Sexual selection in amphibians

Sexual selection in amphibians involves sexual selection processes in amphibians, including frogs, salamanders and newts.

Many frog species have regular breeding seasons. During these times, males gather by the water and make different kinds of calls to attract females. The strongest males usually have the deepest calls and the best spots, and females often choose their mates based on these calls.

In salamanders and newts, males compete for the attention of females. They perform special courtship behaviors to keep a female’s interest. In some species, males can store sperm for a long time during the breeding season. This competition and choice lead to differences between males and females in size and behavior, known as sexual dimorphism.

Selection in salamanders

In salamanders, males do special things to get the attention of females. They might stand still, follow females, leave scent trails, or move their tails in special ways. Males can also release special chemicals called pheromones to interest females and have a better chance of reproductive success.

For example, in the red-legged salamander, males put these chemicals on the female’s nose. In the smooth newt, males wave their tails to send the chemicals to the female.

Females pick mates based on things like body size, which can show health and good genes. Bigger males often have more success in having offspring. Females also have ways to decide which sperm will fertilize their eggs, storing sperm in special glands until they are ready.

Vocal signaling in frogs

Male frogs use special calls to attract females and show they are ready to mate. These calls help females find the right species and choose a mate. Some females like long calls, while others prefer short, quick calls.

When a female shows interest, male frogs change their calls to become more attractive. They might call more often or use different sounds. Some frogs even change their body movements to catch a female’s attention. Making these calls uses a lot of energy, so the strongest males can call the longest and loudest. They have special vocal sacs and strong muscles to help them make these calls.

Polygynandry in frogs

In many frog species, both females and males breed with more than one partner. This means a female frog may mate with several males at different times. This helps make sure her eggs are fertilized, even if some males are not the best parents. It also helps protect her babies from dangers like bad weather or animals that might eat them.

In some frogs, males help look after the young by carrying tadpoles to safe water. By choosing more than one male, females increase the chances that some of her babies will survive. Some males try to mate by pushing other males away or leaving early. This can also lead to females mating with multiple partners. This helps females make sure their eggs develop properly.

Dimorphism and morphology

Sexual dimorphism means that male and female amphibians can look different. In many salamanders and frogs, females are bigger because they need to carry more eggs. This helps them have more babies.

Size can also help males win contests. Bigger males often win because they can protect their spots better. Some frogs, like the tusked frog and fanged frog, have special things to defend against rivals. But not all frogs are big; some smaller males use smart tricks to find mates.

Sexual role reversal in Dendrobates auratus

In the green poison-dart frog Dendrobates auratus, scientists saw an interesting pattern in how males and females act during mating. In many animals, males usually try to find females, but in this frog, things seemed a bit different. Researchers looked at two ideas: one that the roles were switched, and another that females wanted the best fathers.

They found that while females sometimes competed, males also tried to find mates. But, females were very careful in choosing their partners. They likely wanted males who would take good care of their young. Females even tried to keep their chosen males from mating with others. This behavior shows that females were looking for the best care for their young, rather than a true switch in roles.