Fig. 4. Sinusoidal stimulation of the femoral chordotonal organ (fCO) (amplitude 100 µm); movement response. (A) Middle legs. (Ai) Relationship between stimulus frequency and response amplitude (tibia movement). Solid line, mean values (± S.D.) from seven male middle legs (n=41–162 per data point) (optical recording method). Dotted line, mean values from a strongly responding female (attached-flag method). In both cases, values from the first 10 cycles were used. The shaded lines are the curves for Carausius morosus (upper curve, data for the first stimulus cycle) (Kittmann, 1991) and Cuniculina impigra (lower curve, habituated situation) (Bässler and Foth, 1982). Horizontal broken lines indicate a gain of 1 (see text). (Aii) The phase shift between the stimulus and the response plotted versus stimulus frequency; data from the same animals as in Ai. Values are plotted separately for the relationship maximum joint flexion minus maximum fCO release (open circles) and maximum joint extension minus maximum fCO elongation (filled circles). The shaded line shows the corresponding curve for Carausius morosus, as above. (Bi,ii) Corresponding graphs for hind legs (seven males; one female).
