Sexual Dimorphism and Feeding Habits of Rana pleuraden

563 specimens of Rana pleuraden collected from May 1998 to October 2003 were anatomized (♀235, ♂223) for feeding habits analysis, and 73 adult frogs whose body length was larger than 40 mm were measured (♀41, ♂32) for sexual dimorphism study.It was showed by the result that R.pleuraden principally feeded on animal food and there was no significant difference in feeding habits between the male and the female frogs.It was derived that the feeding habits did not lead to sexual dimorphism polarization.The results of t-test indicated that the body length of the female adults of R.pleuraden was obviously larger than that of the male adults, indicating that Rana pleuraden belonged to female larger body type.The variance analysis showed that there were significant differences in the tympanum diameter and in the hand length between the male and the female R.pleuraden.Sexual dimorphism was primarily determined by the ultimate factor of sexual selection.The larger body size of the female frogs could enhance the ability of reproductive exports as well as increase its ability of loading the males.There are sound nuptial pads with dense cutin tubercles on the base of the first finger of the male adult frogs, which may increase the embracing friction, strengthen embracing ability to avoid female frogs from escaping.The male frogs of R.pleuraden have a vocal sac to sound loudly, which is helpful to attract the female frogs in courtship competition.