Growth and Synchrony of Reproductive Organs in Males and Females of Rana pleuraden   in Kunming Area, Yunnan

Fourteen to sixteen specimens of Rana pleuraden (the numbers of male and female almost equal) were collected and dissected each month. Their snout-vent length, weight of body fat, spermary and ovary, volume of spermary, and diameter of oviducts were measured. The lengths of the snout-vents were analyzed by an ANOVA as a covariate factor. The results showed that there were significant differences in the weight of spermary and ovary, volume of spermary, and diameter of oviduct, which changed annually. The breeding season of R. pleuraden appeared from April to June and the breeding peak appeared from late May to early June. The analysis of allometric and regression showed that the growth of reproductive organs was mostly positive allometric (b>1) with snout-vent length or body weight. This meant that the growth of reproductive organs was substantially influenced by individual growth. The bigger individuals spawned at least twice per year, which was one of the reproductive strategies to enhance successful reproduction. The development of reproductive organs was negative allometric (b<1) to the weight of body fat. Body fat provided energy for reproduction and hibernation. Weight of body fat declined to the lowest point during the breeding peak. When less fat was deposited, a few individuals would delay hibernation in order to accumulate more energy to ensure safe living through the winter. The analysis of a Pearson correlation and cross correlation showed a significant correlation in the development of reproductive organs both in males and females. However, development of reproductive organs in males and females were not completely synchronic, and the spermary grew slowly because the maturation of eggs required longer time compared to sperm. Volume of spermary developed synchronously with diameter of oviduct, which was a good preparation for insemination.