Sperm traits in relation to male amplexus position in the Omei treefrog Rhacophorus omeimontis, a species with group spawning

Sperm competition theory predicts that subordinate males may experience a higher intensity of sperm competition than dominant males if mating tactics are constant, resulting in larger testes, larger sperm and greater longevity. We tested if these predictions can be applied to the polyandrous Omei treefrog (Rhacophorus omeimontis). Our results showed that relative testes size did not differ between amplexed males and satellite males, indicating that satellite males might not show signs of higher intensity of sperm competition compared to amplexed counterparts. Sperm size and longevity did not differ significantly between amplexed males and satellite males. Sperm size and longevity were not significantly correlated with each other, and sperm size does not correlate with sperm competition intensity. Our findings suggest that mating position is not related to measures of sperm competition intensity in the Omei treefrog.