啮齿动物胎仔数和纬度关系的研究

作者根据53年92篇文献中关于啮齿动物胎仔数研究资料，利用秩相关对我国10个啮齿动物物种(大仓鼠Cricetulus triton，黑线仓鼠Cricetulus barabensis，东方田鼠Microtus fortis黑线姬鼠Apodemus agrarius，褐家鼠Rattus norvegicus，黄毛鼠Rattus losea，黄胸鼠Rattus flavipectus，小家鼠Mus musculus，子午沙鼠Meriones meridianus和高原鼢鼠Myospalax baileyi胎仔数和纬度的相关关系进行了研究．在10个啮齿动物物种中，小家鼠(居民区)、黑线仓鼠和黄胸鼠的胎仔数与纬度呈正相关，其它物种的胎仔数和纬度不相关．胎仔数具有种的特异性，它的大小受一系列因素(如种群年龄结构、种群密度、母体体重、婚配制度、生境、年份、食物等)的影响，现有资料尚不支持啮齿动物胎仔数随纬度上升而增加的一般性结论．

A Study of Relationship Between Litter Sizes of Rodents and Latitudes

Rank correlation analysis were utilized to characterize relationship between latitude and the litter sizes of ten species of rodents,including Greater long-tailed hamster(Cricetulus triton),Striped hamster (Cricetulus barabensis),Reed vole(Microtus fortis),Striped field mouse (Apodemus agrarius),Brown rat (Rattus norvegicus),Lesser ricefield rat(Rattus losea),Yellow-checked rat(Rattus flavipectus),House mouse(Mus musculus),Midday gerbil(Meriones meridianus) and Plateau zoker(Myospalax baileyi). At 95% significance level,of 11 rank correlation coefficients,3 for M. musculus,C. barabensis and R. flavipectus are significant,the other 6 positive ones and 2 negative ones are not significant different from zero. The results do not suggest that rodents produce larger litters at higher latitudes than they do at lower latitudes. The litter sizes are different for various species of rodents. Every population has its own optimal litter size. But the optimal litter size does not necessarily increase with latitude. It is influenced by a series of factors,such as population age structure,population density,habitat characteristics,diet contents,maternal weight and mating systems.