鄂尔多斯沙地草场小毛足鼠8年繁殖生态的研究

目的研究小毛足鼠繁殖生态。方法1991—1998年每年的4—10月中旬在鄂尔多斯沙地草场的不同生境内，利用直线夹日法调查，捕获鼠全部称重、测量后解剖，记录繁殖情况。结果1991—1998年在该地共捕鼠10种，小毛足鼠是优势种之一，占捕获鼠的30．93％。共捕获小毛足鼠2562只，其中雌性1258只，雌性比为（49．10±1．94）％，性比年度和季节变化不明显。雄鼠年平均睾丸下降率为（70．55±2．47）％，睾丸下降2月开始10月结束。雌性年平均怀孕率和胎盘斑率分别为（26．39±2．43）％和（21．38±2．27）％，平均胚仔数和胎盘斑数分别为（6．23±0．18）个和（5．38±0．49）个，年平均繁殖2次的占雌鼠的（4．13±1．10）％。平均繁殖指数为1．062±0．162，雌性繁殖3月开始11月结束。睾丸下降率、雌性怀孕率和繁殖指数的年际与季节变化明显。结论小毛足鼠性比、雄性睾丸下降率、雌性怀孕率及胎仔数等年度间和季节均有差异。

Study on breeding ecology of Phodopus roborovskii in Ordos sand-land grassland for 8 years

Objective Study the breeding ecology of desert hamster（Phodopus roborovskii）. Methods The population dynamics of P.roborovskii was investigated at different habitats in Ordos sand-land grassland in the middle ten days from April to October during 1991 to 1998 by rectilinear-trapping method. The trapped rodents were weighed, surveyed and dissected, and the breeding condition was recorded. Results Ten kinds of rodents were captured from 1991 to 1998. The desert hamster was one of dominant species, which accounted for 30.93% of all captured rodents. A total of 2562 desert hamsters were captured, including 1258 females with the proportion of （49.10±1.94）%. There was no significant difference in sex ratios with the change of seasons and years. The average decreasing rate of testicle in male was （70.55±2.47）%, and it began to decrease in February, ending in October. Average pregnant rate and placenta rate were （26.39±2.43）% and （21.38±2.27）%, respectively. The average number of fetal rats and placenta were （6.23±0.18） and （5.38±0.49）, respectively. The females that produced two times each year accounted for （4.13±1.10）%. Average reproduction index was 1.062±0.162. The reproduction period of females was from March to November. The decreasing rate of testicle in scrotum, pregnant rate and reproduction index had obvious changes with seasons and years. Conclusion There was significant difference among sex ratio, declining rate of testicle in scrotum, pregnant rate and fetal rats quantity of P.roborovskii with seasons and years.