臭鼩的繁殖和种群年龄结构

对浙江萧山瓜沥区农田臭鼩的研究，发现种群性比不等，存在明显的两性异型。分析了雄体的性成熟率和雌体的怀孕率及性活动率的变化规律。一年中存在两个繁殖高峰期。以齿长指数为指标．臭鼩种群可划分为4个年龄组。探讨了种群年龄结构的季节变化及其自然寿命。

STUDIES 0N REPR0DUCTI0N AND P0PULAT10N AGE STRUCTURE OF SUNCUS MURINUS

A survey of the reproduction and population age structure of the musk shrew(Suncus murinus) was conducted in Guali farmland area of Xiaoshan County．Zhejiang Province．In the population of the musk shrew，the Sex ratio (males／females) was 1：0.72．The shrews showed a sexual dimorphism with the male being larger． The mean body weights of males and females were 54.9±1.13g and 37.9±0.70g and the mean body lengths of males and females were 122.9± 1.1Omm and 110.3±0.96mm respectively．The annual mean rate of Sex maturily of males was 86.3%. 5O% of males reached sex maturity when their tests weighed 0.1lg or their bodies 40g．All the males reached Sex maturity at 0.13g testicle weight or 50g body weight． The pregnant females were found nearly all the year round．35.7% of the females caught were pregnant and 49.6％ were sexually active．The average litter size was 3.5±0.16 ind．Among the pregnant shrews，25% were lactating.the females had two repro ductive peaks in a year，occurring in Mar．-Apr．and July- Aug．respectively．
Specimens of the musk shrews were divided into four a groupsby means of tooth 1ength index which was based upon tooth wear．The seasonal changes in the population age structure are also discussed．