关键词: 三带喙库蚊, 气象分析, 下沉气流, 春季, 迁飞

Abstract: Objective To approach to the meteorological conditions of the first emergence of Culex tritaeniorhynchus in Spring.Methods Whole night collection of mosquitoes(from 18∶00 o'clock to 6∶00 o'clock of the following day) with light traps was carried out in pigsties every night since March 1 st every year.The adult mosquitoes caught were anaesthetized,then identified and counted.The density of mosquitoes was calculated by the average number of mosquito per trap and one night.Comparative analysis of the meteorological data at the first emergence of Culex tritaeniorhynchus and Anopheles sinensis were made.Results The meteorological conditions of the first emergence of Culex tritaeniorhynchus in Spring were as follows:①In 2-3 days before the first emergence ofCulex tritaeniorhynchus there blew strong S-system wind on the ground level and at 850 HPA(1 500m),accompanying with sudden increasing of the wind speed(>5.0 m/s) of S-system direction on the ground and the increasing of the frequency( 94.9% and 82.4%) of SW direction at HPA,as well as the water vapour pressure increasing on the day of the first appearance and the day before.②There were fronts passing through Fengxian,Shanghai or shear of wind direction in the first appearance of Culex tritaeniorhynchus from 1 a.m.to 6 a.m.of the following day,and the frequancy of the precipitation from 8 p.m.to 6 a.m.of the following day was 69.2%(9/13).③The variations of atmospheric pressure in the 12 hours from 8 p.m.to 8 a.m.of the following day were all possitive value.Conclusion The meteorological conditions of Culex tritaeniorhynchus emerging in spring were not the same as that of the Anopheles sinensis which overwintered in local area but in conformity with the landing pattern of seasonal northward migratory insects,which were transported by the SW-air-current and the sinking airflow due to the passing through of the front with the rain-fall,or the shear of wind direction and the positive variations of atmospheric pressure.Therefore,it demonstrated another indirect evidence of northward migration of Culex tritaeniorhynchus.