PREDATOR: Overtly sexual women may be seen to pose an evolutionary threat, prompting "mate-guarding" behaviours in other women.

A recent study suggests women who dress provocatively are likely to be criticised by their peers amid fears they pose a threat to those in otherwise monogamous relationships.

Researchers from McMaster University in Canada invited 86 undergraduate students to take part in a discussion on conflict in female friendships.

While waiting for the study to begin an attractive woman entered the room dressed either conservatively in corduroy pants and a loose T-shirt that hid her hips, legs and chest, or in a mini-skirt and tight-fitting clothing that showcased her curves and breasts.

The subjects were then recorded with hidden cameras to gauge their reactions.

Using what the researchers referred to as a "bitchy" scale, 13 independent women were asked to view the recordings and take note of how participants reacted towards her - including verbal and non-verbal - without being made aware of how she was dressed in each of the tapes.

In the second part of the study, 66 female participants were given colour photographs of the control subject in which she appeared conservative, provocative or overweight and provocative.

The viewers were then asked to rate on a scale from one to 10 how likely they would be introduce her to their boyfriends, and if they would want their boyfriends spending time alone with the her.

The results were depressingly predictable.

"Participants displayed a strong negative reaction to the attractive female when she was dressed provocatively," said study author Dr Aanchal Sharma.

"This almost never happened when she was dressed conservatively.

In addition, participants were also less likely to introduce the attractive female to their boyfriends or allow them to spend time with her when she appeared sexy, compared to when she wore conservative clothing."

Whether viewing photos of someone who was slim or carrying a bit of extra weight, the responses were the same across the board, with the participants dismissing any woman who dressed in a "sexy" manner.

With comments such as "Her boobs are hanging out" and "She's a slut" and suggestions that she was dressed to have sex with a professor, Sharma admits that, while the results were on track with what she and co-author Dr Tracy Vaillancourt had expected, the blatant vitriol was still startling.

"The results were pretty much what I thought they would be," she said.

"I was surprised with the overwhelmingly, almost unanimous, results in the provocative condition.

When reviewing the hidden videotape recordings I was also surprised that some participants made comments about the attractive female confederate while she was still present in the room."

In addition to the comments, participants also gave non-verbal cues to indicate their displeasure: from "once-overs" - an evaluative up and down shift of the eyes - to purposeful staring and negative facial expressions such as wincing.

Sharma describes these types of responses as "mate-guarding", which are "behaviours intended to prevent competitors' access to and preserve one's access to their mate."

"A woman who 'gives the milk away for free' may reduce the mating value of another woman who seeks a long-term, committed relationship," she stated.

"There's an unspoken rule between women that takes the form of standards, conventions and expectations.

"If a female dresses in a way that suggests she's open to having sex, or attracts sexual attention to herself, she's violating the standards of the group.

"Females put these violators in place by aggressing against them.

"This takes the form of gossiping, damaging her reputation and excluding her from the group."

Though the research denotes a certain evolutionary underpinning, it's not all bad.

Rather than paint a picture that seeks to enforce negative gender stereotypes, the study's overall aim is to provide a platform from which to better understand and address the issues of bullying among women.

"I am certainly not saying that women are doomed. I think this provides a starting point for reform," said Sharma.

"There has been a lot of pressure for education policy reform to respond to bullying as a growing issue.

This research provides support for the innate roots of female conflict.

While we may not be able to prevent negative thoughts and emotions that drive a lot of conflict among females, this research is certainly a starting point for recognising the origins of the behaviours and informing what factors should be considered in the resolution process."