Reproduction in Australian elapid snakes I. Testicular cycles and mating seasons

Testicular cycles and mating seasons of eight species of elapid snakes are described. Four livebearing species (Austrelaps superbus, Hemiaspis signata, Notechis scutatus and Unechis gouldii) show spermiogenesis in summer, retain active spermatozoa in the vas deferens all year, and mate in both autumn and spring. Hemiaspis daemelii shows a similar testicular cycle, but its mating season is unknown. Another livebearing species, Pseudechis porphyriacus, shows spermiogenesis in spring, retains spermatozoa in the vas deferens only during spring, and mates only in spring. Two oviparous species (Pseudonaja nuchalis and P. textilis) show spermiogenesis in spring (and possibly also in summer), and retain spermatozoa in the vas deferens all year. Both Pseudonaja species mate in spring, and possibly through summer. These data are consistent with the hypothesis that the times of production of spermatozoa, and retention of spermatozoa in the vas deferens, are adapted to the timing of the mating season.