Objective To study the seasonal distribution of mosquito density and explore the relationship between mosquito density and meteorological factors in some areas of Qinghai Province, China.Methods The data on mosquito density of five surveillance points of Qinghai Province from 2018 to 2021 were analyzed using the circular distribution method to calculate the peak day and peak period of mosquito density at each surveillance point. A multiple linear regression analysis was conducted to determine the relationship between mosquito density and meteorological factors in Xining, Golmud, and Yushu of Qinghai Province with SPSS 22.0.Results The peak day of seasonal fluctuations of mosquitoes of surveyed points in Qinghai Province was July 19, and the peak period was from June 10 to August 28. The regression equation for mosquito density and meteorological factors was y=-2.19+0.47x₁+0.01x₃+0.02x₄ (x₁, mean air temperature; x₃, monthly average relative humidity; x₄, monthly mean air pressure) (F=20.613, P<0.001). Mosquitoes have been found breeding in Yushu City with an altitude of 3 700 meters.Conclusions There is a certain correlation between the mosquito density in some areas of Qinghai Province and the local monthly average temperature, monthly average humidity, and monthly average air pressure, and the peak period of mosquito density is basically concentrated in mid July.

Objective To investigate the species composition and spatial distribution of mosquitoes in the human habitats of the Yellow River basin in Qinghai province, China.Methods Ten counties/cities/districts in the Yellow River basin in Qinghai province were set as the study space. From July to September of 2018 to 2021, blood-sucking mosquitoes active at night were collected using mosquito trap lamps (Gongfu Xiaoshuai) around rural livestock pens and residential houses, followed by identification and classification. Excel 2016 was used to establish the database to calculate population dominance and niche breadth. SPSS 22.0 was used to perform hierarchical cluster analysis on the correlation coefficients between mosquito species.Results A total of 2 684 mosquitoes belonging to 12 species of 4 genera were captured,among which Aedes vexans was the dominant species with species abundance of 30.030. The species abundance of Aedes vexans, Ae. falvidorsalis, Culex pipiens pallens, and Cx. modestus is more than 10.000; The ecological breadth of Ae. detrituss, Ae. dorsalis, Ae. vexans, and Cx. pipiens pallens is more than 6; Geographic niche width of Ae. dorsalis, Cx. modestus, Anopheles sinensis, and Ae. flavescens is greater than or equal to 1.000. There were niche overlaps among 90% of mosquito species, with 13 pairs >0.50 (including one pair with a complete overlap). Ae. sergievi was found in Guide county for the first time.Conclusions Ae. vexans, Ae. dorsalis, and Cx. pipiens pallens have relatively high numbers of species, species abundance, ecological amplitude, niche breadth, and niche overlap in human habitats in the Yellow River basin of Qinghai province. These mosquito species are widely distributed and highly competitive in the plateau. It is the first time to discover Ae. sergievi, a new record in Qinghai province, China.