中国林蛙种群形态特征及雌体生殖力的地理差异

Geographic variation of morphological characteristics and female fecundity in different populations of Rana chensinensis

为了比较中国林蛙(Rana chensinensis)不同种群的形态特征、两性异形和雌体生殖力等方面的地理变异,在中国林蛙分布范围的南部(河南郑州)和北部(内蒙古扎兰屯)采集标本共130只,测量了两性的体长、体重等26项形态特征和雌体的生殖力。结果表明:(1)中国林蛙的形态特征及两性异形方面存在显著的地理变异,雌性显著大于雄性,扎兰屯种群显著大于郑州种群;(2)中国林蛙形态特征的地理变异符合贝格曼定律,但四肢的形态变化规律不符合阿伦规律,体形较大的扎兰屯种群存在两性异形的形态特征数量少,但差异程度大,与伦施法则不符;(3)雌性是中国林蛙两性中形态特征地理变异最明显的一方,在对寒冷气候的适应过程中,雌性比雄性的体长和体重增加的程度更明显。由此可知,两性间身体大小变化趋势的不一致暗示不同性别的个体适应环境变化的策略可能存在较大差异,这是造成中国林蛙不同种群两性异形和雌体生殖力地理变异的主要原因。

A total of 130 specimens from two Rana chensinensis populations were collected in this study, with the Zhengzhou population （ Henan Province） being the southern part of the range and the Zhalantun population （Inner Mongolia） being the northern part of the range. Female fecundity and 26 morphological characters in males and females were measured to examine geographical variation of different populations. The results showed that females were significantly larger than males. The body size of Zhalantun population was significantly larger than that of Zhengzhou population, which is in accordance with Bergman＇ s rule. However, the length of the limbs was also larger in the cold climate that does not conform to Allen＇ s rule. Sexual size dimorphism in R. chensinensis did not obey Rensch＇ s rule. Females should be more sensitive to environmental changes because they could grow faster than males in snout-vent length and weight which ensures their greater reproductive success. The different variation trends in body sizes between females and males across different environment imply the substantial differences in their adaptation strategies, which should be the main reason for geographic variation in morphological characteristics and female fecundity across different populations.