PARTICLE CAPTURE BY FAVELLA SP (CILIATA, TINTINNINA)

Particle capture by the tintimnid ciliate, Favella sp., was investigated with high-speed video microscopy. Experiments with microspheres and algal cells indicate that within the size range 1-19 mu m, behavioral responses are partly responsible for the differential capture of large over small particles. For example, 4 mu m microspheres or Isochrysis [equivalent spherical diameter (ESD) similar to 4.5 mu m] are only captured if they are encountered in the inner zones of the encounter area. Ten micrometer microspheres or Heterocapsa (14-19 mu m ESD) are captured with a greater efficiency than smaller particles from the inner zones, but can also be captured from the outer zone of the encounter area. Capture of particles from the outer zone is associated with ciliary reversal. Microspheres and algal cells of similar size are captured in a similar manner.