Kelly Osbourne and Lady Gaga take note: bitchy feuding between women is a sign of being insecure about mating.

A study suggests that harmful gossip between females is rooted in competition for a mate. It seems the high-stakes evolutionary battle has turned on its head the old saying "sticks and stones may break my bones, but words will never hurt me."

Many would argue that, among women, few things do more harm than underhand gossip designed to undermine other females.

In this theatre of war, bitchiness is dubbed 'indirect aggression' and it is females who wage it most. Whereas more than half of 15-year-old girls use "indirect aggression," only 20% of boys do so.

Writing in Philosophical Transactions of the Royal Society B, Dr Vaillancourt of the University of Ottowa said: "The fact indirect aggression is primarily used by teenage girls and young women, who direct their aggression at same sex peers, is in keeping with the hypothesis indirect aggression is used in the context of competing for mates.

"A clear way indirect aggression serves an individual's goal is by reducing her same sex rivals' ability, or desire, to compete for mates."

According to Vaillancourt, being a bitch may also be a way for a woman to minimise the risk of damaging her offspring's survival chances. Throughout human history, it has been key for a mother to stay alive in order for her infant to survive. If aggression were used physically and not verbally, then the risk of personal injury or even death would increase.

Dr Vaillancourt said: "This is typically accomplished in a concealed way which diminishes the risk of a counter attack.

"Although indirect aggression is used effectively by girls and women in a manner that reduces the aggressor's risk, it is not used without peril."

Indirect aggression may also be used by women against other females who are seen as sexually overactive because they damage other women's chances of finding a mate, by oversupplying sex and so cutting demand for it from males. Being an attractive female puts a woman in the firing line by making them a target for rivals whose own mating prospects are damaged by being plain Janes in comparison.

Dr Vaillancourt said: "Females, not males, suppress the sexuality of other females and they do so by using informal sanctions such as ostracism and derogatory gossip.

"In other words, females punish other females who seem to make sex too readily available using indirect aggression. There are some studies supporting this line of reasoning."

In experiments, young women were paired off with females who were dressed in glamorous clothing or alternatively modestly dressed. The vast majority of the subjects displayed indirect aggression. Dr Valliancourt carried out more experiments which showed women perceived an attractive female as a rival, whom they would try to keep away from their own partner.