关键词: 三带喙库蚊, 季节分布, 首现日, 突增日, 气温, 风向, 锋面过境天气

Abstract: The relationship between the first appearance in spring and seasonal distribution of Culex tritaeniorhynchus and the meteorological conditions in Fengxian District, Shanghai was studied using field survey data collected with light traps (from 18:00 to 06:00) in pigsties every night since from March 1 to June 30 in 1982-1992 and 2001-2002. Results of correlation contrast analysis, statistical analysis and weather chart analysis revealed that the seasonal distribution of C. tritaeniorhynchus can be divided into three stages: the first appearance date,the seasonal increase period and the mixed occurrence period. The temperature conditions at the first appearance of C. Tritaeniorhynchus were as follows: on the day of the first appearance and the day before the first appearance of C. tritaeniorhynchus, the mean daily temperature was over 11℃ and the cumulative temperature was over 25。5℃; or over an arbitrary three day period from two days before the date of first appearance to the day after the first appearance, mean daily temperature was over 11℃ and the cumulative temperature was over 34.0℃. The density of C. Tritaeniorhynchus (Y₁) over 5 day periods during the seasonal increase period was significantly positively correlated with mean daily temperature （X₁）; the univariate regression equation is Y₁= -9.3534+0.7217X₁ After the mean daily temperature over five days exceeded 18℃ (the mean date was 3 May), the density of C. tritaeniorhynchus entered the mixed occurrence period. Overall, close correlation exists between the seasonal distribution of C. tritaeniorhynchus and the mean daily temperature, wind direction and change of S-system. Dates on which sudden increases in C. tritaeniorhynchus were recorded were related to the movement of weather fronts. The density of C. tritaeniorhynchus increased markedly when the mean daily temperature over five days >18℃; this was an important temperature index for the beginning of the peak period. Theresults also point to the possibility of a northward migration pattern of C. tritaeniorhynchus in spring and early summer.

Key words: Culex tritaeniorhynchus, seasonal distribution, first appearance date, sudden increase date, air temperature, wind direction, weather fronts