Culex pipiens pallens Coquillet is an important public health pest and can spread various mosquito-borne infectious diseases. To assess the cold resistance of Cx. pipiens pallens, the supercooling points (SCPs) and freezing points (FPs) of Cx. pipiens pallens, including 1st through 4th larval instars, pupae, and male and female adults, were identified in the laboratory. SCPs of Cx. pipiens pallens ranged from −18.0353 to −7.9854°C. SCPs differed significantly among larvae, pupae, and adults (F = 338.434, df = 170, P < 0.05), but did not differ significantly between male (−17.9173 °C) and female (−18.0353 °C) adults. The mean SCPs of the imaginal stage were much lower than those of larvae and pupae. Unlike SCPs, the FPs of Cx. pipiens pallens, ranging from −12.8777°C to −5.5550°C, were not significantly different from 1st instars through the pupal stage, but were much higher than those of the imaginal stage (F = 29.92, df = 170, P < 0.05). These results suggest that Cx. pipiens pallens has the potential to spread farther northward into higher-latitude regions in China.
Culex pipiens pallens