凹耳蛙的两性异形

The Sexual Dimorphism of Odorrana tormota

测量和比较采自黄山的凹耳蛙成体标本(雌雄各20个),统计结果表明成年雌雄蛙的体长、头宽、吻长、鼻间距、眼间距、眼径、鼓膜宽、前臂及指长、前臂宽等两性形态学指标存在显著性差异。对与体长显著相关的形态特征,以体长为协变量的协方差分析表明凹耳蛙雌雄两性在头宽、眼间距、眼径、鼓膜宽存在显著差异。凹耳蛙两性异形比达到0.418,雌性平均体长对雄性平均体长的比达到1.716。头宽、眼间距、眼径、鼓膜宽等局部形态特征与体长的线性回归分析表明,雌性斜率大于雄性斜率,说明雌性凹耳蛙上述局部特征随体长的生长速率明显大于雄性。雌性体长的繁殖力选择能够很好地解释凹耳蛙的两性异形。

Twenty male adults and twenty female adults of Odorrana tormota, collected from Mountain Huang, were com- pared and measured in this study. The results showed significant difference in snout-vent length （SVL）, head width, snout length, internasal distance, interorbital distance, eye diameter, tympanum diameter, length of lower arm and hand, width of lower arm. The results from the ANCOVA indicated that there were significant sexual dimorphism in head width, interorbital distance, eye diameter and tympanum diameter. The index of sexual dimorphism reach 0. 418 and female Odorrana tormota frogs are on average 71.6% longer in body length than that of the males. The linear regression equation between SVL and four characters showed that female adults have bigger growth rate with the growth of snout-vent length in head width, interorbital distance, eye diameter and tympanum diameter than that of the male adults. The theory of the fecundity selection on female body size could explain the sexual dimorphism of Odorrana tormota properly.