应用胴体重指标鉴定贵州省褐家鼠的年龄

为完善贵州省农区主要害鼠种群年龄鉴定划分标准体系建设内容。对2002~2009年贵州省余庆、息烽、三都、关岭、大方5个县捕获的441只褐家鼠(雌鼠201只,雄鼠240只)胴体重统计分析表明,褐家鼠平均胴体重为(69.16±30.45)g,雌、雄鼠之间胴体重差异不显著。根据胴体重的频次分配特征,参照繁殖状况,本研究将褐家鼠划分为5个年龄组,并制定了各年龄组胴体重划分标准:幼年组(Ⅰ)(≤40.0 g),亚成年组(Ⅱ)(40.1~80.0 g),成年Ⅰ组(Ⅲ)(80.1~120.0 g),成年Ⅱ组(Ⅳ)(120.1~160.0 g),老年组(Ⅴ)(160.0 g以上)。研究表明,不同年龄组胴体重、体重、体长、尾长、后足长、耳长之间具有极显著差异,随着种群年龄的增长而不断增加;胴体重与体重、体长、尾长、后足长、耳长之间具有极显著的正相关关系;不同年龄组种群繁殖力存在显著差异,随着种群年龄的增长,种群繁殖力不断增加;参与种群繁殖的主要群体为成年Ⅰ组、成年Ⅱ组和老年组,平均怀孕率为51.39%,平均睾丸下降率为93.51%,平均繁殖指数为2.583 9。种群年龄组成具有明显的季节变化特征。

Application of Body Weight without Viscera Indicators for Age Identification of Rattus norvegicus in Guizhou

In order to improve the population age identification and classification criteria system of the main agricultural rodent in Guizhou Province, we analyzed the weight of 441 samples of Rattus norvegicus （201 female, 240 male） which were captured in Yuqing, Xifeng, Sandu, Guanling and Dafang County in Guizhou Provience from 2002 to 2009. The average body weight without viscera was （69. 16±30. 45 ） g, and no significant variation was observed in weight between sexes. According to the frequency distribution of weight, the R. norvegicus were divided into five age groups. The weight division standard for each age group was determined as Juvenile （ ≤40.0 g）, Sub-adult （40. 1 -80.0 g）, Adult Ⅰ（80. 1 - 120.0 g）, Adult Ⅱ（ 120. 1-160. 0 g）, and Old-adult（ 〉 160. 0 g）. Between different age groups, there was significant variation in body weight without viscera, body weight, body length, tail length, hind length and ear length. With the growth of population age, these indicators increased continuously. Highly significant positive correlations was investigated between body weight without viscera and body weight, body length, tail length, hind length or ear length. Also, significant variation in population reproductive capacity was obtained from different age groups. Population reproductive capacity of R. norvegicus would increased continuously with growth within age categories. AduhⅠ, adult Ⅱand old-adult were the main reproductive contributors. Additionally, the average pregnancy rate, average rate of scrotal testis and reproductive index of testicle were 51.39%, 93.51% and 2. 583 9, respectively. There is significant seasonal variation in the population age structure.