Washington (AFP)
For the first time, scientists have described the harem of a frog from the Brazilian rainforests, showing that polygyny, or the exclusive reproduction of a male with several females, is a behavior also practiced by amphibians.
This mode of reproduction is the most common in the animal world, whether in fish, reptiles, mammals, birds and certain invertebrates, explains zoologist Fabio de Sa, from the Universidade Estadual de Campinas to AFP. .
But until the publication of this study in the journal Science Advances on Wednesday, it had never been described in an amphibian.
The lucky one is Thoropa taophora, a brown or red frog. The team of scientists filmed several in relatively poor freshwater areas, the species' breeding site, to see if the scarcity of the resource was influencing amphibian polygyny.
The images confirmed the existence of exclusive relationships between a male and, always, two females. One of the two females was still dominant.
Dominant females approached males and positioned themselves under them, for reproduction. The secondary female passively witnessed the scene.
Sometimes a female would devour the eggs protected by the male, who often hunted down the troublemaker, but sometimes reproduced with her, leading to the laying of new eggs carrying the genes of that female. The researchers analyzed the DNA of the tadpoles to confirm this.
The presence of tadpoles from the same parents but much older confirmed that the relations between frogs were long.
The advantage of polygyny, for the male, is to ensure his descendants while diversifying the genetic reservoir.
As for the female, the advantage is "that it is better to have a quality male and a quality reproduction site, even if it means sharing it with another female, rather than being exposed, not finding another frog or find a lower quality frog ", says Fabio de Sa.
Another rare phenomenon observed: competition between females, the dominant one responding to the croaking of the male and seeming to expel the other female.
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