The ethograms of Tetrahymena pyriformis GL and T. malaccensis

The behaviour of Tetrahymena, one of the most intensively investigated laboratory organisms, was analysed, and ethograms of T. pyriformis and T. malaccensis were studied. The basic ethogram, which previously described the behaviour of ciliates was appropriate for T. pyriformis and T. malaccensis. Although quite similar to each other, the two new ethograms differed significantly in some aspects of ciliate behaviour. Four new behavioural patterns were recognized and described quantitatively and qualitatively, viz induced continuous trajectory change, induced continuous reorientation reaction, sliding and coiling. The complexity of these results is discussed per se and also from a comparative point of view.