Fig. 5. Schematic representation of contraction kinetics and the four resulting phases of a contraction cycle in T. wilhelma. The contraction phase is shorter than the expansion phase, resulting in a higher absolute value for the maximum contraction rate than the absolute values of maximum expansion rates . The phase of maximum contraction (P_C) is shorter than phase of maximum expansion (P_E), see also Table 1. Variations in contraction cycle length are solely due to differences in P_E.