Fig. 3. Water vapor exchange at different vapor activities in females of Culex pipiens. For each point, the vapor exchange was determined as in Fig. 1. ND25, mosquitoes reared under a nondiapausing photoperiod (15 h:9 h, L:D) at 25°C; ND18, mosquitoes reared under a nondiapausing photoperiod at 18°C; D18, mosquitoes reared under a diapausing photoperiod (9 h:15 h, L:D) at 18°C.