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Phenotypic flexibility of morphological characters is widespread in the animal kingdom. In the present paper, we investigated altitudinal variation in organ size (heart, lungs, livers, kidneys and digestive tract) in the spotlegged treefrog (Polypedates megacephalus) across three populations along an altitudinal gradient in southwestern China. Both heart and lung mass increased with altitude, and is possibly linked to a lower oxygen supply at high elevations; a higher liver mass suggested the increased need for energy stores. Despite significant differences between populations, we found no distinct cline in the length of the digestive tract according to altitude. [ABSTRACT FROM AUTHOR]

Variation in temperature and breeding season length caused by altitude has long been considered a major influence on the evolution of life-history traits in amphibians. Here, we examined differences in reproductive investment (testes mass and sperm length) of male spot-legged treefrog (Polypedates megacephalus) from two altitudes (680 m and 1300 m above sea level) in Guizhou Province, western China. Relative testes size from the high-altitude population was larger than that of the low-altitude population, whereas sperm length exhibited a converse cline. Testes mass but not sperm length increased with body size at both altitudes. Our findings suggest that differences in reproductive traits between populations might result from differences in the level of sperm competition. [ABSTRACT FROM AUTHOR]

The brain is the most important organ associated with demands on cognitive ability, and selection pressures have been implicated to explain variation in brain size and brain architecture in a wide range of taxa. Using phylogenetic comparative methods, we studied the effect of spawning location (terrestrial, lentic and lotic) on variation in the size of different brain parts among 43 Chinese anuran species. Spawning location was not significantly associated with relative brain size, and there were no links between spawning location and independent contrasts in size of the olfactory bulbs, telencephalon, optic tecta and cerebellum. However, the independent contrasts in size of the olfactory nerves differed significantly among the three types of spawning location. Our findings provide evidence that the brain structures underlying olfaction are linked to lifehistory attributes required for spawning in specific habitat types. [ABSTRACT FROM AUTHOR]

Brain size variation across the animal kingdom can be interpreted as a trade-off between selective advantages of higher cognitive ability and the prohibitively high energy demands of a large brain. The Expensive-Tissue Hypothesis (ETH) predicts that brains are costly, and increases in brain size will decrease the size of other metabolically costly tissues. Here, we tested this prediction using the anuran Rana omeimontis. Brain size was negatively correlated with gut length, supporting the ETH. We did not find associations between brain size and the size of other organs (heart, liver, lungs, kidneys), but found positive correlations between brain mass and testes as well as limb muscle mass when correcting for the effects of body condition. The negative correlation between gut length and brain mass suggests that diet quality may play a role in the evolution of brain size in R. omeimontis. [ABSTRACT FROM AUTHOR]

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]

Global mean temperatures have increased by 0.3-0.6°C since the late 19th century, affecting the physiology, distributions, phenology and adaptations of plants and animals. In the Qinghai-Tibet Plateau, average annual temperatures increased by an average of 0.25°C per decade from the 1970s to the 1990s, and by an average of 0.34°C per decade thereafter. Using museum collections from the 1950s to the 2000s and published references, we tested the hypothesis that body size of the toad-headed lizard Phrynocephalus vlangalii in the Qinghai-Tibet Plateau declined between 1954 and 2008 as a response to global warming. However, body size of males and females did not vary significantly between 1954 and 2008, probably due to the reciprocity between higher food availability and earlier age at sexual maturity. We suggest that human activity might result in declining population sizes in the future despite the lack of an apparent current response to changing climates. [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.

The article presents a study using the predictions of the sperm competition theory to see if these can be applied to the polyandrous Omei treefrog (Rhacophorus omeimontis). The theory predicts that subordinate males may experience a higher intensity of sperm competition than dominant males resulting, in larger testes, larger sperm and greater longevity. Findings showed that small males do not invest more in sperm than large males and that they do not have larger sperms or greater longevity.

The article focuses on testis asymmetry in dark-spotted frog Rana nigromaculata. Testis asymmetry is common in some animals and it was explained that this happens because one testis grows more to compensate for the reduced function of the other testis. The authors conducted the study with the goal of testing whether frogs possessed significant differences in left and right testes size. The male R. nigromaculata were collected in northeastern Sichuan, western China and the testes comparison was done using a paired t-test. They found that the R. nigromaculata's left testes were significantly larger and added that it was much larger in larger and older male dark-spotted frogs.