Abstract: This paper deals with the population fluctuation characteristics and relations to environmental factors in Mus caroli，an important rodent pest of crops．Trapping was
monthly conducted in cultivated land in Tonghai County，Yunnan Province from January of 1990 to Septembet of 1993．A tatol of 15 811 trap-days．captured 1 027 rodents，in which Mus caroli accounted for 76.14% ．
Significant differences of average of monthly popultation numbers between different years were found．The population fluctuation usually peaked twice a year，i．e．during May to June and in November．The density fluctuation seems to be related to developmental stages of crops and also reproductive activities of animals．
The population numbers in May related closely tothe average of monthly mean temperature during February to March and to the population numbers in January．Two linear and one multiple linear regressions were run of estimated the population numbers in May of the year.

Key words: Mus caroli, Population fluctuation, Environmental factors

摘要： 本文报道卡氏小鼠(Mus caroli)种群数量变动特征及其与环境等因子的关系。种群数量年间变动较大，季节变化一般出现2个高峰，分别在5-6月和11月，与农作物的成熟、收获以及小鼠繁殖活动有关。1月份的种群数量多寡及2、3月份的月平均气温高低，对当年5月份种群数量有密切关系。本文提出了3个回归方程式，可初步估计当年5月的种群数量。

关键词: 卡氏小鼠, 种群变动, 环境因子