北京大兴地区黑线仓鼠种群繁殖生态研究

黑线仓鼠(Cricetulus barabensis)是我国华北地区广泛分布的农田主要害鼠之一。1982年9月到1985年3月,作者在北京、天津及河北省一些地区,调查了它的分布和群落结构并研究其种群生态,本文仅就北京郊区大兴县黑线仓鼠的种群繁殖问题进行讨论。

STUDIES ON THE POPULATION REPRODUCTION ECOLOGY OF STRIPED HAMSTERS IN DAXING COUNTY,BEIJING

This paper deals with the breeding characteristics of striped hamsters in Daxing, Beijing, from September, 1982 to March, 1985. Among the 1003 specimens collected, 472 are males and 531 are females. The reprodution status are as follows:1. The sex ratio of all the specimens proves that the female accounts for a larger proportion than the male, and such is the case in the young and subadult groups, but males are more than females in the adult and old groups.2. Emphasis of the studies is laid on the correlationship between the testis weight and the body weigiht. The testis weight of adults is 0.7g and over, the testis weight of subadults is 0.15-0.69 g, the testis weight of youngs is O.lg and below. The male is involved in the reproductive activities throughout the year except a short period (from mid-Nov. to next early Jan.).3. The beginning of the breeding period varies with years. In 1983 and 1985 it began in Feb. and in 1984 it started in March. Young striped hamsters became matured within 2 ?3 months. Females also stop breeding from Nov. to next Jan. and they have two breeding peaks in a year. The first peak was between Spring and Summer and the second was between Autumn and Winter. Adult striped hamsters breed 2-3 times each year. In 1983 the annual average litter size of female adult was 5.844±0.212 and 6.821 ± 0.898 in 1984.4. The ecological life-span of a female striped hamster involved in reproductive activities is about one year.The reproductive indices are calculated by the following formulas I = NE/P, I representing the reproductive index; P the total number of captures; N the number of pregnancies; E the average number of litter size. They showed also reasonal and annual changes.