上海地区三带喙库蚊春季首次出现、季节分布及其与气象条件的关系

根据1982～1992年和2001～2002年上海奉贤地区每年3月～6月灯诱捕蚊的现场调查数据,采取相关对比分析、统计分析、天气图分析法,探讨三带喙库蚊春季首次出现、季节分布及其与气象条件的关系。结果表明,三带喙库蚊季节分布按蚊虫密度变化划分为首次出现期、季节增多期和混合发生期三个时期。三带喙库蚊春季首次出现的温度条件是：首现日当天和前1天的日平均气温均≥11.0℃,其2天的日平均气温累加值≥25.5℃,或首现日当天、前2天和后1天任意连续3天的日平均气温均≥11.0℃,其3天的日平均气温累加值≥34.0℃,结果三带喙库蚊春季首现日和首现日温度日期的差异在1～2天内(91.7%)。三带喙库蚊季节增多期其逐候蚊虫密度（Y₁）与平均气温（X₁）呈显著的正相关,用一元回归方程表示为：Y₁=-9.3534+0.7217X₁;至候平均气温≥18℃（平均始日为5月3日）进入三带喙库蚊混合发生期。总体上三带喙库蚊蚊虫密度季节分布与平均气温、“S”系风向变化存在密切关系。首次出现期至季节增多期三带喙库蚊突增日与锋面天气活动存在着较大的关联,候平均气温≥18℃是三带喙库蚊大量发生和进入峰期重要的温度指标。上述结果提示上海地区三带喙库蚊春季和初夏随气流北迁降落的可能性相当大。

The relationship between the first appearance in spring and seasonal distribution of Culex tritaeniorhynchus and the meteorological conditions in Shanghai

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.