To gain access to females, male European frogs harass and intimidate females and force them to mate. These efforts can cause reproductive failure in both individuals and cost the female her life.Previously thought to be passive and unable to resist male coercion, recent research shows that Royal Society Open Science Journal This indicates that females have different strategies to avoid males they do not want to mate with.
Sexual conflict can arise when men and women have different reproductive interests and strategies. During her short two-week breeding season in spring, the sex ratio is often heavily biased towards males. As a result, many individuals gather together and compete with each other for females. “In the end, women lose.” [in this scenario]because they often die. [they are] “It was drowned by a swarm of up to eight frogs sitting on top of it,” explains Iñigo Martínez Solano from the Biodiversity Department at Spain’s National Museum of Natural Sciences. Such pile-ons are known as mating balls.
Carolyn Dietrich, a scientist at the Konrad Lorenz Institute of Ethology in Vienna, Austria, collected 96 female and 48 male common frogs during the breeding season. She placed the male in a box containing 5 centimeters of water with two females of different sizes and allowed them to roam freely for an hour while videotaping their behavior. Although the males did not pick up on the rejection cues, the researchers found that the females used avoidance behavior to keep the males away.
Among these frogs’ mate avoidance strategies, the most common was rotation, in which females attempt to rotate around their own axis to escape the male’s grasp. The second is protest. Dietrich describes this behavior as a “deep, low-frequency” growl, which he believes is an imitation of the release calls males make when fighting with each other. They may also emit high-frequency sounds described as “chirps.”
The last and “most surprising” behavior was tonic immobility, or playing dead. The female will extend her arms and legs firmly away from her body and appear dead for several minutes. In one of the videos analyzed, a male was observed dragging a motionless female. After her release, the female holds her position until the male turns her around, after which she swims away. This is very unusual behavior.
Tonic immobility is typically associated with strategies to avoid predation, but it has only been observed in spiders and dragonflies “as a last resort” in mating situations, the researchers note. Often used in combination, the operation worked. Of the 54 females grabbed by the male, 25 were able to shake him off and escape. Smaller females have a higher success rate because they are easier to escape from the male’s grasp. Although the study was conducted in the lab, Dietrich believes female frogs would exhibit similar behavior in the wild.
Rejection by women is a matter of preference. Often they do not mate with the first male that captures them, choosing instead to mate with the male with the deepest call, or with the male with the loudest call. After being rejected, some males catch females by surprise to try their luck again, but this clinginess does not guarantee fertilization. If the woman does not accept his advances, she will activate an escape strategy. “We have observed cases where females carry males on their backs for days or weeks, waiting for a larger male or another male of their choice,” Martinez-Solano observes. Unlike females, males appear to be less selective. They capture mates at random and show no preference regarding female body size. Their aggressive behavior is a result of this species’ short heat cycle.
Dietrich believes that these strategies were not discovered because previous studies tended to focus on male reproductive behavior. “but [research] We are gradually changing to include women’s perspectives,” she says. Martinez emphasizes that research like Dietrich’s is positive because it contributes to our understanding of amphibian biology, where “there is a huge lack of knowledge.” Understanding them better will help discover their demographic aspects and apply that knowledge to effective protection measures.
Dietrich explains that the behavior she detected in no way threatens the reproduction or survival of the species. But climate change happens. Although a common species, European frog populations are in decline. The ones that survive are the best adapted or those that can adapt to changing environments. To summarize, Dietrich quotes her doctoral supervisor, Mark Oliver Radel, who says, “There’s nothing a frog can’t do.”
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