intermediate-sized (neck diameter, 6 to 30 (mu)m) pores in the soil by inoculation at appropriate matric potentials, and ciliates were introduced into large pores (neck diameter, ...

IN a previous paper [Cutler and Crump, 1923] an account of experiments on mass cultures of Colpidium colpoda was given; the present communication deals with similar experiments carried out on cultures containing one or more cells isolated into one cubic centimetre or less of culture solution. The objects of these experiments have been to discover whether the results obtained from cultures conta...

Decades of experiments have demonstrated the ecological effect of competition, but experimental evidence for competitive effects on trait evolution is rare. I measured the evolution of six protozoan traits in response to competitors from the inquiline community of pitcher plants. Replicate populations of Colpoda, a ciliated protozoan, were allowed to evolve in response to intra- and interspecif...