With extra testosterone, frogs intimidate their rivals a lot more
Some frogs intimidate their male rivals with an evolving leg movement. In a laboratory experiment, they found that with more testosterone, the intimidating effect increases.
The rock frog from Borneo can’t scream very loudly. However, it knows very well how to threaten other frogs. His tactic is to lift one leg and, fully extended, drag it across the floor.
To humans, this display may sound funny, but it has a significant and significant effect on the amphibian environment.
worm stimulus
If a frog sees an object that moves in parallel, such as a worm moving along the ground, it is looking at its dinner. On the other hand, if you see a similar shape that moves perpendicularly, very different from a worm, you think it’s a threat that you have to run away from because it causes fear. Scientists call this latest move an anti-worm stimulus.
Frogs have developed this visual system to hunt worms and stay safe from larger predators. Now, researchers suggest that some male frogs evolved to take advantage of their ancestors’ fears. They do the paw movement to scare off the competition.
Researchers believe they could amplify wing-beating behavior in Borneo toads with a dose of testosterone, according to a recent article published in the Proceedings of the Royal Society B.
The study indicates that the hormone acts on the muscles of its legs to exaggerate the gesture, meaning that the more testosterone the frog has, the greater its display. This demonstration, heightened by the sex hormone, suggests that frogs have evolved a way to exploit their competitors’ visual perceptions to appear more dangerous.
Visual impact for males of your species
The rock frogs of Borneo are one of many frog species that move their legs to communicate. In the wild, male Borneo frogs congregate beside fast-flowing waterfalls and streams, which are very noisy. So they developed the visual cue for this move.
They have white webs between their toes, which makes their paws even more visible among the dark rocks. It seems to have an impact only among male frogs because when a female approaches the stream, she shows little preference and mates with the first male she sees.
The author of the study, Matthew Fuxjager, had previously investigated how a dose of testosterone in frogs increased the frequency of leg movements. but he is Nigel Anderson, a graduate student in his lab and also the author of this article, wanted to take a closer look.
Fuxjager and Anderson analyzed the results of frogs at the Vienna Zoo, some injected with testosterone and others with a saline placebo.
Days passed without making a gesture. Until a little frog moved one of his legs. The researchers tracked each frog’s big toe. Those who received doses of testosterone stretched their legs 10 millimeters longer than the other frogs. The more vertical the opening of the foot, the more threatening the gesture for the competitors.
Scientists have indicated that the sex hormone’s influence on this gesture means that the frogs developed it because it has a strong visual impact on its male competitor.
The eccentricities of rock frogs and the difficulty of recording them make it difficult to study them further. Those who are dosed only feel comfortable surrounded by a group of other frogs. Furthermore, they are all tiny and very difficult to distinguish from each other.
REFERENCE