浑善达克沙地三趾跳鼠的食性与繁殖特征的初步分析

采用夹捕取样法对内蒙古浑善达克沙地三趾跳鼠(Dipus sagitta)种群进行逐月调查,根据捕获样本的繁殖器官特征及胃内容物组成分析三趾跳鼠的食性与繁殖的季节动态。结果表明,本地区三趾跳鼠主要取食植物茎叶,4、5、6、9、10月植物茎叶占其食物组成的95%以上,7～8月达60%～75%;三趾跳鼠还取食少量的植物种子;7～8月,嫩绿的植物种子占35%,但很少取食成熟种子。此外,也捕食少量昆虫。在浑善达克沙地,三趾跳鼠每年只繁殖1胎,繁殖期为5～7月,5月下旬至6月中旬为交配期,6下旬至7月中旬为幼鼠出生期。三趾跳鼠的胎仔数稳定,每胎产仔2～3只,平均胎仔数为2·8。6月份成体雌鼠的妊娠率为43%;7月份雌鼠的妊娠率为48%;其他月份妊娠率为0%。雄鼠睾丸下降时间为5～8月,6月雄性成体睾丸下降率达到最高峰,为100%。

Primary Study on the Diet and Reproductive Characteristics of Dipus sagitta in Hunshandake Sandy Land

The monthly killing-trap was applied on the population of the Northern Three-toed Jerboa(Dipus sagitta) in Hunshandake Sandy Land in Inner Mongolia from 2000 to 2006.Monthly food components of the jerboa were analyzed by the food component in stomach of each individual.The results indicated that the leaves and the stems of grass are the main food of the jerboa,which contribute more than 95 percent of the food in April,May,June,September and October.Besides the leaves and stems of grass,jerboas also take a few insects and seeds as food.In July and August,the consumption of the immature plant seeds of the jerboas may reach 35%.However,the jerboas seldom eat matured seeds.In Hunshandake Sandy Land,female jerboas can breed only once in the year.The reproductive period of the jerboas is from May to July.The litter size of the jerboa is ranged from 2 to 3 with a mean about 2.8.Based on current analysis,the pregnant rate of females is 43% in June,48% in July and zero in other months.Males with scrotal testis can be detected form May to August,and the peak value of matured males occurred in June.