湛江市褐家鼠种群年龄划分及繁殖特征

The population age and reproductive characteristics of Rattus norvegicus in Zhanjiang city

目的了解湛江市褐家鼠种群年龄结构和繁殖力变化,为鼠害预警及制订科学的防控措施提供理论依据。方法于2008-2011年采用笼捕法捕获褐家鼠,测量体重、胴体重、体长及尾长等指标,解剖观察生殖器官发育及其繁殖状况;根据体重的频次分布特征并参照发育与繁殖状况制订年龄划分标准。结果按体重可将褐家鼠分为5组,即幼年组（Ⅰ,体重≤120g）、亚成年组（Ⅱ,体重120-180g）、成年Ⅰ组（Ⅲ,体重180-240g）、成年Ⅱ组（Ⅳ,体重240-390g）和老年组（Ⅴ,体重〉390g）。各年龄组间的体重与胴体重呈正相关,按体重及胴体重法划分的年龄组总体拟合度高,频数差率为4.54%。雌鼠妊娠率在前4个年龄组随年龄增长而增加,并在成年Ⅱ组达到高峰,平均胎仔数和繁殖指数也随年龄的增长而增加;雄鼠的睾丸随着年龄增长而增大,睾丸下降率由15.79%逐渐增加到100%。结论可采用体重法划分褐家鼠种群年龄;湛江市褐家鼠种群的繁殖力随年龄的增长而增强,种群繁殖主体为成年组和老年组。

Objective To clarify age structure and fecundity of Rattus norvegicus population in Zhanjiang city, providing theoretical basis for early warning and formulating scientifie prevention and control measures of rodent pests. Methods Rattus norvegicus were captured by cage traps from 2008 to 2011. Body weight, carcass weight, body length and tail length of test rats were measured. Reproductive organs were anatomized and developmental status was observed. Age groups were divided according to the frequency distribution characteristics of body weight and the developmental and reproductive status. Results Rattus norvegicus were divided into five age groups, juvenile group （ 1, ≤ 120 g）, subaduh group （ 11, 120-180 g）, adult group I （ III, 180-240 g）, adult group II （IV, 240-390 g）, and old group（ V, 〉390 g）. Body weight and carcass weight between neighboring age class had extremely significant positive correlation. The overall fitting degree of age class based on body weight and carcass weight was high and the frequency dissimilarity rate was only 4.54%. The pregnant rate of the females kept increasing in all age classes and reached peak at age class IV. The average fetus and reproductive index kept increasing in all age classes. The size of testes kept increasing with age and the descending rate increased from 15.79% to 100%. Conclusion It was feasible to identify age classes by body weight. The population fecundity of R. norvegicus in Zhanjiang city kept growing in all age classes. The breeding population was mainly the adults and the old individuals.