摘要
在洞庭湖区域,社鼠(Niviventer confucianus)种群主要栖息在山区和丘陵地带的林地内。总体而言,其种群雌性比基本维持在50%左右,但在季节间和年龄组间有一定的差别,雌性比在冬、春季较低,夏、秋季的雌性比都超过50%。年龄组间,雌性比最高的为幼年组66.7%,亚成年和成年组的雌性比接近50%,而老年组的雌性比为最低,为33.3%。所有雌鼠全年的怀孕率为31.1%,平均胎仔数为3.7只,繁殖指数为0.58。春、夏季怀孕率较高,冬季没有捕获到怀孕的雌鼠,仅捕获到有怀孕经历(有宫斑)的雌鼠。繁殖指数在夏、秋季维持高峰水平。雌性社鼠总的参产率为53.3%,各季间呈现从春、夏到秋逐渐增加的趋势,冬季停止怀孕。可见夏、秋季为雌鼠的繁殖高峰期。随着年龄组增长,平均胎仔数有明显增加的趋势,老年组胎仔数最高,而繁殖指数以成年组最高,说明成年组是种群中繁殖的主体。雄性社鼠的睾丸下位率全年总计为75.6%,分四季平均为86.0%,夏、秋季维持在较高水平,冬、春季稍低,低谷在春季。下位睾丸的重量与大小有明显的季节变化,呈现春、夏、秋、冬逐渐下降的规律,春季与冬季相比,有显著性差异,说明开春后,雄性社鼠在生殖潜能上已有明显变化。这些特征与雌鼠的繁殖高峰基本吻合。说明社鼠主要在春、夏、秋季繁殖,繁殖盛期在夏秋季。从不同年龄组看,幼年组个体不参与繁殖,亚成年组个体开始参与繁殖,繁殖主体是成年组个体。
Sulphur bellied rats （ Niviventer confucianus ） were collected from Taoyuan County in 1998 to 2001, from YueYan County in 1992 to 1994, and in 2003 to 2004. The animals were caught primarily in their preferred woodland habitat. A total of 109 specimens were captured, and 90 animals were autopsied to determine reproductive condition. Position, size and weight of testes were noted in males. For females, the reproductive tract was examined for tubal condition of the uterus, number and size of embryos, and placental scars. Specimens were assigned to four age classes based on body mass： juvenile （body weight ≤ 35.0g）, sub-aduh （body weight from 35.1-50.0g）, adult （body weight from 50.1-80.0g）, and old-adult （body weight 〉 80.0g）. Males with testes had dropped into the scrota, and females for which the uterus was tubal were considered sexually mature Females with embryos or visible uterine scars were considered as reproductive animals.
The total sex ratio （M/F） is approximately 1 ： 1, but it varies in different seasons and with different age class. The proportion of females is higher than that of males except during spring and winter, and is higher in juvenile （66.7 % ） and but lower in old- adults （33.3 % ）. The total percentage of pregnancy in captured females was 31.1%, which also varied with season and age classes. Rates of pregnancy in spring, summer and autumn were 38.1%, 37.5% and 30.0%, respectively, with no breeding in winter. Juveniles were immature with no reproductive activity, but the sub-adult group （20.0%） had begun to reproduce. Proportion of pregnanacy was highest for the adult group （40.0%）, and dropped （33.3%） in the old-adult group. The average number of embryos in a litter was 3.7 - 1.3 （Mean ±SD）, and ranged from 2 to 8. Litter size varied with changes in the seasons, being lowest in spring （3.0±0.8）, highest in autumn （5.0±1.0）, and intermediate in summer （4.3±1.5）. The litter size of the animals increased with age class �
出处
《生态学报》
CAS
CSCD
北大核心
2006年第3期884-894,共11页
Acta Ecologica Sinica
基金
国家十一五科技攻关项目(2005BA529A05)
中国科学院知识创新工程重要方向资助项目(KZCX2-SW-415)~~
关键词
社鼠
繁殖生态
洞庭湖区
sulphur bellied rat （ Niviventer confucianus）
reproductive ecology
Dongting lake region
