Washington, Apr 16 : Being an aggressive macho male doesn't mean that you will always get the girl, for according to a new study, the fainthearted do also have a good chance of winning the heart of the fair damsel.

Researchers have for long been puzzled by the knowledge that if aggression makes men more likely to father kids, then all males should be selected to be very aggressive. However, this is not the case.

In a study on fruit flies, the boffins carrying out the study noted that the females of the species sometimes choose males who do not fight, and sometimes choose males for no obvious reason.

This, they say, may help explain the large variation in aggressiveness in most species, including humans.

One reason for this variation, they added, could be that no fighting strategy works all the time.

"We showed in fruit flies that even the most genetically aggressive flies can have an Achilles heel, and lose against males who are (for the most part) wimps," study leader Brad Foley, from the University of Southern California.

"There's no single way to win a fight, or win mates. Females didn't necessarily prefer aggressive males -- some males mated less when they lost fights, but some males mated more if they didn't fight. Moreover, different females preferred different males.

"Unexpected interactions between individuals can define winners and losers (so-called 'chemistry'). In order to understand why flies, and humans, and other animals, are so genetically different from each other, we need to stop imagining there's a 'best' kind of strategy," he added.

The research team also included Larry Cabral of Cal State Sacramento (co-corresponding author with Foley), and Foley's supervisor Sergey Nuzhdin, professor of molecular and computational biology at USC.

The study appears in PLoS ONE.

ANI