Termination and reinduction of reproductive diapause by photo‐period and temperature in males of the grasshopper, Oedipoda miniata

. Previous publications have demonstrated that O.miniata adults exhibit an aestival reproductive diapause during the dry summer in Israel; females do not lay and males show only little mating behaviour. It was also reported previously that photoperiod and temperatures corresponding to autumn in Jerusalem terminate diapause and induce intense male mating behaviour, whereas continuous illumination and high temperatures maintain diapause. In the present study we used mating behaviour as an indicator for investigating the effects of several photoperiod—temperature combinations on reproductive diapause in O.miniata males. Mating behaviour was induced and diapause terminated under the following conditions: LD 10.5:13.5, T = 38‐27°C (the temperatures during the photophase and scotophase, respectively); LD 12:12, T=38–27°C; LD 12:12, T=26–13°C; LD 14:10, T = 26–13°C. In contrast, diapause was maintained under LD 14:10, T = 38–27°C and under LL with high but variable temperatures. In further experiments males that were already sexually active, and which had been kept under LD 12:12, T = 38–27°C, were transferred to LL with high variable temperatures. Similarly, postdiapause males which had been kept under LD 14:10 and T=26–13°C were transferred to T = 38–27°C without changing the photoperiod. In both instances mating behaviour declined, then disappeared, thus reinduction of the diapause occurred under such conditions which previously were found to maintain diapause. O.miniata is therefore a ‘short day’ and/or ‘low temperature’ insect. This is the first report on complete control of photoperiod—temperature over aestival reproductive diapause and its reversibility in a male insect.