Female frogs respond better to the romantic calls of urban male frogs compared to rural male frogs, researchers have found.
In a new study, the researchers observed the mating competition between túngara frogs to understand how species' mating signals and sexual display are affected by their changing environment. They found that male túngara frogs increased the conspicuousness of their mating calls as a response to city life.
The findings were published in the journal Nature.
Urbanized Male Túngara Frogs
Several studies have been conducted to probe how animals are reacting and adapting to urban life. However, there are more to learn about how amphibians and reptiles are modifying their behaviors in response to city life.
For male túngara frogs, at least, the change in their environment has been mostly positive for their sex lives. Researchers discovered that female túngara frogs find male túngara frogs from the city more attractive than their forest counterparts. That is because urban male túngara frogs call more and have more complex vocalization.
The researchers used a generic computer-generated frog calls that were broadcast in the city and in forests. They found that it is harder for male túngara frogs to find a mate in the city and therefore, they have to work a little harder to attract a female.
However, when 20 forest and 20 urban female túngara frogs were added to the experiment, the researchers found that both groups tended to hop toward the more elaborate calls of male urban frogs.
The study explains that predators and parasites are a lot rarer in urban areas than in forests, allowing frogs to turn up the conspicuousness of their calls without fear of attracting the wrong attention. The researchers also suggest that city frogs might have a different larynx and hormone levels that allowed them to make their calls more complex than forest frogs.
Will The Changes Be Permanent?
The researchers hope to learn more about the changes, including whether the trait that is apparent in urbanized túngara frogs will be passed down to their descendants with a large-scale breeding project.
"Just as we change our social relationships in cities, animals are changing their relationships and their behavior in the radically altered biological communities we are creating across the globe," stated Rachel Page, co-author of the study.