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Competition for fertilization in multi-male group spawning can drive variation in male reproductive investment (i.e., testis mass and sperm size). Inter-population comparisons of variation in energetic availability and allocation along geographical gradients allow insights into the mechanisms shaping the reproductive investments of animals. Although inter-population differences in female reproductive investment (i.e., clutch size and egg size) have been studied extensively across a wide range of taxa, little information on variation in reproductive investment in males is available. Here, we studied altitudinal variation in testis mass and sperm length among three populations in the Jingdong tree frog (Hyla gongshanensis jingdongensis), a polyandrous species, in Yunnan Province in China. The results showed that individuals exhibited smaller testes at higher altitudes while testes mass was positively correlated with body size, body condition and age. Longer sperm length was observed in the middlealtitude population. Moreover, we found that sperm number was positively correlated with testes mass and sperm length. Our correlational findings suggest that environmental constraints at high altitude select for less investment in testes and offspring number. [ABSTRACT FROM AUTHOR]

The article discusses the study for the determination of age and body size of large-webbed bell toads, Bombina maxima from a subtropical, high-altitude population in southwestern China, with the use of skeletochronology, that found no difference in mean age between the sexes. The study also revealed two years to be the minimum age of sexual maturity for both sexes, and maximum longevity to be six years for males and five years for females.

The article discusses the study which determined the ages of 249 odorous frogs, Odorrana grahami, from four locations in Sichuan Province, China, with the use of skeletochronology. It found from excised toe bone for 242 individuals, distinct lines of arrested growth (LAGs), with each LAG assumed to represent one year of age. The study also revealed significant differences in average adult snout-vent length (SVL) and age among female populations, but not in males.

Bergmann's rule states that, within species of endotherms, individuals tend to be larger in cooler environments, and has been reputed to apply to some ectotherms including amphibians. However, the validity of the rule has been debated, questioning whether Bergmann's dines are generally present in anurans. In the view, we studied altitudinal variation in body size in the rice frog (Rana limnocharis) among populations from Sichuan province located at three altitudes to find if there exist any differences in a relatively small altitudinal range (290-375 m). The results showed that individuals from higher altitudes tended to be larger in body size than lower altitudes, which was consistent with Bergmann's dine. Moreover, when the effect of age was removed, variation in body size of the frogs across altitudes still remained. Our findings suggested that age affected the pattern of variation in body size across the altitudinal dine, we also discussed that factors other than age also contributed to size differences among populations. [ABSTRACT FROM AUTHOR]

I used skeletochronology to estimate age structure of the Siberian Wood Frog, Rana amurensis, from northeastern China. Average age did not differ significantly between males and females. Age at sexual maturity in both males and females was 1 year. For both sexes the maximum age observed was 4 years. Average body size differed significantly between the sexes, with males being larger than females. A significantly and positively correlation between body size and age was found within each sex in the population. When the effect of age was controlled, males also had larger size than females, suggesting that sexual selection for larger males might improve male mating success. [ABSTRACT FROM AUTHOR]

In anuran mate choice, advantaged males are generally known to be larger or older individuals. To test whether male mating success in the foam-nesting treefrog Rhacophorus omeimontis, a species distributed in western China, correlated with body size and age, we analysed differences in body size and age among three types of males. Males were classified as mated, joining or unmated at the time of sampling with joining males being additional males joining pairs in amplexus. Our results showed that there were no significant differences in body size among the three types of males. However, age was an important factor, with mated males being significantly older than joining and unmated males, which indicated that older individuals tended to have greater mating success than younger frogs. [ABSTRACT FROM AUTHOR]

Age determination in amphibians is crucial to investigation of life-history traits. In this context, we studied age structure of the Guenther's frog, Hylarana guentheri, population from southwestern China located at an altitude of 300 m using skeletochronological method. Our results showed that age in adult males ranged from 1 to 4 years, and from 2 to 6 years in adult females. Average age in females was significantly older than males in 2008 and 2009. Also, females had significantly larger average body size than males in both years. A significant relationship between age and body size within each sex was found in this species for both years. The ANCOVA analysis revealed that there was significant difference in body size between sexes when the effect of age was removed. The von Bertalanffy's model showed that females had larger [ABSTRACT FROM AUTHOR]