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Testes asymmetry theory predicts that males in good condition or mature age may be able to develop larger degrees of directional asymmetry than males in poor condition or young age. We tested the testes mass and testes asymmetry hypothesis in the Chinese endemic frog (Rana omeimontis). The results showed that R. omeimontis had a significantly directional testes asymmetry, with left testis being significantly larger than right testis. Male body condition was negatively correlated with relative testes mass, but not correlated with testes asymmetry. However, male age was correlated with testes mass and asymmetry, suggesting males with larger testes and a higher degree of testis asymmetry survive better. [ABSTRACT FROM AUTHOR]

Sexual dimorphism is commonly regarded as an outcome of inter-sexual differences in intensity of sexual selection. In this view, the inter-sexual difference in mass of hind limb muscles of Bufo andrewsi in relation to sexual selection was investigated by dissecting four hind limb muscles (sartorius, plantaris longus, triceps femoris and gastrocnemius) from the left and right side of each individual. The results showed that females significantly exceeded males for muscle sartorius, muscle plantaris longus and muscle gastrocnemius and total mass, independent of body size. There are no significant differences in the four hind limb muscles mass between amplectant and non-amplectant males. Relative hind limb muscle of females is significantly larger than males, but it is not different between amplectant and non-amplectant males. There was no significant or positive correlation between relative hind limb muscle mass and SVL for any of the toads. [ABSTRACT FROM AUTHOR]