贵州地区黑线姬鼠种群繁殖特征

黑线姬鼠(Apodemus agrarius)是贵州地区分布广泛的主要农田害鼠之一,掌握其种群繁殖特征可为种群动态的预测预报提供基础资料。1984~2014年间,采用夹夜法逐月调查了贵州省余庆县8个县(市)监测点黑线姬鼠种群动态数据,分析了其种群性比、雌鼠怀孕率和平均胎仔数、雄鼠睾丸下降率等主要繁殖生物学指标及其地理差异和季节性变动规律,明确了贵州地区黑线姬鼠种群的繁殖特征。共捕获黑线姬鼠20 113只,不同地区种群间,除平均胎仔数有显著差异外(χ~2=36.503,df=7,P0.01),其他繁殖特征值均没有差异。从时间序列看,种群中雌鼠怀孕率和雄鼠睾丸下降率的季节性变化均表现为春季(4~5月)及夏末秋初(8~9月)达到高峰的双峰型。雌鼠产仔数一般2~10只,4~7只最为常见(占93.87%)。不同季节平均胎仔数差异不大。贵州地区黑线姬鼠繁殖的总体特点为全年繁殖,春秋两季为繁殖的高峰期,冬季(12月份和翌年1、2月份)繁殖强度明显低于其他季节(F_(11,84)=61.92,P0.01),但种群密度表现为6月达到最高点的单峰型特点。

Reproduction Characteristics of the Striped Field Mouse (Apodemus agrarius) Population in Guizhou Province

Striped Field Mouse (Apodemus agrarius) distributes in Guizhou Province broadly, which is one of the key pest rodents in farmland. To better understand reproduction characteristics of the Striped Field Mouse population in Guizhou Province, we monitored the mouse populations in Yuqing, Xifeng, Cengong, Kaili, Leishan, Duyun, Wengan, Dafang counties from 1984 to 2014 (Table 1), assessed the reproduction parameters including sex ratio, pregnant rate of females, average fetuses and percent of males with prominent testicle, and analyzed the pattern of monthly variation of Striped Field Mouse in Guizhou. We totally trapped 20 113 mouse and made observation. There were no differences in the reproduction index between geographical populations except for average fetuses (Table 2). A two-peak type of breeding season was revealed by the monthly variation of female pregnant rate and percent of males with prominent testicle (Fig. 4). The highest proportion of pregant females occurred in spring (from April to May) and in the end of summer to beginning of autumn (from August to September) (Fig. 3). The litter sizes varied from 2 to 10, with common size of 4 to 7 (Fig. 5). The average litter size varied monthly (Fig. 6). Generally, pregnant females were present at two peaks, one in spring and one in autumn. The proportion of pregant femaled was lowest in winter (from December to February of next year). The population abundance reached the peak in June (Fig. 1).