Sexual selection in frogs

Sexual selection in amphibians involves sexual selection processes in amphibians, including frogs, salamanders and newts. Prolonged breeders, the majority of frog species, have breeding seasons at regular intervals where male-male competition occurs with males arriving at the waters edge first in large number and producing a wide range of vocalizations, with variations in depth of calls the speed of calls and other complex behaviours to attract mates. The fittest males will have the deepest croaks and the best territories, with females known to make their mate choices at last partly based on the males depth of croaking. This has led to sexual dimorphism, with females being larger than males in 90% of species, males in 10% and males fighting for groups of females. .

There is a direct competition between males to win the attention of the females in salamanders and newts, with elaborate courtship displays to keep the females attention long enough to get her interested in choosing him to mate with. Some species store sperm through long breeding seasons, as the extra time may allow for interactions with rival sperm.

Important aspects of courtship displays include male alert posture, approach and pursuit, the marking of the substrate trail, and tail undulations. Once a male has the attention of the female, he may release pheromones, which are used for individual recognition, mate recognition, and mate choice decisions, and generally increase female receptivity towards the male’s spermatophore and improve his chances of reproductive success with her. In the red-legged salamander (Plethodon shermani), males directly apply pheromones onto the female's nares. In the aquatic smooth newt (Lissotriton vulgaris), the pheromones are delivered indirectly; the male wafts them towards the female with his tail. In some species, it has been shown that the size a larger, more elaborate male’s tail has played a role in the female’s decision to mate. In the newt species of the Italian crested newt (Triturus carnifex), males that possessed large mid-dorsal body crests were more favorable to the females looking to mate.

...
Wikipedia