Fig. 1. Net water loss rates in females of Culex pipiens reared under diapausing (D18) and nondiapausing conditions (ND25; ND18) at 0.00 a_v. The slope of the regression through the points represents the water loss in % h^-1. M_t is the mass at any time t and M₀ is the initial water mass. Values are means ± s.e.m. of 60 mosquitoes. 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.