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Sexual size dimorphism (SSD) is a widespread phenomenon commonly attributed to sex-specific patterns of selection on body size. Using data from Dengchigou population of the Omei treefrog (Rhacophorus omeimontis) in Fengtongzhai National Nature Reserve, southwestern China, we evaluated the hypothesis that direct phenotypic selection on both males and females can produce SSD. Female biased-SSD was generally driven by selection on females due to fecundity advantage of large body size rather than sexual selection favouring large male body size. Furthermore, differences in life-history traits (i.e. growth rate and/or time available for growth) between the sexes also resulted in female biased-SSD. Our findings suggest that the relationship between female size and fecundity supports the prediction that selection for fecundity drives female biased-SSD. [ABSTRACT FROM AUTHOR]

Producing sperm is energetically inexpensive, and strong competition for mating partners can lead to increased size of the testes in an effort to enhance reproductive success. On the other hand, selection on testes size can also be imposed by environmental conditions. We studied altitudinal variation and directional asymmetry in testis weight in a high-altitude frog (Rana kukunoris) endemic to the Tibetan plateau (2300-3500 m altitude). Testis weight decreased with increasing altitude and body size. The left testis was significantly larger than the right testis for all populations, and relative asymmetry between testes was unrelated to altitude or body size. The harsh environmental conditions at high altitudes may constrain the ability of males to allocate energy towards increased testis size. They could also be associated with altered operational sex ratios, thus reducing the strength of male-male competition. [ABSTRACT FROM AUTHOR]

The article discusses a study which described age and growth of Feirana taihangnicus, a stream-living frog endemic to central China, examined by skeletochronology. It compares the size, reproductive age, and lifespan of the male and female frogs. It also discusses the metamorphosis of tadpoles and the low population turnover rates of the species which highlight a conservation concern for the species.

The article presents research on the mating patterns of distinct populations of the species Bufo raddei at three elevations in southwestern China. It discusses findings that showed random mating among amplectant pairs of the species with respect to body size as measured by snout-vent length. It explains four conditions in the natural mating behaviour among the species including short pre-spawning period, strong male-biased operational sex ratio, and male densities or male advertisement calls masked by background noise.

The article discusses a study which examined the age structure, clutch size and body size of Rana kunyuensis, a subtropical frog endemic to China. Frog specimens were collected from Mt. Kunyu in Shandong. The age of maturity of female and male frogs was found to be two years and one year, respectively. Males have a maximum age of four years while females have a maximum age of five years. A positive correlation was found between body size and age. There was also a positive correlation between clutch size and body size.

The article discusses a study on mate recognition in male temperate frog Rana kukunoris, which is endemic to China. The study investigated the ability of male R. kukunoris to make a distinction between conspecifics of different sexes, between equal-sized gravid and non-gravid females and between gravid females of various sizes. The study found that large females were preferred by males than smaller ones. According to the authors, the findings suggest that male R. kukunoris rely on the release calls of males to distinguish between sexes and on visual cues to discriminate between females of various sizes.

The article discusses a study on the breeding ecology of the stream-dwelling frog Feirana taihangnicus conducted in the Taihangshan National Nature Reserve in Heilonggou in north Henan province of China. The study's findings on sexual dimorphism, population composition, oviposition habitat, breeding season, larvae development and population size are detailed. According to the authors, the frog species appear to trade offspring size against offspring number. The need to conserve the species is tackled as short-term declines in size of the breeding population were observed.

The article discusses a study on the age and body size of two populations of the frog Rana kukunoris, which is endemic to the eastern Tibetan plateau. The study compared these two qualities in breeding frogs from two localities at different altitudes with the aim of providing basic demographic information and understanding the relationship of age and body size with local climate conditions. Skeletochronology was used to determine the age of the frog specimens. It was found that the minimum age at maturity for male frogs was three years and four years for females. A positive correlation between age and body size for males and females at both study sites was observed.