三带喙库蚊幼虫稻田孳生状态及分布型研究

Study on the Spatial Distribution Patterns of Culex tritaeniorhynchus Giles Larvae in Paddys Fields

本文报告浙江石牛稻作区1988～1990年三带喙库蚊幼虫田间孳生状态及分布型研究结果。根据连续三年在晚稻分蘖后期,对9块稻田分层随机抽样所得数据,经分离散分布的理论拟合及聚集指标测定,认为符合负二项分布规律。其K值及C值均>O,m~*值均>1;Iwao模式中a值>0,B值>1,说明该蚊幼虫在田间分布的基本成份是个体群,形式呈聚集型分布。时序动态的测定结果表明,随着蚁幼龄期的增长,个体群之间的聚集度逐渐减弱。田问孳生状态调查结果表明,周边区平均密度(2.1821条/勺)明显高于中间区(1.6982条/勺);不同方位比较均以西、北方向密度最低。

Culex tritaeniornynchus is one of the species breeding in the paddy fields, and an important vector of Japanese B encephalitis in China. This paper dealt with the spatial distribution patterns of C. tritaeniorhynchus larvae in the rice fields. All study was undertaken in Lishui county, Zhejiang province from 1988～1990.Density of mosquito larvae was surveyed in 9 plots of rice fields, It was proved that the distribution of C. tritaeriorhynchus Iarvae in paddy fields was mostly in aggregated pattern and was goodness-of-fit for agreement with neagative binomial distribution. Both values of K and C are>0; application of Iwao's model of them* -m method to the analysis of spatial pattern, a>0, β>1. It indicates that C. tritaeniorhynchus larvae fit aggreation distribution in the form of colony in paddy fields.The coefficient of variation(C. V) between peripheral part and central part of rice field are 137. 79-248. 56% respectively. Comparison of the mean densities between these two parts (2.1821: 1.6982)u=3.01, p<0.01. This showed a significant difterence. The densities of larvae also showed different positions was remarkable difference, the mean density of larvae was lower in Northern positions