Change Rule of Population Quantity and Reproduction Characteristics of Niviventer fulvescens in Cengong County

The population quantity and reproduction characteristics of N.fulvescens were statistically analyzed based on the monitoring date from May,1984 to December,2013 in Cengong County,Guizhou to study the change rule of N.fulvescens population quantity and reproduction.N.fulvescensis the common rat,accounting for 7.90% of total captured rats with 0.21% of average captured rate.The population quantity in upland cultivation area is significantly higher than in rice cultivation area.Two peaks of yearly population quantity are in May and August and their average captured rates are 0.36% and 0.40% respectively.The reproduction period is from March and October and average pregnant rate is 32.15%.Two reproduction peaks occurs during March-April and June-August and their pregnant rates are 57.14%~66.67% and 37.50%~38.46%separately.The average litter size,average testicle declining rate and average reproduction index is 5.23,57.63% and 0.73 respectively.There is obvious difference in population reproduction between two reproduction seasons.