Fig. 7. Contraction properties of longitudinal muscle 169 (from non-oviposition segments) from females less than 5 days old and females more than 18 days old. (A,B) The length/tension curves revealed no age-dependent differences. Muscle fibres were not able to tolerate extensions of more than 4–4.5 mm (arrows indicate breakage of muscle fibres). Only the passive tension (B) was slightly increased in muscles of females more than 18 days old. fl/fmax, muscle tension at a particular length normalized to maximum tension. (C) The maximum tension exerted by muscle 169 of females more than 18 days old was consistently higher than that of females less than 5 days old, although the difference was not significant (P>0.05; Mann–Whitney rank sum test). TW, twitch. Values are means + S.E.M. (D) No consistent difference was found with respect to contraction kinetics (see also Table 1).
