Abstract: Objective To investigate the current status of overwintering mosquito breeding sites in Guangzhou and analyze their influencing factors, so as to provid a scientific basis for mosquito control during the overwintering period. Methods During January and February in 2025, stagnant water from various outdoor containers in Guangzhou was collected. Concurrently, environmental factors such as the sampling site type, container type, water quality, and meteorological conditions (temperature and humidity) were recorded.The collected water samples were then transported to laboratory for mosquito incubation and species identification.The hatching rates of mosquitoes were compared across different environment types, container types, water types, and water quality conditions. Logistic regression analysis was employed to assess the influencing factors on the positivity rate of mosquito hatching. Results A total of 979 water samples were collected, with a hatching positive rate of 4.49% for Aedes albopictus and 3.88% for Culex. Univariate analysis revealed that the Aedes albopictus hatch positive rates showed statistically significant differences across different regions, environmental types, container types, water quality conditions, and the presence or absence of adult mosquitoes resting around the water containers during sampling (P<0.05). Similarly, the Culex hatch positive rates showed statistically significant differences across different environmental types, water quality conditions, and the presence or absence of adult mosquitoes resting around the water containers during sampling (P<0.05). There was no statistically significant difference in the positive hatching rates of Aedes albopictus and Culex mosquitoes at different temperatures and humidity levels (P>0.05). Binary logistic regression analysis showed that the hatching positive rate of Aedes albopictus in urban breeding sites was significantly lower than in suburban areas (RR=0.515). Containers with potted plants, aquatic plants or aquatic vegetation had a higher likelihood of Aedes albopictus breeding compared to idle containers (RR=2.682). The hatching positive rate was higher in turbid water than in clear water (RR=3.380). Samples collected from water containers with adult mosquitoes resting nearby had a higher Aedes albopictus positive rate than those without (RR=4.422). Compared to urban residential areas, rural villages (RR=3.420) and other environments (RR=3.010) exhibited significantly higher Culex hatching positive rates in breeding sites. Turbid water bodies showed a higher Culex hatching positive rate than clear water (RR=2.215). Water samples collected from containers with adult mosquitoes resting nearby had a higher Culex hatching positive rate than those without (RR=3.949). Conclusion It is essential to enhance the monitoring of overwintering mosquito breeding sites. Proactively remove potential mosquito breeding grounds, including potted plants and aquatic plants. These efforts will lay a solid foundation for effective mosquito control throughout the year.

Key words: Aedes albopictus, Culex, Overwintering, Breeding sites, Hatch positive rates