Females tend to select the more attractive of two potential mates but in a new study, researchers have found that the female túngara frogs that live in Central America are susceptible to the so-called decoy effect.
The decoy effect is a popular marketing trick wherein a customer's preference between two options is changed when presented with a third unappealing option.
An example of this is when a customer prefers buying a cheap and compact car over a spacious but more costly sedan. When the salesman offers a decoy option, a third car about as large as the sedan but costs far more, the customer tends to change his mind and goes for the sedan.
For their study, which was published in the journal Science on Aug. 28, Amanda Lea, from the University of Texas at Austin, and Mike Ryan, from the Smithsonian Tropical Research Institute in Panama,found that the female túngara frogs were susceptible to switching their preference over two mating calls once they hear a third and unattractive mating call.
The male frogs of this species make calls to woo female frogs, which tend to like lower-frequency and longer calls and faster call rates. Such calls indicate that the male producing the croak is more energetic.
For the study, the researchers presented 80 female túngara frogs with three recorded mating calls, which vary in attractiveness and speed of repetition.
The researchers initially presented the frogs with two options and the amphibians often prefer the one with the most quickly repeated call but when the researchers presented a third option, which was as attractive as the call they have rejected earlier but much slower, the frogs' preference changed.
They did not pick the third option but instead of picking the most quickly repeated call as they had at first, opted for the call that they initially rejected.
"We tested female frogs with three simulated males who differed in relative call attractiveness and call rate. In binary choice tests, females' preferences favored stimulus caller B over caller A; however, with the addition of an inferior "decoy" C, females reversed their preferences and chose A over B," the researchers reported in their study.
Kimberly Hunter, from Salisbury University in Maryland, said that giving the female frog a third option may have made decision-making harder, which is the same with humans.
"If you're a female and you go to a bar, there are a lot of males there. We have a hard time. So do the frogs," Hunter said.
Photo: Brian Gratwicke | Flickr