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Charles Darwin had placed females in the centre of the mate debate. He had suggested that males "adapt and compete" for the attention of females because the females have the power to choose their mates. Yet, a new study by researchers at McMaster University counters this claim and says that probing fruit flies shows that females have no particular sexual preferences. This, therefore, conflicts with 150 years of "evolutionary theory" linked with the mating choice.

"Darwin's female-choice theory has become the foundation for explaining the presence of exaggerated secondary sexual traits in many males, such as the peacock's tail feathers," said Rama Singh, one of the study's authors, in a press release.

"It has also led to a cottage industry based on the idea that female choice is based on the genetic quality of the males, known as the 'good gene hypothesis,'" added Singh. "Sexually exaggerated traits are said to be male advertisements to females of their good genes when in fact they may simply be a means of making the male more visible to females or intimidating other males."

Another idea is the influence of the Victorian period during Darwin's time. Perhaps he thought that females had more power in sexual negotiations than they really have. For instance, a female opting for a bigger male rather than a small one might be due to force or threat, or perhaps because the bigger male has removed his rivals.

To test their idea, the team used a garden fruit fly, Drosophila, and enabled a female to get sexually aroused with either a large or a small male. When the females were later offered two new males---one large and the other small, they showed that the females did not opt for the bigger ones. Once they were aroused they did not show any preference for a particular mate.

Singh does not believe in "pure male charm". Male actions can be seen to be influenced by force or physical threat. They can also be part of "male sex drive," which is rather supportive of Darwin's "female choice" theory.

Among humans, Singh feels that "sexual behaviors are not hardwired or completely uncontrollable". We all take actions assuming that we can control or moderate our actions through social interactions and the idea of the brain controlling our body.

The study was published in the Dec.11,2015 issue of PLOS One.