THE EFFECTS OF 2 MU-M HG-VANNUS (CILIATA, HYPOTRICHIDA)(+ ON THE ETHOGRAM OF EUPLOTES)

Strains of Euplotes vannus (a marine hypotrichous ciliate) were treate d with 2 mu M Hg++. The ethograms of treated and control populations d iffer due to several traits, which are qualitatively described and qua ntitatively measured: (a) the creeping of treated populations is more uniform and continuous than that of controls; (b) typical behavioural patterns of controls (the ''slow down'' and the bursts of ''Side Stepp ing Reaction'' - SSR) disappear completely in treated ciliates; (c) th e SSR of treated organisms has an average rotation angle of 163 degree s (controls: 84 degrees); (d) the velocity decreases significantly in treated cells (340 mu m/s vs 450 mu m/s). These results are discussed from the point of view of their survival significance.